Phẫu Thuật Bỏng: Tiếp Cận Và Phương Pháp Điều Trị Từ Trung Quốc (Chinese Burn Surgery)

13/10/2026 • by Bs CKI Phẫu thuật tạo hình, tái tạo và thẩm mỹ Trương Hoài Anh •

Tổng hợp những kinh nghiệm lâm sàng và phương pháp điều trị bỏng tiên tiến từ nền y học Trung Quốc. Cuốn sách bao quát từ hồi sức cấp cứu bỏng, xử lý hoại tử, ghép da vi mảnh đến phẫu thuật phục hồi chức năng và thẩm mỹ sẹo di chứng bỏng.

📂 Chuyên mục: Tài liệu thẩm mỹ, Phẫu thuật tái tạo, Điều trị sẹo

🏷️ Từ khóa: phẫu thuật bỏng, điều trị bỏng, tái tạo sẹo bỏng, burn surgery, ghép da

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189
g
h
m
n
o
i
k
l
j
Fig. 8.7 (continued)
8.3 Reconstruction of Patients with Multiple Deformities After Extensive Severe Deep Burns and Lacking of Donor Skin

190
closed directly. It would take longer time to heal than
the normal skin. When expanders were used, because
the incision was on the scarred skin, it took longer time
to heal, and the blood supply and elasticity of the
scarred skin were not as good as the normal skin. The
ﬁ rst injection into the expander was about 10–12 days
PO and 1–2 times per week. To prevent the suture site
from being broken, the injection volume should be
proper and less. Generally, it takes 2 months or longer
to get the satisfying expanding outcome. Establishment
of scar skin blood supply with this method was slower
than that of normal skin graft. The tie-over dressings
should be untied 12 days PO.
Achilles tendon scar ﬂ aps were used to reconstruct post-
burn talipes equinus, talipes equinovarus, etc.
In summary, the patients who survived the extensive
severe deep burn always sustained multiple deformities after
the wound healed and lacked of donor skin. Expanded
medium split-thickness scar skin or thin split-thickness scar
skin could be used to reconstruct the deformities after con-
tracture released, and satisfying results were achieved. If the
bone, joints, and tendon were exposed, however, expanded
scar ﬂ aps could also be used for reconstruction. It was shown
that the methods mentioned above were new, safe, and effec-
tive for reconstruction of this kind of postburn deformities
with extremely limited donor skin.
a
b
c
Fig. 8.8 Patient Meng: burns of 96 % of TBSA, third-degree burn of 68 % (1960). ( a ) Transported by helicopter to our hospital. ( b ) Extensive
severe deep burn. ( c ) Group photo with his families

8 Reconstruction of Burn in the Late Phase

191
Fig. 8.9 Patient Guan, female: burns of 90 % of TBSA, third-degree
burn of 70 %, and severe burn on both hands. ( a – d ) Both hands were
severely burned. ( e , f ) Ten ﬁ ngers were charred burned fourth-degree
burns. ( g , h ) Amputation of ten ﬁ ngers. ( i , j ) Satisfying function of the
hands and joints
a
b
c
d
e
f

8.3 Reconstruction of Patients with Multiple Deformities After Extensive Severe Deep Burns and Lacking of Donor Skin

192
8.4
Repair of Claw Hand Deformity
After Burn
Xiaoyuan Huang
Hands actively participate in daily activities of a human;
therefore, hands are the most vulnerable parts of the
human body, and most burns of the hand are limited to
the dorsal surface as the hand is clenched during injury.
The functional repercussions of severe burns on the hands
are obvious, especially typical claw hand resulting from
incorrect treatment of deep burns of the hands. Without
reconstruction, these contractures can lead to permanent
skeletal deformities and functional deficits, and delayed
release prolongs the impairment of patient function.
Patients with severe claw hand deformity after burn
should be operated within 3 months. Deep partial- thick-
ness or full-thickness burns have significant morbidity in
terms of time for healing, infective complications, and
subsequent scarring. Conservative management leading
to spontaneous healing usually involves prolonged and
painful dressing changes, and the resultant scar is invari-
ably hypertrophic, leading to cosmetic and functional
debility. Thus an early surgical approach that tries to
preserve the dermis and achieve wound healing is
preferred.
8.4.1
Pathogenesis and Clinical Presentation
As burn wounds on the dorsum of the hand begin to close,
they may cause MCP joint hyperextension and IP joint ﬂ ex-
ion, leading to what is known as a claw hand deformity. The
hand becomes ﬂ at in its palmar surface and the deﬁ nition of
the palmar arches is lost. These contractures were mainly
due to shortage of skin and soft tissue; joint deformities
developed secondary to that.
Because of the anatomical structure on the dorsum of
the digits, burns through to the extensor tendons can
result in boutonnière deformities even with complete
g
h
i
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Fig. 8.9 (continued)
8 Reconstruction of Burn in the Late Phase

193
wound closure. Extension contractures at the metacar-
pophalangeal joint are also common because the burn
and subsequent scarring are limited to the dorsal
surface.
Not infrequently the burn surgeon encounters the so-
called claw hand, in which the thumb is ﬁ xed in adduction
resulting from contracture of adductor pollicis and the ﬁ rst
dorsal interossei muscle, the metacarpophalangeal joints are
in hyperextension, the ﬁ ngers at the proximal interphalan-
geal (PIP) joints are in ﬂ exion as a result of disruption of the
central slip, and the distal IP (DIP) joint hyperextends due to
sliding of tendons medial and lateral around the proximal
interphalangeal joint.
8.4.2
Prevention
Prevention of claw hand deformity requires a correct ini-
tial diagnosis and treatment that makes possible cover-
age of the burned hands as soon as possible. Superficial
partial- thickness burns on the hand often heal without
the need for skin grafting. During dressing therapy, the
wrist should be placed in mild extension, the metacarpo-
phalangeal joints in 90° of flexion, the interphalangeal
joints in extension, and the thumb in abduction. Patients
should be encouraged to begin range-of-motion exer-
cises as soon following burn injury as possible. Range-
of-motion exercises reduce extremity edema, and the
return of function should be optimized once the skin
wounds have healed.
If it is clear that a burn wound will not heal within
3 weeks, the best treatment is excision and grafting. Early
excision and grafting has also decreased the frequency and
severity of contractures and hypertrophic scarring; occa-
sionally, however, one still encounters patients who were
treated “expectantly” with late grafting and disastrous
results. Releases can be performed by either incising scars
or excising scars; it will usually improve the appearance and
quality of the tissue that is retained. With few exceptions,
burns of the hand should be grafted with sheet grafts. Graft
take should be assessed at postoperative day ﬁ ve, and the
decision for initiation of range-of-motion exercises should
be made. Once graft healing is complete, compression
gloves, which will minimize hand edema and possibly scar
hypertrophy, should be worn. With deep burns on the hands,
it is important to begin treatment as soon as possible with
press therapy, especially if the healing process has been
delayed or when there is a personal or family history of
hypertrophic scarring. They should be used for at least
6 months after the burn, and often for longer, until we
observe ﬂ attening of the scars, which will progressively lose
their bright red color and will become softer and more
pliable.
8.4.3
Classiﬁ cation
Classiﬁ cation of claw hand deformity in relation to skeletal
deformities and functional deﬁ cits is useful in describing
injuries and prognosis. Three classiﬁ cations are the most
commonly quoted classiﬁ cation for claw hand deformity:
minor degree claw hand deformity indicates that extension
contractures at the metacarpophalangeal joint are less than
30° with the impairment of ﬂ exional function (Fig. 8.10 );
moderate degree claw hand deformity indicates 30–90°
extension contractures at the metacarpophalangeal joint with
the loss of ﬂ exional function due to joint stiffness and tendon
adhesion (Fig. 8.11 ); and severe degree claw hand deformity
is characterized by severe scar contracture on the dorsum
with loss of function and the patients loss of ability to take
care of themselves (Fig. 8.12 ).
8.4.4
Timing and Principle of Repair
The choice of the appropriate intervention and the timing of
reconstructive surgery are the essential ingredients that result
Fig. 8.11 Moderate grade claw hand deformity
Fig. 8.10 Minor degree claw hand deformity

8.4 Repair of Claw Hand Deformity After Burn

194
in either successful or unsuccessful claw hand deformity
reconstruction. Deformities corrected at an earlier date showed
better functional recovery than those which were treated at a
much later date. According to the traditional view, surgical
release of contractures should preferably await scar matura-
tion. Release of an active vascular scar is thought to increase
the likelihood of suboptimal results and early recurrence, pos-
sibly because of vigorous local tissue responses precipitated
by the trauma of the release procedure. Unfortunately, delayed
release prolongs the impairment of patient function. Patients
with severe claw hand deformity after burn should be operated
within 3 months, especially for pediatric patients.
Deep partial- or full-thickness burns if untreated,
neglected, or managed conservatively can develop dysfunc-
tional scar contractures with severe deformities and signiﬁ -
cant reduction in patient’s activities of daily life. These burn
sequelae can require multistage procedures to restore anat-
omy and function. The repair operation of claw hand defor-
mity consists in correction of adduction of the thumb and the
region of ﬂ exion contractures of the metacarpophalangeal
articulations, syndactyly, and ﬂ exion contractures of the ﬁ n-
gers; these procedures need an overall planning and individ-
ual choice.
Generally speaking, the metacarpophalangeal joint needs
to be replaced after scar release at ﬁ rst, and then ﬁ nger ﬂ ex-
ion deformity is corrected by scar release and skin graft. But
for some severe ﬁ nger ﬂ exion deformity, these ﬂ exural ﬁ n-
gers will handicap the reposition of metacarpophalangeal
joint and have to be extended by scar release and skin graft
ﬁ rstly, then scars in the dorsum of the hand were loosened,
and metacarpophalangeal joint were repaired. If the metacar-
pophalangeal joint will have to be narrowly replaced, the
hand will have to be a ﬁ st and the palm skin unavoidably
becomes eroded.
8.4.5
Surgical Technique
8.4.5.1 Scar Excision and Release
The scarred skin on the dorsum of the hand was excised
keeping down the superﬁ cial vein to the wound as integrally
as possible; when necessary thin scar was preserved in order
to not to expose the tendon. For minor or moderate degree
claw hand deformity, the ﬁ rst web and other four ﬁ nger webs
will be corrected at the same operation after release of dor-
sum, but for some severe claw hand deformity, the scarred
web need to be cut ﬁ rstly and then sutured to form artiﬁ cial
syndactyly in order to easily close by ﬂ ap after unattached
satisfying replacement of the metacarpophalangeal joint.
8.4.5.2 Reposition of Metacarpophalangeal Joint
It is very important to overcome the hyperextension of the
metacarpophalangeal joints after scar release in the dorsum
of hand. At ﬁ rst, it is likely to reduct the metacarpophalan-
geal joints by continuous passive motion and extraction. But
sometimes aggressive contracture release of the joints,
tendons, and soft tissue is required for optimal results in the
correction of severe postburn hand deformities, including
capsulotomy, collateral ligament excision, extensor tenot-
omy, and excision arthroplasty.
For most instances, position can be maintained easily
with splints. But for some severe claw hand deformity, con-
sideration should be given to ﬁ xing the digits in extension at
the proximal interphalangeal joint and ﬂ exion at the metacar-
pophalangeal joint by insertion of threaded Kirschner wires
after the tendons were released, the stiff metacarpophalan-
geal joints were mobilized by closed capsulotomies, and the
contracture of the thumb web space was released.
8.4.5.3 Reconstructive Options
In most cases, grafting is frequently the preferred choice
when large full-thickness or deep partial-thickness defects
are involved (Fig. 8.13 ). Split-thickness grafts are more often
used, because full-thickness grafts entail the creation of a
deep donor site wound, which can itself be susceptible to
contracture and scarring and precludes the use of the site for
subsequent regrafting procedures. The hand was placed in
ﬁ st position when placing the graft so that the amount of
graft material needed can be better estimated.
Reconstruction involved application of the dermal regen-
eration template and subsequent placement of an epidermal
autograft, and some resulting defects need to be closed with
distant ﬂ aps transferred with either traditional or microsurgi-
cal techniques, when protection is required for an exposed
vital structure, such as the nerve or joint. The abdomen is a
favorite donor site of large, distant, axial ﬂ aps for hand resur-
facing (Fig. 8.14 ).
Fig. 8.12 Severe degree claw hand deformity

8 Reconstruction of Burn in the Late Phase

195
a
b
c
Fig. 8.14 ( a ) Initial appearance. ( b ) Tubed inferior epigastric ﬂ ap. ( c ) Final result
a
b
Fig. 8.13 ( a ) Initial appearance.
( b ) Final result

8.4 Repair of Claw Hand Deformity After Burn

196
8.4.6
Rehabilitation
General rehabilitation was performed routinely after opera-
tion, primarily physical therapy, pressure garments, and
splinting. Continuous passive motion alternating with active
ranging and nocturnal splinting may be necessary.
Physiotherapists and occupational therapists were involved
at the preoperative stages. It is also important to emphasize
to parents to let the child use his or her hands as soon follow-
ing injury as possible.
8.4.7
Basic Tenets
The basic principles for prevention and treatment of claw
hand deformity can be summarized as follows:
1. For deep partial-thickness or full-thickness burns, an
early surgical intervention that tries to preserve dermis
and achieve wound healing is preferred.
2. Deformities corrected at an earlier date showed better
functional recovery than those which were treated at a
much later date. Patients with severe claw hand deformity
after burn should be operated within 3 months.
3. The repair operation of claw hand deformity needs an
overall planning and individual choice.
4. It is important to perform general rehabilitation after
repair operation.
8.5
Surgical Treatment of Scar and Ulcer
on the Heel
Xiaoyuan Huang
Calcaneus is the attachment point of many tendons, espe-
cially of the Achilles tendon. Serious injury on the heel with-
out timely repair will affect lower limb function. The skin
and dermis in the plantar region are much thicker, and the
subcutaneous tissues are more compact. The plantar fat pad
is rich in ﬁ brous connective tissue and the plantar fascia is
much tougher, and there are also anchor ligaments which
connect the subcutaneous layer and the plantar fascia. The
ligament divides the subcutaneous into many ﬁ brous septa
which make the skin unmovable and can bear pressure, fric-
tion, twisting force, and the weight of the body. The heel is
the most important weight-bearing point. The repair of soft
tissue defect on the heel is always a matter of great impor-
tance for its special anatomical physiological characteristics.
In the 1960s, almost all of us used cross-leg ﬂ aps or tubular
skin ﬂ aps to repair the soft tissue defect on the heel, but more
surgical methods were investigated and the outcome
improved continuously for the application of microsurgical
technique.
8.5.1
Repair Method
Many methods can be used to repair the soft tissue defect
on the heel, and they are mainly based on the severity of
the defect. We can select full-thickness skin grafting
because it can reach the aim of reserving function if the
plantar fat pad is intact; otherwise we can only use ﬂ aps
for the repair.
8.5.1.1 Pedicled Skin Flap
The pedicled skin ﬂ ap utilizes the nearby axial vessel as the
main blood supply vessel. When the ﬂ ap is pedicled with the
axial vessel, it can be designed as island ﬂ ap, peninsular ﬂ ap,
or fascial pedicled ﬂ ap in anterograde or retrograde type and
be transferred under different angles to repair the heel. In the
past, the reverse island ﬂ ap was designed according to the
intermuscular branch of the posterior tibial artery, anterior
tibial artery, or retrograde peroneal artery, but these methods
damage the leg greatly because one of the principal vessels
was used. Now, the clinical application of these reverse
island ﬂ aps decreased gradually, and we are most in favor of
the application of fascial ﬂ ap, perforator ﬂ ap, and neurocuta-
neous vascular ﬂ ap. Perforator ﬂ aps whose supply vessels
are still big enough for anastomosis after traversing through
the deep fascia may be supplied by septocutaneous perfora-
tors or musculocutaneous perforators. The use of perforator
ﬂ aps is a common trend in ﬂ ap transplantation because they
have the advantages of not damaging the main vessel, not
cutting the main muscle, and not affecting the motor func-
tioning. Medial supramalleolar skin ﬂ ap, lateral supramalle-
olar ﬂ ap, and retrograde sural neurocutaneous vascular ﬂ ap
are the most frequently used ﬂ aps for repairing defect on the
heel.
8.5.1.2 Medial Malleolus Retrograde Flap
1. The posterior tibial artery patency and the site of the
upper cutaneous branch of the medial malleolus are
examined using the Doppler ﬂ owmeter.
2. The axis line lies at the connecting line between the point
of middle-upper 1/3 of the medial margin of the tibia and
middle point of the medial malleolus and Achilles ten-
don; the pivot point is at the point 3–5 cm above the
medial malleolus.
3. The delimitation of donor site: The medial border is the
medial margin of the tibia, the lateral border is the poste-
rior midline of the leg, and the superior border can reach
the inferior border of the knee joint. The length and width
of ﬂ ap should be 1–2 cm larger than that of the recipient
site.
4. The skin and subcutaneous tissue of the medial and lat-
eral border are incised until the sublayer of the deep fas-
cia at the proximal end of the ﬂ ap; then the ﬂ ap is
separated till the point of about 3–5 cm above the medial
8 Reconstruction of Burn in the Late Phase

197
malleolus and the fascial perforating branch of the poste-
rior tibial artery is identiﬁ ed; and then the cutaneous part
of the pedicle is incised, the fascial perforating branch is
carefully separated preserving a width of 3–5 cm of the
fascial pedicle, and the ﬂ ap is ﬁ nally harvested. The ped-
icle of the ﬂ ap can be designed in island or peninsular
shape (Fig. 8.15 ).
The blood supply of the medial malleolus retrograde ﬂ ap
is supplied mainly by the septocutaneous perforators which
branch at the lower one third of the posterior tibial artery.
There are about 1–3 perforators at both sides with average
outside diameter of 0.7 mm. These perforators form longitu-
dinal anastomosis. The veins of the ﬂ ap consist of superﬁ -
cial and deep groups: The deep group has always only one
and is thicker than the artery; it courses with the artery and
inﬂ ows into the posterior tibial vein at last; the superﬁ cial
group is the great saphenous vein and its tributaries. There
are many communicans between the two groups which are
the anatomical foundation of the medial malleolus retro-
grade ﬂ ap. The venous drainage system of the fascial pedi-
cled medial malleolus retrograde ﬂ ap is the two mentioned
groups. Medial malleolus retrograde ﬂ ap is supplied by the
posterior tibial artery, posterior tibial vein, and small cuta-
neous veins.
8.5.1.3 Medial Plantar Skin Flap
To make clear the unobstructed rate of the anterior and pos-
terior tibial vessels and the blood supply of the foot by
Doppler or even angiography detection, then the ﬂ ap is
designed according to the shape and area of the wound on the
foot. The axial vessel of this ﬂ ap comes from the terminal
branch of the posterior tibial artery. Posterior tibial artery
travels between the medial malleolus and calcaneus, passes
through abductor hallucis, and branches into the medial
plantar artery and lateral plantar artery. The skin is inner-
vated by the medial plantar nerve which is the terminal
branch of the tibial nerve. The medial plantar artery and
medial plantar nerve always go together. The ﬂ ap is designed
on the top of the foot arch, not on the weight-bearing area,
and in round shape about 8 cm × 4 cm.
The skin is incised along the vessel axes in the posterior
aspect of the medial malleolus, the posterior tibial vessel and
tibial nerve are exposed and separated, dissection is done
along the vessel until the margin of the designed ﬂ ap, then
incision of the medial margin of the ﬂ ap is done, and the
abductor hallucis is divided and separated until the point
where the posterior tibial artery branches into the medial
plantar artery and lateral plantar artery. The medial plantar
artery is dissected without cutting off the lateral plantar
artery, and then 2–3 skin perforators can be found. After
knowing where the skin perforator is, the lateral margin of
the ﬂ ap is incised, the ﬂ ap is separated on the shallow surface
of plantar fascia till the point of the skin perforator, and then
the ﬂ ap is raised from the deep surface of the plantar fascia
and even with some muscle if necessary. Attention should be
paid to protecting the medial plantar nerve during the opera-
tion; the ﬂ ap may have sensory function if the control nerve
bundles can be separated and preserved (Fig. 8.16 ).
a
b
c
Fig. 8.15 Medial malleolus retrograde ﬂ ap for repairing defect of skin and soft tissue with bone exposed in ankle area. ( a ) Preoperation. ( b – c )
Postoperation

8.5 Surgical Treatment of Scar and Ulcer on the Heel

198
8.5.1.4 Sural Neurocutaneous Vascular Flap
Flap Design
The ﬂ ap is designed according to the wound on the heel. The
axis line lies at the connecting line between the middle point
of poplitea area and the middle point of the connecting line
between malleolous lateralis and tendo calcaneus, that is, the
surface projection of the small saphenous vein and sural
nerve; the rotating point is 3–5 cm above the lateral malleo-
lus; and the width of the skin and fascia on the pedicle is
3 cm. Only fascial pedicle can also be designed.
Incisional Method
1. Axial pattern fascial ﬂ ap:
The skin is incised till the subdermal surface in an
S-shaped incision on the pedicle; both sides are separated
without damaging the fascia, the small saphenous vein in
the fascial pedicle is wrapped, and then the subcutaneous
tissue and deep fascia of the pedicle in the Achilles tendon
side is incised and is included in the ﬂ ap. The ﬂ ap is lifted
forward and the fossa of lateral malleolus is dissected
carefully. 2–3 skin perforators of the peroneal artery are
located in the region of the malleolus ﬁ bulae pointing
about 3–5 cm above the malleolus, and then the skin, sub-
cutaneous tissue, and deep fascia in the tip and bilateral of
ﬂ ap are incised. Also to make sure that the sural nerve is
included in the ﬂ ap at the same time. The upper septocuta-
neous perforators and proximal end of the small saphe-
nous vein are ligated, the ﬂ ap and its pedicle are separated
below the deep fascia retrogradely, and the ﬂ ap is trans-
ferred to the recipient site through a tunnel or not.
2. Axial pattern fascio-cutaneous ﬂ ap:
The method is almost the same as that of the abovemen-
tioned; the difference is that the latter consists of the same
skin width as that in the pedicle (3–4 cm). The posterior mar-
gin of the pedicle is incised at ﬁ rst to the deep fascia, then an
extended incision to the wound on the heel and the ﬂ ap is
drawn forward, and the septocutaneous perforators of pero-
neal artery are identiﬁ ed near the rotating point where the
perforator is located. The margin of the designed ﬂ ap is
incised, the subcutaneous adipose tissue is separated on both
sides of the incision, and the deep fascia is incised so we can
ensure the deep fascia is wide enough. The ﬂ ap below the
deep fascia is raised till the perforator and is transferred to
the recipient site in the surface channel method.
The donor vessel of the ﬂ ap is the sural neurovascular
bundle which is supplied by the perforating branch of the
peroneal artery. The sural neurovascular bundle feeds the
skin nearby; at the same time it supplies blood to the sural
a
b
c
Fig. 8.16 Medial plantar skin ﬂ ap for repairing of soft tissue defect on heel. ( a ) Preoperation. ( b ) Introperation. ( c ) Postoperation

8 Reconstruction of Burn in the Late Phase

199
nerve and connects with the vascular network of the deep
fascia through the connection of the septocutaneous perfora-
tors of the peroneal artery and musculocutaneous perforators
of the posterior tibial artery. There are many anastomotic
branches, so the blood can ﬂ ow in both directions, which
ensure the blood supply of the ﬂ ap.
The ﬂ ap must be separated below the deep fascia, not only
because the loose connective tissue is easy for separation but
to not injure the vascular network of the deep fascia, or else
it will damage the blood supply of the ﬂ ap. The deep fascia
should be harvested wide enough, especially near the pedi-
cle, in order to ensure the blood supply of the ﬂ ap. Some of
the peri-tendon loose tissue should also be preserved when
separating the ﬂ ap which is better for the survival of the skin
graft.
8.5.1.5 Free Flaps
It is needed to anastomose small vessels in a free ﬂ ap
transplantation,so the doctor should possess microsurgical
technique and there should be suitable vessel in the recipient
site. Because the anterior and posterior tibial vessels often
are damaged in burn wound, traumatic wound, and espe-
cially high-voltage electric burn wound, we should pay
attention to the blood supply of the foot preoperatively, or
else this will cause foot ischemia postoperatively.
Scapular Skin Flap
The blood supply of the scapular area comes from the scap-
ular artery. The subscapular artery branches from the axil-
lary artery, then descends along the anterolateral margin of
the subscapular muscle, and branches into the thoracodor-
sal artery and circumﬂ ex scapular artery. The circumﬂ ex
scapular artery passes through the trilateral foramen (the
upper, lower, and lateral borders of the trilateral foramen
are the teres minor muscle, teres major muscle, and long
head of the triceps muscle, respectively) and divides into
the subscapular and descending branches at the lateral side
of the axillary margin of the scapular slightly. The descend-
ing branch goes along the external margin of scapula and
toward the dorsal side. It divides into the posterior and par-
ascapular cutaneous branches. The distribution area of the
circumﬂ ex scapular artery is from the spine of the scapula
to the costal margin and from the spinous process to the
posterior axillary line. The circumﬂ ex scapular artery and
its cutaneous branches often have two accompanying veins.
The caliber of circumﬂ ex scapular artery is about 2–3 mm
at the initiating terminal; the vein is about 3–4 mm. We can
cut the vascular pedicle at different levels according to our
need so as to control vascular pedicle length. This cut is of
three types:
Type A: The vascular pedicle is cut at the level of the
descending branch, the vascular pedicle length is 4–6 mm,
and the artery caliber is 1.5–2 mm.
Type B: The vascular pedicle is cut at the level of the circum-
ﬂ ex scapular artery, the vascular pedicle length is
7–10 mm, and the artery caliber is 2.5–3 mm.
Type C: The vascular pedicle is cut at the level of the sub-
scapular artery, the vascular pedicle length is 11–14 mm,
and the artery caliber is 3–4 mm.
The scapular ﬂ ap can be designed as horizontal, vertical,
and inverted-L shapes according to the blood supply. The
tuberosity of the lateral margin of scapula is felt to determine
the surface location of the trilateral foramen. It is about 7 cm
below the middle point of the spine of the scapula. The pedi-
cle of the circumﬂ ex scapula is dissected at ﬁ rst and the inci-
sion is done above the trilateral foramen, going along the
posterior margin of the deltoid muscle from the posterior axil-
lary fold to the middle point of the spine of the scapula. The
skin and subcutaneous tissue are incised, teres minor muscle
is exposed, and circumﬂ ex scapular artery in the loose con-
nective tissue is identiﬁ ed. Sometimes, obvious vessel pulsa-
tion can be observed after drawing the teres minor muscle
aside. The vascular pedicle is dissected slightly, then the dis-
tal side of the designed ﬂ ap is incised, and the ﬂ ap under the
deep fascia toward the pedicle is raised. Near the trilateral
foramen, the ﬂ ap is separated from the lateral margin of the
scapula or even some muscle is included so as not to damage
the vascular cutaneous branch.
Typical Case
A ﬁ fteen-month-old male was scalded at the plantar surface
some time after his birth. The wound was healed after local
dressing changes but with scar proliferation and contracture
which caused ﬂ exion deformities of the toes. At ﬁ rst, we
excised the scar on the right foot and repaired the wound
with the left scapular skin ﬂ ap. Three months later we excised
the scar on the left foot and repaired the wound with the right
scapular skin ﬂ ap. The donor sites were repaired by direct
suture. Satisfactory results were obtained (Fig. 8.17 ).
Anterolateral Femoral Skin Flap
1. Flap design:
The midpoint between the exterior margin of the ante-
rior superior iliac spine and the exterior margin of the
patella is the location of the ﬁ rst myocutaneous artery
perforator. The line between this point and the midpoint
of the inguinal ligament has the surface projection of the
descending branch of the lateral circumﬂ ex femoral
artery. The location of the second and third myocutaneous
artery perforators is at the inferolateral side of the ﬁ rst
myocutaneous artery perforator. The ﬂ ap is designed
including the ﬁ rst myocutaneous artery perforator accord-
ing to the size of the wound.
2. Expose the blood vessel and nerve:
The medial margin of the ﬂ ap is incised and the inci-
sion is extended to pulsating site of the femoral artery.
8.5 Surgical Treatment of Scar and Ulcer on the Heel

200
The skin, subcutaneous tissue, and fascia lata are incised,
and the fascia lata is dissected until the junction of the
rectus femoris muscle and vastus lateralis muscle, where
the descending branch of the lateral circumﬂ ex femoral
artery lies below the rectus femoris muscle. The rectus
femoris muscle is drawn to the medial side, thus expos-
ing the descending branch of the lateral circumﬂ ex femo-
ral artery and the neurovascular bundle. Dissection is
carried on until the site where the musculocutaneous per-
forators of the medial and lateral branches enter the mus-
cle (intermuscular space of the medial vastus muscle and
lateralis vastus muscle). Then the lateral margin of the
ﬂ ap is incised, and dissection is done inwardly between
the fascia lata layer and muscle membrane, where many
small cutaneous branches of the musculocutaneous
artery can be found. The musculocutaneous artery is
a
b
c
d
e
f
Fig. 8.17 Bilateral free scapular ﬂ aps for repairing of bilateral plantar scar contracture. ( a ) Preoperation. ( b–e ) Introperation. ( c ) Postoperation

8 Reconstruction of Burn in the Late Phase

201
separated from both sides, some muscle can be included
for protecting the vessel, and the upper and lower mar-
gins of the ﬂ ap are cut at last. The lateral femoral circum-
ﬂ ex vessel is reanastomosed with the posterior tibial
vessels (Fig. 8.18 ).
8.5.2
Method Selection
This section illustrates several methods. How to select a
method is based on where and how serious the defect is and
whether or not the method can meet the demand of recon-
struction and restoring the function. The principles for
repairing planta pedis are as follows:
1. The subcutaneous tissue should be thick enough and with
good elasticity.
2. The transferred tissue should be with sufﬁ cient blood
supply and friction tolerant.
3. The sensory function can be recovered favorably. Based
on the above principle, if the plantar fat pad is intact, we
can select full-thickness skin graft which can tolerate cer-
tain pressure and friction in the near future and can
recover almost all normal functions 1 year later. If the
plantar fat pad is seriously damaged, without soft tissue
pad or with bone exposure, we can only select ﬂ ap graft.
In order to select a suitable ﬂ ap, we should not only fol-
low the above principles but also consider the patient’s
requirement. The ﬁ rst choice for those soft tissue defects
on the heel is medial plantar island skin ﬂ ap; it has the
advantages of similar tissue structure to that of the heel,
good wear resistance, and having sensory function. The
medial plantar island skin ﬂ ap is the best donor site for
repairing the defect on the heel but not around the heel
because the plantar fascia is always damaged and should
be repaired by skin grafting which will affect the elastic-
ity of the foot arch.
There are many application reports of retrograde ﬂ ap of the
leg. Such as the medial supramalleolar skin ﬂ ap which is sup-
plied by the skin perforator of the posterior tibial artery, the
lateral supramalleolar skin ﬂ ap which is supplied by the perfo-
rator of the peroneal artery, and the sural neurovascular ﬂ ap.
These ﬂ aps can be operated simply without vascular reanasto-
mosis. People’s requirement of beauty becomes higher and
higher along with the development of the society. And now,
we must consider the aesthetic shape of the leg when we want
to choose it as a donor site. The author’s opinion is not to
choose the leg as the donor site for repairing the wound on the
heel, especially for young patients, so as not to affect the leg’s
shape, but to choose distant free ﬂ aps. Along with the popular-
ization and improvement of microsurgical technique, the suc-
cess ratio of using free ﬂ ap to repair wound on the heel is very
high and even higher than that of the pedicle ﬂ ap. And these
ﬂ aps, with abundant blood supply and chilblain resistance, are
better than the retrograde ﬂ ap of the leg.
The ﬁ rst choice of free ﬂ ap for repairing wound on the
heel is the scapular ﬂ ap and anterolateral thigh ﬂ ap. They
have the following advantages:
1. The supplying vessels are invariable and superﬁ cial and
so are easy to be exposed, the vascular pedicle is long
enough, and the vessel caliber is large enough and often
more than 2 mm.
2. The donor site is large enough. The color, the texture, and
the thickness of the ﬂ ap are appropriate. The ﬂ ap can repair
the defect of the whole plantar involving the adjacent area
and can be designed according to the shape of the wound.
3. The donor site is concealed and easy to be accepted.
4. The ﬂ ap can be transferred by microvascular anastomosis
or in the form of island ﬂ aps to repair local defect.
5. The lateral femoral cutaneous nerve in the anterolateral
thigh ﬂ ap can be anastomosed with the sensory nerve of
the recipient area, and the vessel of the ﬂ ap can be used as
a bridge grafting vessel.
a
b
Fig. 8.18 Free anterolateral femoarl skin ﬂ ap for repairing of soft tissue defect on heel. ( a ) Preoperation. ( b ) Postoperation

8.5 Surgical Treatment of Scar and Ulcer on the Heel

202
For children, the defect on the heel should be repaired in an
early period so as not affect the growth of the foot. The typical
case, a 15-month-old child with scar proliferation on both
plantar and ﬂ exion deformities of the toes, repaired by two
scapular skin ﬂ aps, is the youngest patient who accepted the
operation of transferring two free scapular skin ﬂ aps. The old
textbook emphasized that the child who accepts the operation
of free ﬂ ap should be 3 years old because the vessels of the
children are much thinner, the dissection and reanastomosis of
the vessels are more difﬁ cult, the operating time is much lon-
ger, and the anesthetic tolerance is poor. But now, the micro-
surgical technique is more advanced and the operation can be
carried out in two groups at the same time, one group for dis-
secting the ﬂ ap and the other for scar excision, so the operating
time is almost the same as that of the operation of skin graft.
For children who are below 3 years old, we can consider free
ﬂ ap transplantation based on our technical conditions.
8.5.3
Key Points on Preoperative and
Postoperative Treatment
Generally, the injury is not only limited to the heel but also
involves the damage of the tissue and vessel of the adjacent
area. Many injuries involve a damage of the anterior or pos-
terior tibial vessels. When we repair the heel, we must exam-
ine the blood supply of the foot preoperatively and pay
attention to the condition of vascular patency during the
operation, especially to avoid ischemic necrosis of the foot.
The length of the axial vessel should meet the need of the
recipient site. We often use the proximal end of the damaged
vessel for anastomosis and should also cut out the vessel
with stenosis caused by inﬂ ammation until the normal vessel
is seen. For some serious injury which cannot be repaired by
local skin ﬂ ap or without suitable vessel for anastomosis, we
should change our operative plan and use bridging free ﬂ aps
or the old cross-leg ﬂ aps.
The Marjolin ulcers are often infected, and they are the
common ulcers on the heel. When we deal with these ulcers,
we must repeatedly wash the wound with hydrogen peroxide
solution, physiological saline solution, and disinfectant after
excising the lesion tissues and place negative pressure drain
device under the ﬂ ap to avoid infection because of the poor
ability of the foot to ﬁ ght against infection.
For the Marjolin ulcer, we must completely excise the
local lesion and perform groin lymphadenectomy. If we are
not sure whether the malignant tissues were excised com-
pletely, we cannot use ﬂ ap for repairing because the ﬂ ap will
conceal the tumor recurrence. The pathological nature of
Marjolin ulcer is usually squamous cell carcinoma and well
differentiated. The lesion is often limited to the local site and
develops slowly, so the prognosis is usually good. If the
wound cannot be repaired, we can only choose amputation.
We should protect the ﬂ ap after operation no matter
what kind of ﬂ ap it is. The sensation of the ﬂ ap recovers
very slowly even though the sensory nerve was anasto-
mosed, except for the sensation of the medial plantar ﬂ ap
with sensory nerve, so we should avoid them in scald
injury, cold injury, stick injury, or long-time compression
and protect them with sponge mat. The patients can
recover and walk gradually with sensory recovery half a
year later.
8.6
Reconstruction of Perineal Region
Cicatricial Contracture
Xiaoyuan Huang
Perineal region burning does not happen frequently due to its
position. But once it happens, the incidence rate of wound
contamination and local infection is very high due to the
physiological speciﬁ city; wound healing will be delayed;
hyperplasia and proliferation, such as limited limb abduction
and knee joint arthrogryposis; will ﬁ nally occur (Fig. 8.19 );
Fig. 8.19 Extensive scar formation in the perineum and thigh region

8 Reconstruction of Burn in the Late Phase

203
and in some cases, abdominal scar and accretion of the peri-
neal region will cause ﬂ exion deformity of the hip joint
(Fig. 8.20 ).
Webbed scar will appear when perineal region cicatri-
cial contracture is limited on the mons pubis and medial
surface of the thigh and buttocks (Fig. 8.21 ). Buttocks
malformation will happen when extensive scars formed,
and cicatricial contracture will lead to faked anus malfor-
mation (Fig. 8.22 ) and even results in faked atresia and
penis dislocation. Even worse, serious scar will limit
patient from crouching, standing, and sitting. Children’s
sexual organ development will be inﬂ uenced, and even
organ malformation can happen. The patient will suffer a
lot, so the reconstructive operations should be carried out
early, especially for the children to avoid malformations of
genitalia development.
a
b
Fig. 8.20 Scar contracture in lower abdomen, perineum and thigh
Fig. 8.21 Webbed scar in perineum

8.6 Reconstruction of Perineal Region Cicatricial Contracture

204
8.6.1
Restorative Procedure
The patient is placed in lithotomy position, and bilateral
hip joints should be abducted thoroughly so as to expose
the area involved in scar, which should be released thor-
oughly. Different methods should be carried out according
to different patient. Z-plasty or ﬁ ve-ﬂ ap plasty is suitable
for webbed scar reconstruction. For other cases split-thick-
ness skin graft can satisfy the goal, while ﬂ ap or skin
expander can achieve the restoration too. The principles
are as follows: ①Scar should be released thoroughly to cor-
rect sexual organ and anus malformation and restore
abduction of the hip joint. Solving difﬁ cult defecation and
urination is superior. Anterior perineum cicatricial con-
tracture should be ﬁ rstly removed. The raw surface cannot
be repaired with skin graft and should be reconstructed
with ﬂ aps.
8.6.2
Scar Release and Skin Grafting
Scar on the perineal region should be released extensively to
reset the genitalia; a webbed scar should be used so as to
decrease skin grafting. The whole piece of skin is efﬁ cient
to reduce scar formation and restore satisfying appearance
(Fig. 8.23 ). The skin donor site of the patient who suffered
from large area burning is not easy to get, and joining
together of smaller pieces can be an alternative (Fig. 8.24 ).
Cicatrix skin graft and scalp can be used for some cases.
Sometimes the skin can be harvested ﬁ rstly, and then the
patient’s position can be changed to release the scar. Split-
thickness skin grafting is the most popular choice, because
epidermal free skin will be likely to contract.
8.6.3
Flap Reconstruction
After relaxing the scar of the perineal region, soft tissue
becomes frequently abundant; split skin grafting is capable
of covering the raw area, but in cases of scars due to electric-
ity injury, deep soft tissue is often lost and accompanied with
defects of the greater lip of pudendum, scrotum, and testis. In
these cases only ﬂ ap grafting can be chosen for reconstruc-
tion. The ﬁ rst choice is approximate ﬂ aps, such as abdominal
ﬂ ap, lateral anterior ﬂ ap, tensor fasciae latae ﬂ ap, and medial
femoral ﬂ ap. If the condition does not permit, free ﬂ ap graft-
ing should be carried out. The condition of the donor site and
recipient site should be weighed. If direct closure cannot be
accomplished, skin grafting must be chosen; then the appear-
ance of the donor site will be far from ideal. If the donor site
can be closed primarily and can be hidden easily, the cos-
metic outcome is satisfying, skin grafting is not necessary,
and hyper scar development is avoided. For certain, the most
popular choice is groin ﬂ ap because it has many merits.
8.6.4
Groin Skin Flap
8.6.4.1 Blood Supply
The blood supply origin of the groin ﬂ ap is multiple, with the
cutaneous branches of the superﬁ cial circumﬂ ex iliac artery,
superﬁ cial epigastric artery, superior and inferior epigastric
artery, the 10th and 11th posterior intercostal artery, and sub-
costal artery included. Extensive coincidence among these
branches is beneﬁ cial for ﬂ ap raising. From 2.5 cm below the
inguinal ligament arises the superﬁ cial iliac circumﬂ ex
artery, superﬁ cial epigastric artery; the two vessels have a
40 % chance of belonging to the same trunk. After originat-
ing 1.5 cm from the inital point, the superﬁ cial iliac circum-
ﬂ ex artery is divided into deep and superﬁ cial branches in the
lever below thigh deep fascia, the superﬁ cial branch passes
through deep fascia and inguinal lymph nodes to supply the
skin around inguinal groove. The deep branch goes on its
way under the inguinal groove and sends out cutaneous
branches near the anterior superior iliac spine. Sometimes, it
is below the lateral femoral cutaneous nerve before it emerges
from the deep fascia. Enough care should be taken intraop-
eratively. From 2 to 3 cm above the inguinal ligament, the
superﬁ cial epigastric artery arises, goes on its way above the
middle point of the inguinal groove, then passes through the
deep layer of the superﬁ cial fascia, makes its way on through
the superﬁ cial fascia, and sends out many branches.
8.6.4.2 Flap Design
The vessel variation of the area is frequent. Doppler survey
meter can be used before operation to locate the superﬁ cial
Fig. 8.22 False anal deformation caused by scar contracture

8 Reconstruction of Burn in the Late Phase

205
circumﬂ ex iliae vessel and its course. The ﬂ ap is pedicled
with superﬁ cial circumﬂ ex iliae vessel, the point is 2 cm
below the middle point of the inguinal ligament, and the axis
is from the point of the femoral pulse to the anterior superior
iliac spine. Commonly, ﬂ ap width is 10 cm, and length can
be more than 20 cm.
8.6.4.3 Surgical Technique
Make the incision along the line; dissect the ﬂ ap on the level
just below the deep fascia, on the surface of the musculus
obliquus externus abdominis and gluteus to the inguinal liga-
ment; and raise the ﬂ ap to a shadowless lamp for a transillu-
mination test. Vessels arranged can be found clearly at those
thin ﬂ ap. For avoiding injury, seperate vessel pedicle is not
necessary but some soft tissue to the pedicle so as to harvest
an island ﬂ ap to repair the perineum (Fig. 8.25 ). Sometimes
the skin pedicle is essential to be raised. The donor site can
a
b
c
Fig. 8.23 Whole piece of skin grafting for scar contracture in perineum
Fig. 8.24 Several pieces of smaller skin graft were Joined together for
scar contracture in perineum

8.6 Reconstruction of Perineal Region Cicatricial Contracture

206
be closed primarily. The wound is just located on the edge of
the iliac crest.
Infection frequently occurs in the operation of the perineal
region, and the key treatment is appropriate preoperative
preparation and postoperative treatment. The scar on the
perineal region is usually rough and uneven in surface, dirt
easily piles up, and sinus tract will form. Three days before
the operation, the patient should have liquid diet and wash
the dirt on the perineal region, especially in the case of faked
sinus. Cleaning enema should be carried out in the evening
before the operation and the morning of the operation to
keep intestinal tract cleanness. Antibiotics should be used
routinely half an hour before the operation, at least hold on
3 days after the operation. The hip joint must be established
in abduction position with plaster bandage postoperatively.
Meanwhile keep urinary catheter in. One week postopera-
tively, the patient can take liquid diet so as to ensure no sedes
will contaminate the operative site before depacketize. At
this moment the urethral catheter can be moved, and the nor-
mal diet is recommended.
Suggested Readings
1. Huang XY, Yang XH, Lei SR, et al. Repair of deeply burned hands
with split thickness auto-skin grafting with the preservation of
denatured dermis. Chin J Burns. 2001;17(1):60–1.
2. Yang XH, Huang XY, Lei SR, et al. Long term result of repair of
deeply burned hands with large sheet of split thickness autoskin
grafting with the preservation of denatured dermis. Chin J Burns.
2005;21(1):27–9.
3. Frame JD, Still J, Lakhel-LeCoadou A, et al. Use of dermal regen-
eration template in contracture release procedures: a multicenter
evaluation. Plast Reconstr Surg. 2004;113(5):1330–8.
4. Maslauskas K, Rimdeika R, Rapoliene J, et al. The comparison of
two methods of treatment evaluating complications and deﬁ ciency
of functions of hands after deep partial skin thickness hand burns.
Medicina (Kaunas). 2009;45(1):37–45.
5. Gousheh J, Arasteh E, Maﬁ P. Super-thin abdominal skin pedicle
ﬂ ap for the reconstruction of hypertrophic and contracted dorsal
hand burn scars. Burns. 2008;34(3):400–5.
6. Tambuscio A, Governa M, Caputo G, et al. Deep burn of the hands:
Early surgical treatment avoids the need for late revisions? Burns.
2007;33(6):807.
7. Woo SH, Seul JH. Optimizing the correction of severe postburn hand
deformities by using aggressive contracture releases and fasciocuta-
neous free-tissue transfers. Plast Reconstr Surg. 2001;107(1):1–8.
8. Wang LN, Gao XS. Plastic surgery. 1st ed. Beijing: The People’s
Medical Publishing House; 1989. p. 4–10.
9. Wang W. Plastic surgery. 1st ed. Hangzhou: Zhejiang Scientiﬁ c
Technical Press; 1999. p. 3–19.
10. Gao XS. Plastic and reconstructive surgery of burns. 1st ed.
Shanghai: Bai-jai Press; 1992. p. 148–50.
11. Hamdy EL. Island adipofascial ﬂ ap for resurfacing of the Achilles
tendon. Plast Reconstr Surg. 1996;98(6):103.
12. Yang ZC. Treatment of burns. 3rd ed. Beijing: The People’s Medical
Publishing House; 2006.
13. Upton J, Beiker TM, Shoen SL, et al. Fascial ﬂ ap coverage of
Achilles tendon defects. Plast Reconstr Surg. 1995;95(6):1056.
14. Cai JF, Sun BG, Wang YR, et al. Free transplantation of anterior
rectus sheath-cutaneous ﬂ ap for the repair of the Achilles tendon
and its neighboring soft tissue defects. Chin J Plast Surg Burns.
1991;3:180–1.
15. Hong ZJ, Jiang HQ, Wang J, et al. Design of z-shaped Achilles
tendon scar composite ﬂ aps to correct the tendon-scar contracture.
Chin J Rep Reconstr Surg. 2001;15(5):308–9.
16. Chen B, Wang LN, Qiu JG. An improved method of surgical cor-
rection for scar contracture of Achilles tendon following burns and
its anatomic basis. Chin J Surg. 1982;20(10):633–5.
17. Xu DC, Zhang SM, Zhong SZ. Progress in basic study and clinical
applications of distally-based sural neurocutaneous ﬂ ap. Chin J
Clin Anat. 2005;23(4):343–4.
18. Wang W. Plastic surgery. 1st ed. Hangzhou: Zhejiang Scientiﬁ c
Technical Press; 1999.
19. Wang LN, Gao XS. Plastic surgery. 1st ed. Beijing: The People’s
Medical Publishing House; 1989. p. 4–19.
20. Chen B, Jia CY, Xu MD. Repair of contracture deformities of the
patients with extremely limited donor skin at late postburn stage.
Chin J Burns. 2003;19(6):361–4.
21. Chen B, Rang CW, Gong X, et al. Experimental study of composite
skin grafts. Chin J Exp Surg. 1990;7(1):29–30.
22. Jiang DY, Chen B, Xu MD, et al. Application of re-composite skin
graft with frozen allogenic fetal dermis and autologous epidermis
on full thickness burn excision wounds. J Forth Mil Med Univ.
1997;18(5):461–3.
23. Chen B, Jiang DY, Jia CY, et al. Experimental study and clinical
application of composite skin grafting. Chin J Burns. 2004;20(6):
347–50.
a
b
Fig. 8.25 Bilateral island iliolumbar skin ﬂ ap for repairing scar contracture in perineum

8 Reconstruction of Burn in the Late Phase

207
Z. Yang, Chinese Burn Surgery, DOI 10.1007/978-94-017-8575-4_9,
© Springer Science+Business Media Dordrecht and People’s Medical Publishing House 2015
9.1
Characteristics of Burn-Wound
Healing
Shuliang Lu, Yiwen Niu, and Qiao Liang
The primary goal of burn wound treatment is to promote
healing. A comprehensive understanding of the mechanisms
underlying wound healing is essential for the selection of
proper treatment methods. Normal wound healing is a multi-
step process involving physiological and biochemical
changes and the participation of cells, cytokines, extracellu-
lar matrix (ECM) proteins, and their interactions. It is found
that the healing process is impaired under several pathophys-
iological conditions [ 1 ]. The burn wound is different from
simple excisional wounds and cutaneous deﬁ ciency; it
involves tissue loss along with the formation of necrotic tis-
sue [ 1 – 4 ]. We will focus on the characteristics of burn
wounds and the concept of tissue repair in the present chap-
ter. The mechanisms and treatments of different types of
burns will be discussed in other chapters.
9.1.1
Thermal Injury of the Skin Tissue
9.1.1.1 Early Effects of Thermal Energy on Cells
and Molecules [ 5 , 6 ]
Heat is a form of energy associated with irregular motion of
atoms and molecules. Heat is conducted by transferring from
molecules with higher energy to those with lower energy.
Convective heat transfer occurs when thermal energy is
released from one object or absorbed by another during their
brief moment of contact. Heat is convected in a gas or a ﬂ uid.
Radiative heat transfer is the process whereby molecules
release kinetic energy in the form of electromagnetic waves.
Electromagnetic energy emitted by one body travels through
a medium or through space, to ultimately be absorbed by
another body that will transfer to other bodies in the same way.
Thermal energy can be absorbed from or by living tissue
in any of these ways. Radiation is an inefﬁ cient form of thermal
energy transfer, and only extremely high temperature (e.g.,
arc light) or prolonged exposure to high temperature (e.g.,
solar radiation in the summer) results in skin injury.
Conduction is a relatively efﬁ cient form of energy transfer
that occurs when skin contacts hot solids or ﬂ uids. Patients
with burns caused by ﬂ aming clothes may be subjected to
multiple forms of thermal energy transfer. High-intensity,
infrared rays may be released via radiation from ﬂ aming
materials (such as clothes), and heat can be conducted to the
skin from direct contact with ﬂ aming clothes. In addition,
heat in air can be transferred to the skin via convection.
Two factors should be considered in the study of the
effects of thermal energy on cells: temperature and duration
of exposure, both of which determine the degree of thermal
injury. Moritz and Henriquez were the ﬁ rst to inspect the
time–temperature relationship in thermal injury to skin. At
sustained temperatures between 40 and 44 °C, various
enzymes malfunction, and the early denaturation of protein
occurs. Cellular functions are impaired, one of which is the
membrane Na + pump; the result is a high intracellular Na +
content and concomitant cell swelling. As the temperature
reaches 44 °C and higher, damage accumulation outruns the
cell’s inherent repair mechanisms, assuming the exposure
time is long enough, and leads to eventual necrosis. Cell
membrane changes incurred during exposure to heat stress of
45 °C for 1 h can result in cell death. Oxygen free radicals
also contribute to cellular injury and death. It is a class of
oxygen species exhibiting an unpaired electron. These highly
reactive molecules are capable of promoting further damage
to the cellular membrane, leading to death. Injuries caused
by free radicals can be sustained even after the removal of
the heat source and until the temperature falls to the point at
which free radicals are no longer generated. Rapid cooling
may reduce the severity of thermal injury in cells and may
determine whether a cell survives or dies.
With increasing temperature, cellular proteins incur
increasingly severe damage. Proteins lose their structural
integrity, owing to coagulation as a result of protein dena-
turation. New aberrant bonds are formed, resulting in the
Burn Wound Healing
9
Shuliang Lu

208
appearance of structurally different macromolecules. Skin
cells can undergo rapid death upon prolonged exposure to
heat stress. Changes caused by thermal injury are usually
ﬁ rst noticed in keratinocytes. Apart from skin injury caused
by direct contact with a heat source, progressive damage
to inner skin cells may occur as a result of heat conduction
through skin tissues, which attenuates with decreasing ther-
mal energy conduction and increasing tissue depth. In 1953,
Jackson classiﬁ ed burn wounds into three zones according
to histological characteristics. Burn wounds comprise three
characteristic zones from the superﬁ cial skin to the deep skin
and from the central wound to the peripheral wound: the
coagulation zone, the stasis zone, and the hyperemia zone.
The coagulation zone is the area closest to the heat source.
Tissue in this zone comprises the initial burn eschar and is
believed to have sustained irreversible injury. Just below
and around the coagulation zone is the zone of stasis and
edema, where there is only modest denaturation of macro-
molecules and numerous cells are viable, but blood ﬂ ow is
slow or even static, owing to the impairment of regional cir-
culation. Prolonged stasis may cause viable cells to die, lead-
ing to tissue necrosis. If proper protection is provided, stasis
may be ameliorated, and the cells may recover from injury.
Because damaged cells in this zone can recover or progress
to death, tissues in the stasis zone are also called intermediate
tissues. Peripheral to the stasis zone is the hyperemia zone,
which develops in response to regional injury. Cells in this
zone will not progress to death and recover completely. The
concept of the three zones is based on the three-dimensional
aspect of the burn wound and provides a framework for
understanding the progressive development of burn wounds.
9.1.1.2 Classiﬁ cation of Burn Depth
and Histology of Burn Wounds [ 7 ]
The severity of skin burns varies with temperature and dura-
tion of high-temperature exposure. Wounds of different burn
depths undergo different pathological changes, which deter-
mine the repair patterns and the outcomes. The following
classiﬁ cation is commonly used in clinical practice to iden-
tify burn depth.
First-Degree Burn
In this kind of burn, the injury involves the stratum corneum,
stratum lucidum, stratum granulosum, and occasionally the
squamous cell layer of the epidermis. Histology indicates
cell degeneration and vascular engorgement in the papillary
layer of the dermis. The involved area is initially erythema-
tous owing to vasodilation. The pain is severe at the site of
injury owing to the stimulation to nerve endings. Generally,
the basal cell layer is not involved, and cells in this layer
possess powerful regenerative capacity. These cells may
undergo proliferation after injury, and the newly generated
keratinocytes will gradually cover the wound. Eventually,
desquamation ensues, but is followed by complete scarless
healing within 7 days. No special treatment is needed for
ﬁ rst-degree burns, which have a good prognosis. This kind
of burn is not included in the estimation of the surface area
of a burn. However, extensive ﬁ rst-degree burns will have
systemic effects, and proper therapy and care are needed.
Superﬁ cial Second-Degree Burn
In this kind of burn, the injury involves the entire depth of the
epidermis and superﬁ cial portions of the dermis. Cells in the
epidermis degenerate and become necrotic. The nuclei show
pyknosis; and the cytoplasm exhibits vacuolation or swell-
ing. Collagen denaturation in the superﬁ cial dermis and
vasodilatation in the papillary layer are usually observed.
Capillary permeability is also increased. The dermis and the
epidermis are separated, and plasma-like exudate can be
found between them. Blistering is often present. A light-red
wound bed is visible upon removal of the epidermis. Local
stimulation can cause severe pain because of the survival of
nerve endings in the mid and superﬁ cial dermis. However,
deep portions of hair follicles, sweat glands, and sebaceous
glands can be found in the dermis and form the histological
basis for healing in superﬁ cial second-degree burns.
Deep Second-Degree Burn
The wounds in superﬁ cial and deep second-degree burns are
different. Most of the dermis is destroyed and what few epi-
thelial cells remain are located in the deepest recesses of the
epidermal appendages. The separation between the epider-
mis and the dermis is not clear. Few or no blisters are found
owing to the thicker adherent overlying eschar, which pre-
vents the lifting effect of edema. The wound bed is pale, and
interspersed with red spots, which represent congested capil-
laries. The embolic rete vasculosum is present at the junction
between the epidermis and the dermis 1–2 days after injury;
and represents the typical reticular thrombus network. The
wounds are relatively insensate, owing to the impairment of
nerve endings. Pressure sensation may remain, owing to the
survival of deeply situated pressure receptors.
Third-Degree Burn
The wound involves the full-thickness of the skin and occa-
sionally even the hypodermis, muscle, or bone. Full-thickness
skin is necrotic. The elasticity of the skin disappears and
eschar occurs. Emboli are found in the deep blood vessels.
An embolic, branch-like, coarse vascular network can be
seen in the wound bed. Complete destruction of the nerve
endings results in the loss of local pain sensation.
9.1.1.3 Blisters in the Burn Wound [ 8 ]
Blisters are frequently present in superﬁ cial second-degree
burns. However, the skin is thin in children and the elderly, in
whom blisters may not be observed. A relatively deep
9 Burn Wound Healing

209
second- degree burn may have a thin eschar, which may allow
for blister accumulation.
A blister is formed by leakage of ﬂ uid from heat-injured
vessels. The ﬂ uid enters and collects, usually in the area of
the damaged dermo-epidermal junction, lifting the epidermis
away from the underlying dermis. The exudate is composed
of sodium, potassium, chloride, glucose, plasma proteins,
and various amino acids at levels similar to those in plasma.
Release of plasma proteins and skin degradation products
into the blister osmotically draws yet more ﬂ uid, causing
enlargement of the blister over time.
Recent studies indicate that growth factors, such as epi-
dermal growth factor (EGF), ﬁ broblast growth factor (FGF),
and platelet-derived growth factor (PDGF), are present in the
exudate and promote wound healing. The levels of these
growth factors are several times higher in the exudate than in
plasma. Some researchers have postulated that the blister
surface has the characteristics of a biological membrane,
protecting the wound and promoting healing. Therefore, it
may be necessary to reconsider the concept that blisters in
superﬁ cial second-degree burns need to be drained and that
the blister surface should be removed. Further investigation
as to whether to preserve blister ﬂ uid and keep blisters intact
will be helpful in the treatment of burns.
9.1.1.4 Necrotic Tissues in Burn
Wounds [ 5 , 7 , 8 ]
Heat can cause coagulative necrosis of the skin, and necrotic
tissues are commonly found in burn wounds. The necrotic epi-
dermis and dermis in deep second-degree burns become
crusted. The wounds of third-degree burns involve full-
thickness skin in which eschar is usually observed. The wound
is gray at the early stage and soft, owing to the presence of
moisture. For this kind of wound, exposure therapy can evapo-
rate the water and make the wound rigid, thin, and sallow.
Nearly all of the properties of, and beneﬁ ts provided by
normal skin are lost. The eschar no longer provides a bar-
rier – mechanical, immunological, or otherwise – to infec-
tion. In fact, it provides a medium for bacterial growth. The
ability of skin to prevent loss of ﬂ uids, electrolytes, and
plasma components is likewise absent in the eschar because
of its high degree of permeability. The massive loss of pro-
teins impairs the nitrogen balance and wound healing. Loss
of complement components and immunoglobulins aggra-
vates burn-induced immunosuppression. The presence of
necrotic tissues in the wound bed play a role in the impair-
ment of hemostasis as it promotes the consumption of clot-
ting and related factors (e.g., platelets and ﬁ brinogens. The
thermoregulatory function provided by normal skin is absent
in eschar. The protein–lipid complex formed in the skin after
a burn injury is toxic to cells and tissues. Studies have found
that massive tissue necrosis activates macrophages, lympho-
cytes, and neutrophils and the release of oxygen free radicals,
lysosomal enzymes, cytokines, and prostaglandins, as well
as leukotriene. In vitro studies have also shown that inﬂ am-
matory mediators such as tumor necrosis factor (TNF)-α in
the skin wound bed and the burn exudate can signiﬁ cantly
damage cultured vascular endothelial cells. Inﬂ ammatory
mediators released from necrotic tissues not only aggravate
local inﬂ ammatory responses and inﬂ ict undue damage, but
also directly and/or indirectly damage residual viable cells
along the wound edge and in the wound bed, such as ﬁ bro-
blasts, endothelial cells, and keratinocytes, that can carry out
tissue repair. These inﬂ ammatory mediators may also hinder
the migration of these cells to the wound bed, thus jeopardiz-
ing wound repair. Once pyrogenic substances and toxins in
the necrotic tissue diffuse into the circulation, the functions
of multiple organs can be compromised.
9.1.2
Characteristics of Burn Wound
Repair [ 7 – 11 ]
The repair of burn wounds of different depths has different
features. The repair of superﬁ cial second-degree burns is
limited to the epidermis, and connective tissues and wound
remodeling are not involved. The repair process depends on
the proliferation, differentiation, and migration of keratino-
cytes. Deep second-degree burns involve both the epidermis
and dermis, and the repair of these wounds not only relies on
the proliferation, differentiation, and migration of residual
keratinocytes, but also the proliferation of vascular endothe-
lial cells and ﬁ broblasts. The formation of connective tissue
and wound remodeling is also involved. Third-degree burns
involve full-thickness skin, in which repair depends on the
proliferation of vascular endothelial cells and ﬁ broblasts,
with the resultant formation of connective tissue followed by
wound remodeling. Because no living skin appendages
remain, repair of the epidermis can be achieved, if the tissue
defect is limited, by the proliferation and differentiation of
residual keratinocytes along the wound edge and their migra-
tion into the granulation tissue. If the extent of the tissue
defect is beyond the migration capacity of residual keratino-
cytes along the wound edge, wound repair is often not
achievable naturally and usually requires skin grafting.
Severely necrotic tissues are frequently present in deep
second- degree burns and third-degree burns. In the early
stage of the inﬂ ammatory response, a variety of cytokines
and mediators are released by inﬁ ltrating inﬂ ammatory cells
to initiate and regulate the functions of vascular endothelial
cells and ﬁ broblasts in repairing burn wounds. These inﬂ am-
matory cells also secrete various enzymes, which digest and
separate necrotic tissues and clear cell debris by phagocyto-
sis. These processes contribute to wound clearing and the
formation of a healthy wound bed, thus beneﬁ ting wound
healing. The process of clearing necrotic tissue and
9.1 Characteristics of Burn-Wound Healing

210
promoting regeneration is the primary characteristic of
wound healing in burns, which differs from that in cutaneous
abrasion or excision wounds.
9.1.3
Phenomenon of Progressive Deepening
in Burn Wounds
9.1.3.1 Jackson’s Discovery and the Phenomenon
of Progressive Deepening in Burn
Wounds
As early as half a century ago, people had observed the phe-
nomenon of progressive deepening in burn wounds, and it
often occurs a few days after injury. The process of progres-
sive injury can cause a wound to progress from superﬁ cial to
deeper. This makes the diagnosis of burn depth and the
development of wound treatment programs very difﬁ cult.
Sevitt found microcirculation changes in animal burn wound
in 1949. However, He cannot link such changes in local
blood circulation to the phenomenon of progressive deepen-
ing in burn wounds. Jackson ﬁ rst described three zones of
burn injury from the center outward in 1953. The center is a
zone of coagulation, which is caused by direct heat. It is the
irreversible coagulation necrosis zone, the outer zone of con-
gestion is a local reaction after injury, and does not usually
develop into necrotic tissue. The middle zone is stasis, where
the blood vessels expand, and the local blood ﬂ ow slow. If
the ﬂ ow has stagnated to a certain level, the zone of stasis can
be developed into necrotic tissue. However, if given reason-
able protection, the region will improve blood ﬂ ow stasis,
and gradually return to normal healthy tissue. Tissue in this
zone can develop in two opposite directions: survival or
death, and the so-called “Inter-ecological” tissue. Further
histological observation found that regional blood ﬂ ow is
still visible in the zone of stasis immediately after injury.
However, within 24 h after injury, the blood ﬂ ow has stopped
and the zone demonstrates plaque partially caused by stasis
intravascular thrombosis, increased vascular permeability,
and local edema. Blood ﬂ ow stasis often occurs within 48 h
after injury, and a progressive increase even leads to the
interruption of blood supply into the coagulation necrosis
zone. In 1963, Hinshaw found that ischemia occurred in burn
wounds without any treatment within 24–48 h after the injury
and therefore caused cellular damage and ischemia-induced
cell death, and ﬁ nally led to the wound deepening, so that the
area of original necrotic tissue expanded. This prospective
study more clearly established the relations of wound stasis
and the progressive increase in local blood ﬂ ow leading to
interruption of the blood supply with wound deepening.
Many clinical observations found that wound depth changes
2–3 days after injury, the clinical manifestations of the deep-
ening and expansion of the wound, suggesting the existence
of the phenomenon of progressive wound deepening.
Masson’s staining and anti-vimentin immunohistochemi-
cal staining is an effective, intuitive research method, which
is a histological study of deep second-degree wounds pro-
gressive deepening. Application of Masson’s staining tech-
niques make abnormal collagen stained blue or bright green,
whereas degeneration and necrosis of collagen stained
brown-red. With the anti-vimentin immunohistochemical
staining method, it speciﬁ cally labeled stromal cells, endo-
thelial cells, white blood cells, Langerhans cells and other
cell membrane vimentin antigens, and their staining once
lost, reﬂ ects the degeneration of cell damage. Therefore, it
reﬂ ected well the histological evaluation of wound tissue for
the occurrence of the damage and development by dynamic
comparative brown–red stain, as well as the regional scope
of the expression of vimentin antigen. Studies have found
that the deep second degree burn wound tissue in rats after
injury within 48 h, as time goes on, being part of the red-
dyed, denatured collagen, increased gradually, while the
bright green part of the normal collagen is gradually reduced.
The change is most obvious in the 48 h after injury.
Meanwhile, the expression of vimentin antigen on cells in
the wound gradually decreases as time goes by. It indirectly
reﬂ ects the gradual increase in necrosis and degeneration of
tissue cells; this change is also most obvious within 48 h
after injury. In addition, it is found that the normal bright
green collagen is in primary position within 24 h after injury,
while the 5 days after the injury was sustained there was a
marked increase in collagen denaturation. Within 24 h after
injury, vimentin antigen expression showed positive staining
and 5 days after injury vimentin antigen showed negative
staining, suggesting increased numbers of degenerated cells
and necrosis. The experimental results further provide direct
histological evidence of the phenomenon of progressive
deepening of the burn wound.
9.1.3.2 Advances in the Phenomenon
of Progressive Deepening
in Burn Wounds [ 12 ]
Progressive deepening in the early stages of burn injury and
development is a sequential process. Many factors are
involved in the pathological process, and various factors still
exist in the complex relationships with regulation. At this
point, the damage mechanisms of the phenomenon are not
yet fully understood. Available research data suggest that
localized edema after burn, blood hypercoagulability or a
pre-thrombosis state caused by function changes in the anti-
coagulant–ﬁ brinolytic system, and strong local inﬂ ammation
due to the existence of necrotic tissue or infected wounds are
three important reasons for the phenomenon.
Edema Formation
Local edema after burns was considered one of the reasons
for progressive wound deepening. The edema formation
9 Burn Wound Healing

211
process led not only to concentrated, increased blood ﬂ ow
stasis, but tissue edema can also lead to increased tissue pres-
sure and oppression of local micro-circulation, resulting in
further blood ﬂ ow stasis and increased tissue ischemia and
hypoxia; however, if the degree of tissue edema is reduced, it
will help wound tissue perfusion, suggesting that tissue
edema might play a role in the pathogenesis of progressive
wound deepening.
Mechanism of Local Burn Wound Edema Formation
Vascular permeability increase is the main reason for the for-
mation of burn edema. One of the reasons for the increase in
vascular permeability is that the heat caused capillary and
small vein endothelial cell damage, cell swelling, destruction
of intercellular connections, and gap formation. Fluid was
lost from the expanding endothelial gaps. Release of a chem-
ical burn medium, such as histamine, bradykinin, and oxy-
gen free radicals, is also caused by increased blood vessel
(mainly capillaries, vein) permeability. Small molecular sub-
stances and macromolecule protein leakage from blood ves-
sels can increase the osmotic pressure in the tissue space. It
is well known that the capillary gap is larger than the diam-
eter of macromolecular proteins; thus, proteins can also be
leaked from the gaps in the blood vessels, but in fact the
actual amount of protein leaked from the blood vessels is
much less than that of the small molecules. It has been
learned from the analysis of post-burn edema exudate that as
proteins, the amount of micromolecule albumin leaked is
much greater than the macromolecule globulin as well as
ﬁ brinogen. This suggests that despite the large diameter of
the vascular gap, when the substances in the blood seep out,
the blood vessels retain the characteristics of selective per-
meability for the macromolecular substance, and this results
in most of them still being kept in the lumen of the blood
vessels. It is speculated from some materials that the capil-
lary basement membrane might be used as backup to retain
the blood components leaked from the barrier damage in the
lining of the blood vessels.
The degradation of hyaluronic acid and collagen ﬁ bers by
heat and their destruction products, which are hypermolar
osmotic increases in the tissue gap. In addition, the release of
oxygen free radicals can also undermine the interstitial tissue
of the hyaluronic acid and collagen; thus, the osmotic pres-
sure of the tissue was signiﬁ cantly higher, becoming one of
the important reasons for the formation of edema.
The Arturson formula indicated that the leaking ﬂ uid
pressure within the range 200–300 mmHg could lead to the
formation of edema. Elevated capillary hydrostatic pressure
was considered to be a possible additional cause. Pitt found
that capillary pressures are nearly doubled early after a burn
injury. The ﬁ rst proposed mechanism for this process was
the involvement of chemical mediators such as histamine,
known for its ability to dilate arterioles. The histamine
receptor antagonists (such as H 2 receptor blockers) can
block the occurrence of burn edema. The latest research
shows that the histamine, which is mediated by releasing
nitric oxide, plays a vasodilator function. Yet another view
was that histamine’s role in the production of burn edema
may occur through its stimulation of oxygen free radical
formation. Various prostaglandins found in burn ﬂ uid may
also be involved in the occurrence of edema. Study of the
product prostaglandin inhibitors (such as indomethacin,
nicotinic acid, ibuprofen) on the impact of edema found that
these substances can reduce edema, but the lymph protein
showed no obvious change, indicating that the size of the
capillary pores is unchanged by the drug. It suggested that
the role of prostaglandin substances to increase capillary
pressure mainly occurs through the vasodilation rather than
increased capillary permeability. Capillary ﬁ ltration pres-
sures may also be raised by impairment of the venular out-
ﬂ ow caused by erythrocyte stasis and agglutination in
post-capillary venules. This stasis could be a result of ﬂ uid
loss from a more proximal capillary, and heat-induced
erythrocytes having lost some of the ability to bend and
deform to pass through small vessels. In addition, the plate-
let and neutrophil adhesion to the capillary and venous
endothelial surface was also related to erythrocyte stasis.
This is another reason why 5-HT and other media can cause
vein contraction, leading to an increase in capillary ﬁ ltration
pressure.
There are some views that changes in interstitial tissue
contribute to the formation of burn edema. Lund and his
colleagues found that interstitial hydrostatic pressures are
dramatically reduced in the early post-burn stages, which
may be due to collagen ﬁ ber damage, interstitial space vol-
ume increase, and vacuum effects The negative pressure, in
the region of about 120 mmHg, is so great, and there are
other co-existing factors; thus, it is not difﬁ cult to explain
why the burn wound edema rapidly formed within the
2–3 h after injury.
Characteristics of the Time Course of Burn Wound Edema
It is important to learn the time course of burn edema since
the ability of the tissues to receive oxygen and nutrients is
reduced during this period and susceptibility to infection is
increased. Wound edema is not only limited locally after a
burn, but it also occurred in the tissue far away from the
wound. We [ 13 ] set up 10 % deep second-degree burns in
rats and found that the content of ﬂ uid in the wound tissue
was signiﬁ cantly higher than normal at 6, 24, and 48 h after
injury, while it had returned to normal by 72 h post-injury.
The content of ﬂ uid in the adjacent wound tissue was also
higher than the normal value on 6, 24 h after the injury, but
the swelling decreased quickly, and returned to normal by
48 h after the injury. The experimental results are shown in
Table 9.1 .
9.1 Characteristics of Burn-Wound Healing

212
Prothrombotic State
Coagulation, anticoagulation and ﬁ brinolysis changes occur
immediately after burns, which showed blood hypercoagula-
bility, otherwise called the prothrombotic state. Many stud-
ies suggest that the phenomenon of progressive burn wound
deepening is closely related to the prothrombotic state.
Clinical Evidence of Blood Hypercoagulability in the Early
Stages of Burns
We [ 14 ] detected 21 indicators for blood coagulation, antico-
agulation, ﬁ brinolysis, and platelet in 78 patients with mild,
moderate, severe, and extraordinarily severe burns and found
that: the patient is in a prothrombotic state during the early
stages of burns. The results were shown in Tables 9.2 , 9.3 ,
9.4 , and 9.5 . A comprehensive analysis of these indicators
can be categorized as the following characteristics:
1. Blood-clotting factor (Fg: Ag, VWF: Ag) increased
2. Anticoagulant weakened, (AT-III: a, AT-III: Ag, FPS
decreases, and PC: a drop in the extraordinarily severe group)
3. Insufﬁ cient ﬁ brinolytic function: the ﬁ brinolytic system
was activated owing to an increase in ﬁ brin degradation
products (FDP) and formation of kallikrein, and led to
PLG: Ag increases, which can be regarded as a protective
anti-injury reaction. However, ﬁ brinolytic activity was
reduced because of an increase in PAI: Ag; thus, the body
still has a relatively insufﬁ cient ﬁ brinolytic function
4. TXB2 increased signiﬁ cantly, PGF1α was reduced sig-
niﬁ cantly, indicating platelet activation, vascular endo-
thelial injury, thus contributing to vasoconstriction,
platelet aggregation; thrombocytopenia related to partici-
pation in micro-thrombus formation, the decline of PAdT,
PagT related to material released from the activated plate-
lets and acidosis
5. Blood viscosity and hematocrit increased.
Clearly, the above-mentioned experimental evidence
has fully demonstrated that during the early stages after a
burn there is an obvious blood hypercoagulability. The
prothrombotic state in peripheral blood may have contrib-
uted to wound microthrombosis. In addition, according to
the above information, there exists a signiﬁ cantly obvious
phenomenon about hypercoagulability in the severe group
and extraordinarily severe group, indicating that the hyper-
coagulable state has a close relationship with the severity
of the burn.
Table 9.1 Dynamic observation of the content of ﬂ uid in the wound and adjacent tissue (g %) N = 5
Post-burn
Normal control
6 h
24 h
48 h
72 h
5 days
7 days
Wound tissue
67.42 ± 1.24
83.47 ± 3.90 #
75.04 ± 1.28**
71.71 ± 1.47 #
68.19 ± 2.49
68.46 ± 1.84
68.02 ± 1.78
Adjacent tissue
71.54 ± 1.88 #
70.13 ± 1.63*
69.81 ± 0.85
68.91 ± 1.69
68.23 ± 1.49
67.46 ± 1.21
Quoted from Zhang Yuangui et al. [ 13 ]
Compared with the controls:* p < 0.05, # p < 0.01
Table 9.2 Blood coagulation index in mild burns patients n
x
s
=
±
(
)
14,

d 1
d 3
d 5
Control
Fg: Ag (%)
114.3 ± 33.7
136.9 ± 42.2***
161.8 ± 28.4***
104.6 ± 19.7
VWF: Ag (%)
180.3 ± 57.2***
210.5 ± 64.7***
190.9 ± 81.2***
94.1 ± 30.1
AT-III: a (%)
62.3 ± 14.0***
63.5 ± 29.1***
71.1 ± 24.4***
90.3 ± 13.2
AT-III: Ag (g/L)
260.2 ± 71.0
311.1 ± 32.1
223.1 ± 114.3
290.0 ± 30.0
PC: Ag (g/L)
82.33 ± 21.9
98.09 ± 26.1
82.66 ± 33.2
33.2 ± 7.5
TPS (%)
73.5 ± 6.5***
101.8 ± 11.9
114.6 ± 24.1
97.6 ± 9.8
FPS (%)
52.5 ± 24.2***
74.1 ± 35.0
64.3 ± 13.1
100.9 ± 29.1
PAI: a (IU/ml)
9.3 ± 6.6
7.3 ± 3.0
9.0 ± 2.2*
6.4 ± 2.6
PLG: Ag (g/L)
242.8 ± 39.1*
254.4 ± 73.8
271.0 ± 48.3
281.0 ± 51.5
FDP (mg/L)
28.9 ± 26.1***
19.6 ± 18.2**
15.0 ± 21.6
9.7 ± 3.5
BPC (×10 9 )
144.0 ± 40.1
138.9 ± 70.5
92.0 ± 10.7***
171.1 ± 35.7
TXB 2 (μg/L)
311.3 ± 291.8*
593.9 ± 112.1***
1035.5 ± 623.5***
136.0 ± 81.9
6-keto-PG 1 (μg/L)
23.3 ± 15.2***
43.7 ± 9.1***
41.7 ± 9.7***
120.8 ± 16.6
PAdT (%)
58.4 ± 15.6
53.2 ± 8.8***
65.5 ± 6.4
62.0 ± 4.7
PAgT (%) (ADP0.5 μm)
2 min
26.3 ± 18.7
8.7 ± 4.7
13.6 ± 0**
30.7 ± 9.3
4 min
33.3 ± 24.7
8.7 ± 4.7**
11.1 ± 0*
30.7 ± 12.5
HCT (%)
41.56 ± 6.70
42.62 ± 5.39
34.21 ± 4.81***
40.8 ± 5.3
Blood viscosity ( r = 153.6/s)
7.2 ± 3.9**
8.5 ± 2.0***
8.0 ± 3.5***
5.3 ± 0.52
Quoted form Sun Zhen et al. [ 14 ]
Compared with the control group: * p < 0.05; ** p < 0.01; *** p < 0.001
9 Burn Wound Healing

213
Characteristics of Anticoagulant and Fibrinolytic Function in
Peripheral Blood and Local Wounds and Their Relationship
with Progressive Burn Deepening
Recent research [ 15 , 16 ] into deep second-degree burns in
rats found that the level of plasma AT-III: a was signiﬁ cantly
lower than in the control group at 6, 24, and 48 h after injury.
The level of plasma tPA: a was signiﬁ cantly higher, while the
PLG: a was signiﬁ cantly lower at 2 h after injury, suggesting
that activation of the ﬁ brinolytic response might have been
accompanied by increased anti-ﬁ brinolytic function. The
duration of the confrontation between ﬁ brinolysis and anti-
ﬁ brinolytic function was not long. The level of tPA: a was
down to normal at 24 h after injury, while the PLG: a was still
at a low level. The level of α 2-AP: a was also elevated and
continued until 10 days after injury, suggesting a dominant
role in anti-ﬁ brinolysis. The level of plasma FDP was lower
Table 9.3 Blood coagulation index in moderate burns patients n
x
s
=
±
(
)
13,

d 1
d 3
d 5
Control
Fg: Ag (%)
86.0 ± 22.9
102.2 ± 14.0
89.0 ± 16.8
104.6 ± 19.7
VWF: Ag (%)
200.4 ± 61.6***
238.1 ± 60.0***
240.6 ± 48.0***
94.1 ± 30.1
AT-III: a (%)
81.2 ± 27.5
70.9 ± 18.3***
76.9 ± 16.9***
90.3 ± 13.2
AT-III: Ag (g/L)
216.6 ± 71.7***
232.8 ± 81.6***
243.5 ± 58.3***
290.0 ± 30.0
PC: Ag (g/L)
25.4 ± 15.4*
24.7 ± 6.9***
28.3 ± 7.9
33.2 ± 7.5
TPS (%)
91.7 ± 13.5
94.1 ± 16.3
99.9 ± 19.7
97.6 ± 9.8
FPS (%)
80.8 ± 21.4
83.0 ± 26.9
78.1 ± 31.4
100.9 ± 29.1
PAI:a (IU/ml)
8.9 ± 3.2*
8.4 ± 4.8
10.78 ± 4.44***
6.4 ± 2.6
PLG: Ag (g/L)
200.2 ± 75.8***
213.7 ± 51.0**
289.7 ± 133.2
281.0 ± 51.5
FDP (mg/L)
24.4 ± 25.6***
34.6 ± 53.3*
18.6 ± 14.9**
9.7 ± 3.5
BPC (×10 9 )
114.2 ± 50.6***
117.3 ± 59.1***
115.4 ± 44.1***
171.1 ± 35.7
TXB 2 (μg/L)
114.2 ± 50.6***
117.3 ± 59.1***
115.4 ± 44.1***
136.0 ± 81.9
6-keto-PG1 α (μg/L)
47.0 ± 12.3***
81.4 ± 80.2**
29.3 ± 19.7**
120.8 ± 16.6
PAdT (%)
57.9 ± 8.4*
61.1 ± 6.3
59.4 ± 7.3
62.0 ± 4.7
PAgT (%) (ADP
0.5 μm)
2 min
14.3 ± 8.8***
11.6 ± 6.5***
10.8 ± 7.6***
30.7 ± 9.3
4 min
12.3 ± 7.1***
10.9 ± 5.8***
11.2 ± 9.2***
30.7 ± 12.5
HCT (%)
47.9 ± 6.7***
45.6 ± 6.2*
39.2 ± 6.2
40.8 ± 5.3
Blood viscosity ( r = 153.6/s)
8.5 ± 2.0***
8.7 ± 1.7***
8.5 ± 2.0***
5.3 ± 0.52
Quoted from Sun Zhen et al. [ 14 ]
Compared with the control group: * p < 0.05, ** p < 0.01, *** p < 0.001
Table 9.4 Blood coagulation index in severe burns patients n
x
s
=
±
(
)
17,

d 1
d 3
d 5
Control
Fg: Ag (%)
136.1 ± 54.2***
172.2 ± 40.6***
176.4 ± 41.8***
104.6 ± 19.7
VWF: Ag (%)
230.2 ± 56.3**
243.4 ± 91.1***
245.8 ± 76.4**
94.1 ± 30.1
AT-III: a (%)
65.3 ± 16.2***
73.4 ± 16.1***
74.0 ± 19.5***
90.3 ± 13.2
AT-III: Ag (g/L)
204.2 ± 57.3***
209.5 ± 51.5***
248.9 ± 65.9***
29.0 ± 30.0
PC: Ag (g/L)
22.3 ± 7.6***
22.3 ± 7.8***
24.2 ± 7.2***
33.2 ± 7.5
TPS (%)
78.1 ± 1.8***
91.8 ± 23.8***
102.6 ± 20.5***
97.6 ± 9.8
FPS (%)
62.2 ± 15.7**
75.1 ± 13.0**
67.7 ± 17.0***
100.9 ± 29.1
tPA: a (IU/ml)
1.9 ± 1.9
2.3 ± 1.5
2.2 ± 2.2
1.9 ± 0.72
PAI: a (IU/ml)
150.1 ± 56.0***
11.2 ± 8.5*
13.5 ± 6.0***
6.4 ± 2.6
PLG: Ag (g/L)
11.4 ± 7.0**
177.3 ± 76.8***
242.5 ± 99.6
281.0 ± 51.5
FDP (mg/L)
30.6 ± 26.7***
28.7 ± 26.0***
17.1 ± 13.8**
9.7 ± 3.5
BPC (×10 9 )
92.7 ± 50.0***
75.1 ± 27.8***
86.8 ± 26.6***
171.1 ± 35.7
TXB 2 (μg/L)
770.9 ± 528.2***
1043.6 ± 452.6***
1171.8 ± 392.0***
136.0 ± 81.9
6-keto-PG1 α (μg/L)
23.3 ± 11.7***
45.1 ± 36.2***
49.4 ± 44.3**
120.8 ± 16.6
PAdT (%)
62.3 ± 6.9
55.1 ± 6.0***
57.8 ± 8.5*
62.0 ± 4.7
PAgT (%) (ADP
0.5 μm)
2 min
10.1 ± 4.6***
15.72 ± 13.82***
13.71 ± 7.59***
30.7 ± 9.3
4 min
9.75 ± 2.86***
10.01 ± 4.62***
12.70 ± 1.30***
30.7 ± 12.5
HCT (%)
51.12 ± 8.11***
48.90 ± 7.33***
41.38 ± 6.68
40.8 ± 5.3
Blood viscosity ( r = 153.6/s)
9.88 ± 3.26***
8.65 ± 1.86***
8.48 ± 3.40***
5.3 ± 0.52
Quoted from Sun Zhen et al. [ 14 ]
Compared with the control group: * p < 0.05, ** p < 0.01, *** p < 0.001
9.1 Characteristics of Burn-Wound Healing

214
from 72 h after the injury until 10 days after injury, indicat-
ing that the anti-ﬁ brinolytic role was further strengthened.
Similarly, at 2 h after injury, the detection of ﬁ brinolytic
function in wound tissue at 2 h after injury is also reﬂ ected
in the fact that plasminogen activation was associated with
response to anti-ﬁ brinolytic enhancement phenomenon,
which manifested as the elevated level of FDP, tPA: a, and
PAI: a. However, this phenomenon is reversed at 24 h after
injury, showing FDP levels continuing to decrease and PAI:
a, α 2-AP: a continuing to rise. The results are shown in
Tables 9.6 , 9.7 , 9.8 , 9.9 , and 9.10 . The results showed that
ﬁ brinolysis was activated in the wound at 2 h after burns, but
Table 9.5 Blood coagulation index in extraordinarily severe burns patients n
x
s
=
±
(
)
34,

d 1
d 3
d 5
Control
Fg: Ag (%)
123.0 ± 44.9**
162.0 ± 57.2**
210.46 ± 44.16***
104.6 ± 19.7
VWF: Ag (%)
261.3 ± 78.6**
295.6 ± 123.4**
310.6 ± 67.53***
94.1 ± 30.1
AT-III: a (%)
65.0 ± 17.4***
58.3 ± 17.4***
65.33 ± 17.98***
90.3 ± 13.2
AT-III: Ag (g/L)
180.6 ± 62.2***
182.4 ± 48.4***
200.1 ± 44.7***
290.0 ± 30.0
PC: a (%)
63.7 ± 32.2***
59.5 ± 29.5***
59.38 ± 24.89***
91.0 ± 12.7
PC: Ag (g/L)
21.5 ± 7.6***
20.2 ± 7.4***
20.8 ± 8.6***
33.2 ± 7.5
TPS (%)
78.8 ± 17.2***
79.6 ± 16.0***
91.9 ± 19.0***
97.6 ± 9.8
FPS (%)
62.3 ± 24.0**
65.5 ± 21.2***
70.2 ± 18.7**
100.9 ± 29.1
tPA: a (IU/ml)
2.5 ± 2.0
2.3 ± 1.8
2.9 ± 2.0
1.9 ± 0.72
PAI: a (IU/ml)
10.9 ± 5.9**
8.2 ± 5.3
9.9 ± 5.7**
6.4 ± 2.6
PLG: Ag (g/L)
132.2 ± 43.7***
116.5 ± 45.6***
161.5 ± 59.7
281.0 ± 51.5
FDP (mg/L)
31.9 ± 23.2***
34.4 ± 35.2
26.7 ± 30.4
9.7 ± 3.5
BPC (×10 9 )
95.1 ± 39.6***
74.1 ± 23.5***
76.6 ± 30.4***
171.1 ± 35.7
TXB 2 (μg/L)
1182.6 ± 458.7***
1043.6 ± 452.6***
1171.8 ± 392.0***
136.0 ± 81.9
6-keto-PG1 α (μg/L)
25.7 ± 24.9***
48.5 ± 53.0***
23.4 ± 22.1***
120.8 ± 16.6
PAdT (%)
55.9 ± 7.9***
57.0 ± 8.8**
53.3 ± 8.3***
62.0 ± 4.7
PAgT (%) (ADP
0.5 μm)
2 min
9.85 ± 4.4***
9.7 ± 5.5***
9.5 ± 5.5***
30.7 ± 9.3
4 min
10.9 ± 5.2***
9.5 ± 5.8***
8.6 ± 5.3***
30.7 ± 12.5
HCT (%)
53.65 ± 9.28***
52.3 ± 8.6***
45.9 ± 10.1**
40.8 ± 5.3
Blood viscosity ( r = 153.6/s)
10.43 ± 3.03***
10.2 ± 2.9***
9.6 ± 3. 0***
5.3 ± 0.52
Quoted from Sun Zhen et al. [ 14 ]
Compared with the control group: * p < 0.05, ** p < 0.01, *** p < 0.001
Table 9.6 Dynamic changes in wound and plasma fibrin degradation products (FDPs) in deep second-degree burn wounds in rats
(μg/ml) of x
s
±
(
)
Control
Time after injury
2 h
24 h
72 h
10 days
Wound
( n = 7)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
1.52 ± 0.15
2.35 ± 0.17***
1.70 ± 0.15
0.60 ± 0.49***
0.58 ± 0.27***
Plasma
( n = 12)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
2.45 ± 0.40
2.10 ± 0.62
2.00 ± 0.65
1.45 ± 1.05**
1.96 ± 0.54
Quoted from Fang Pei-yao et al. [ 15 ]
Compared with the controls: * p < 0.05, ** p < 0.01, *** p < 0.001
Table 9.7 Dynamic changes in wound and plasma plasminogen (PLG): a in deep second-degree burns in rats (IU ×10 −2 /ml) x
s
±
(
)
Control
Time after injury
2 h
24 h
72 h
10 days
Wound
( n = 6)
( n = 6)
( n = 6)
( n = 5)
0.06 ± 0.03
0.14 ± 0.03***
0.60 ± 0.49***
0.58 ± 0.27***
Plasma
( n = 12)
( n = 3)
( n = 6)
( n = 6)
( n = 4)
1.11 ± 0.15
0.79 ± 0.35*
0.87 ± 0.10**
1.17 ± 0.25
1.14 ± 0.15
Quoted from Fang Pei-yao et al. [ 15 ]
Compared with control:* p < 0.05, ** p < 0.01, *** p < 0.001
9 Burn Wound Healing

215
the ﬁ brinolysis was in a suppression state at 24 h after injury,
and continued until 10 days after injury, indicating that ﬁ bri-
nolysis inhibition may be caused by signiﬁ cantly enhanced
activity of plasminogen activator inhibitor during the early
stages of burns as well as signiﬁ cantly enhanced activity of α
2-antiplasmin starting at 24 h after injury.
The changes in the ﬁ brinolytic response to a burn injury
may be related to the self-adjustment process in the body.
Fibrinolytic response was activated immediately after the
burn, and at the same time, the wound PAI: A was enhanced,
peripheral α2-antiplasmin activity was enhanced, PLG: A
was raised, wound FDP had fallen, suggesting the body’s
inhibitory regulation response to wound-activated ﬁ brinoly-
sis. This regulation is conducive to local ﬁ brin deposition in
the wound and, along with the coagulation factor and cal-
cium ions, forms a cross-linked network to prevent bacterial
invasion through adhesion, and may attract inﬂ ammatory
cells to play a role in sterilization and participate in wound
healing. However, a large amount of localized ﬁ brin deposi-
tion allows stasis of the microcirculation of the wound,
resulting in tissue ischemia and necrosis to a progressively
deepening wound. The reason for increased AT-III: A in the
deepening wound at 72 h after injury is the host regulatory
feedback for the large amount of ﬁ brin deposition in the local
wound to avoid excessive ﬁ brin deposition. At the same
time, localized deposition of ﬁ brin was able to provide pro-
tection by inhibiting plasminogen. In addition, the study also
found that after a burn the anticoagulant and ﬁ brinolytic
function in a variety of regulatory mechanisms of the changes
coincided with the histological ﬁ ndings on local micro-
thrombus formation and Masson staining in the degeneration
of the expanded collagen area. Ehrlich found that the vessels
were reconnected in the scalded rats by using ﬁ brin
decomposition to reduce ﬁ brinogen in the blood vessels. The
study further conﬁ rmed the changes in anticoagulant ﬁ brino-
lytic function as the burn was not enough to dissolve the
Table 9.8 Dynamic changes of wound and plasma tPA: A (IU/ml) and PAI: A (IU/ml) in deep second-degree burns in rats x
s
±
(
)
Time after injury
Index
Sample
Control
2 h
24 h
72 h
10 days
tPA: A
Wound
( n = 7)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
0.09 ± 0.08
0.30 ± 0.05**
0.33 ± 0.04***
0.38 ± 0.12***
0.29 ± 0.11***
Plasma
( n = 12)
( n = 4)
( n = 6)
( n = 6)
( n = 4)
0.53 ± 0.22
0.82 ± 0.15*
0.69 ± 0.24
0.74 ± 0.29
0.65 ± 0.14
PAI: A
Wound
( n = 7)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
0.23 ± 0.03
0.43 ± 0.05***
0.34 ± 0.06**
0.31 ± 0.06**
0.33 ± 0.07**
Plasma
( n = 12)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
0.84 ± 0.25
0.88 ± 0.17
0.80 ± 0.24
0.99 ± 0.12
1.15 ± 0.17*
Quoted from Fang Pei-yao et al. [ 15 ]
Compared with the controls: * p < 0.05, ** p < 0.01, *** p < 0.001
Table 9.9 Dynamic changes in wound and plasma α 2 -AP: A (%) x
s
±
(
)
Time after injury
Sample
Control
2 h
24 h
72 h
10 days
Wound
( n = 6)
( n = 4)
( n = 6)
( n = 4)
( n = 5)
1.66 ± 4.08
6.75 ± 8.30
23.00 ± 12.46**
16.17 ± 11.72*
9.40 ± 6.99
Plasma
( n = 12)
( n = 4)
( n = 6)
( n = 6)
( n = 4)
58.83 ± 25.20
62.18 ± 25.22
100.50 ± 9.44**
105.60 ± 14.57***
93.25 ± 9.18*
Quoted from Fang Pei-yao et al. [ 15 ]
Compared with the controls: * p < 0.05, ** p < 0.01, *** p < 0.001
Table 9.10 Dynamic changes in wound and plasma AT-III: A (%) x
s
±
(
)
Control
Time after injury
2 h
24 h
72 h
10 days
( n = 12)
( n = 4)
( n = 6)
( n = 6)
( n = 5)
83.47 ± 15.04
0.79 ± 0.35
89.72 ± 19.22
111.76 ± 16.02*
79.33 ± 27.25
(Quoted from Fang Pei-yao et al. [ 15 ]
Compared with the controls: * p < 0.01
9.1 Characteristics of Burn-Wound Healing

216
local ﬁ brin, thus becoming an important factor for the early
stages of wound deepening.
In addition, the burn complement, kinin, bradykinin sys-
tem activation, and histamine release further affect the
microvascular function, which is also an important factor in
the mechanism of progressive wound deepening.
Local Wound Inﬂ ammation
Inﬂ ammation begins immediately after the burn causes the
local wound, which is regarded as the startup phase in the
process of wound healing, and is necessary for wound heal-
ing, but an inﬂ ammatory response that is too strong may
cause local damage, leading to progressive damage.
Mechanism of Inﬂ ammatory Damage to the Local Wound
Complement, kinin/bradykinin, coagulation, and ﬁ brino-
lytic systems can be activated and then stimulate cells in
the blood circulation to release a variety of cytokines and
inﬂ ammatory mediators, thereby constituting a complex
interaction of networks. Data showed that the number of
inﬂ ammatory cells and neutrophils in peripheral blood
was signiﬁ cantly increased at 4 h after the burn, while the
peak expression of the CD11/CD18 molecules represent-
ing neutrophil activation had emerged at half an hour after
injury, with emergence of a second peak at 24 h, as shown
in Table 9.11 . It suggested that the activation of neutrophil
occurs during the early stages of burns. Recent work [ 18 ] has
shown that the release of inﬂ ammatory mediators in skin tis-
sue after burns are regional and targeted, and are expressed
as large differences in the level of IL-8 release among the
burn wound tissue, the wound margin, and normal skin tis-
sue (54.59 ± 12.44 ng/ml, 3.01 ± 1.62 ng/ml, 1.56 ± 1.33 ng/
ml respectively). This suggests that the high level of IL-8
release in this region of burn wounds might occur so that the
host can attract and effect chemotaxis of inﬂ ammatory cells.
It is a self-regulatory mechanism so that the host can resist
microbial invasion and start the wound healing process. In
addition, many references also show that the level of IL-1,
IL-6, IL-8, TNFα, C3a, C5a, and other inﬂ ammatory media-
tors in local wound tissue were signiﬁ cantly increased dur-
ing the early stages of the burn. Cytokines and inﬂ ammatory
mediators attract neutrophils and macrophages arriving in
the local wound, and both types of cells ﬁ rst adhere to vas-
cular endothelial cells, are extravasated and then release
oxygen free radicals and proteolytic enzymes in the wound
tissue that can lead to the tissue damage. The matter of
neutrophils adhesion to endothelial cells is a key process
for inﬂ ammatory cell extravasation. When the blood ﬂ ow
slows down, the neutrophil rolling on the vessel wall
adheres to the vascular endothelial cell via its surface mol-
ecule LECAM-selectin binding to the corresponding ligand
ECAM. However, this adhesion is unstable; unless the neu-
trophils surface molecule CD11/CD18 binds to ICAM-1,
neutrophils can become ﬁ rmly attached to the vessel wall.
With the roles of proteolytic enzyme hydrolysis, adhesion
molecules, and intracellular adhesion molecule connected
within the frame structure changes, neutrophils extravasate
out of the vessels into the tissue space. High expression of
CD11/CD18 on the neutrophils surface will help cell inﬁ l-
tration during the early stages of the burn. Myeloperoxidase
(MPO) is the characteristic enzyme of polymorphonuclear
neutrophils (PMNs). Tissue MPO activity can indirectly
reﬂ ect the number of PMNs. the number of PMNs was
signiﬁ cantly increased in the wound in a rat with a deep
second-degree burn as local MPO activity was detected at
24 h after injury, as shown in Table 9.12 . Local inﬁ ltration
of activated neutrophils was found to have grown at 4 h
post-burn, reaching the peak at 24 h post-burn, by means of
immunohistochemistry to observe CD11/CD18 cell surface
molecule expression. Meanwhile, malondialdehyde (MDA),
the end product of oxygen free radical chain reaction, was
signiﬁ cantly higher at 48 h after the burn (see Table 9.12 ),
indicating that the neutrophil respiratory burst was enhanced
in the local wound, and the release of oxygen free radicals
increased. Although, as shown in Table 9.12 , superoxide
dismutase activity was increased in wound tissue, collagen
degeneration and necrosis were increased, and expression of
vimentin antigens was reduced (see Table 9.13 ), suggesting
that neutrophil activation that is too strong, and local inﬁ l-
tration and oxygen free radicals damage to tissue exceeds
the body’s antioxidant and other protective mechanisms,
leading to progressive wound damage.
Table 9.11 The number of neutrophils and expression of CD11/CD18 in peripheral blood in rats with deep second-degree burns
Post-burn time
Control
0.5 h
4 h
24 h
48 h
PMNs number
0.0917
0.7700*
1.7100**
0.8222**
0.4778
(10 9 /L)
±0.0588
±0.4688
±0.7894
±0.6515
±0.2048
CD11/CD18
66.61
94.50**
88.30**
94.73**
89.47**
(%)
±9.21
±3.04
±7.42
±3.97
±4.58
Cited in Wang Shijun et al. [ 17 ]
PMNs polymorphonuclear neutrophils
Compared with the controls: * p < 0.05, ** p < 0.01
9 Burn Wound Healing

217
Several chapters of this book have described in detail an
appropriate inﬂ ammatory response necessary for wound
healing, while insufﬁ cient or excessive inﬂ ammatory
responses cause wound healing, “out of control,” that is, a
bad prognosis for wound healing delay or progressive wound
deepening. How do we deﬁ ne “moderate inﬂ ammatory reac-
tion”? How do we quantify the “inﬂ ammatory response is
inadequate or too strong?” The answer to these questions
helps us to grasp regulation of the inﬂ ammatory response for
a good prognosis for wound healing.
Effect of Necrotic Tissue on Local Inﬂ ammatory Reaction
and Its Relationship with Progressive Wound Deepening
Progressive wound deepening was related to strong local
inﬂ ammation. The presence of necrotic tissue is the most
important reason for a strong local inﬂ ammatory reaction.
Skin tissue can synthesize lipoprotein complex toxic sub-
stances immediately after burns, which cause damage to tis-
sue cells. It was found that a large amount of necrotic tissue
can activate the macrophages, lymphocytes, and neutrophils,
releasing oxygen free radicals, lysosomal enzymes, cyto-
kines, prostaglandins, leukotrienes, and other media. In vitro
experiments also conﬁ rmed that the scald skin contains not
only TNFα and other inﬂ ammatory mediators, and its leach-
ing solution can also damage cultured vascular endothelial
cells. A large number of inﬂ ammatory mediators released
from necrotic tissue are not only able to further activate local
inﬂ ammatory cells to produce excessive inﬂ ammatory
reaction but also directly or indirectly damage the remaining
wound edge and wound tissue repair cells, such as ﬁ bro-
blasts, endothelial cells, and keratinocytes, and prevent these
repair cells from migrating to the wound and inhibit wound
healing. In addition, the necrotic tissue present in the wound
can be a good culture medium for bacteria to increase the
wound infection, and increase the local inﬂ ammatory
response.
If burn wound surgery was delayed, the persistence of
necrotic tissue can increase the local inﬂ ammatory response,
deepen the wound, and delay healing. In recent years, a clini-
cal study [ 19 ] found that if the deep second-degree burn
wounds, such as necrotic tissue, were retained until
10–14 days after injury, local IL-8 levels were signiﬁ cantly
higher, reaching 65.80 ± 21.00 ng/ml. A large amount of local
tissue granulocyte inﬁ ltration, a dramatic increase of inﬂ am-
matory response, a signiﬁ cantly expanded necrotic area, and
the scope of the original remnants of the skin appendage dis-
appeared, leading to progressive wound deepening and
delayed wound healing. While the clinical routine tangential
excision surgery was carried out at 3–5 days after injury, the
local release of IL-8 levels (15.28 ± 8.68 ng/ml) was signiﬁ -
cantly reduced at 10–14 days after injury compared with
those (54.59 ± 12.44 ng/ml) before tangential excision sur-
gery at 3–5 days post-burn, the extent of neutrophil inﬁ ltra-
tion and inﬂ ammatory responses were reduced, the remnants
of the skin appendage retained, and the progressive wound
deepening reduced compared with the persistent necrosis
Table 9.12 Dynamic observation of myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, superoxide dismutase (SOD) activity in
deep second-degree scald wounds in rats
Post-burn time
Control
0.5 h
4 h
24 h
48 h
MPO activity
0.2019
0.1748
0.1899
2.2089**
0.9480**
10 U/L
±0.0413
±0.0518
±0.0137
±0.0463
±0.0710
MDA content
53.37
28.94**
53.13 ##
59.61
65.96*
nmol/ml
±16.02
±3.87
±19.87
±12.27
±17.01
SOD activity
372.43
258.70**
370.52 ##
402.08*
442.01**
NU/ml
±28.66
±33.10
±32.31
±27.89
±20.58
Cited in Wang Shijun et al. [ 17 ]
Compared with the controls: * p < 0.05, ** p < 0.01
Compared with the previous time point: ## p < 0.01
Table 9.13 Morphological analysis of Masson staining and anti-vimentin staining in deep second-degree scald wounds in rats
Post-burn time
Control
0.5 h
4 h
24 h
48 h
Denatured
0
0.01
0.33**
0.50**
1.21**
Collagen area/mm 2
±0.01
±0.07
±0.03
±0.07
Necrosis cells/mm 2
0
0.03
0.26**
0.63**
1.14**
±0.02
±0.03
±0.05
±0.04
Cited in Wang Shijun et al. [ 17 ]
Compared with group: * p < 0.05, ** p < 0.01
9.1 Characteristics of Burn-Wound Healing

218
wound. At the same time, local levels of EGF, PDGF-AB,
basic ﬁ broblast growth factor (bFGF), and other growth fac-
tors rose, new local capillary formation and new collagen pro-
duction occurred, and rapid epithelization. The results are
shown in Tables 9.14 , 9.15 , and 9.16 .
In addition, the study [ 20 ] also found that the release of IL-8
was signiﬁ cantly increased at 3–5 days after injury before the
tangential excision surgery compared with normal skin and
wound edge skin tissue, and local high concentrations of IL-8
may attract neutrophils inﬁ ltrating the wound tissue. Therefore,
the inﬂ ammatory response can be seen obviously in histologi-
cal wound observation before tangential excision surgery. With
the course of evolution, by observing the wound histology, the
area of necrotic tissue that was dyed red with the Masson stain
was further expanded, while the bright green area of the normal
tissue was reduced. At the same time, vimentin antigen-posi-
tive cells were signiﬁ cantly reduced, suggesting that progres-
sive wound tissue necrosis occurred. This may be due to the
persistence of necrotic tissue, and the high expression of IL-8,
etc., so that further neutrophil chemotaxis is being activated.
Neutrophils adhere to vascular endothelium through the CD18
receptor, and other relevant expression of adhesion molecules
in vascular endothelium. Neutrophils release oxygen free radi-
cals to damage vascular endothelium, leading to thrombosis,
causing progressive wound deepening. However, after surgical
removal of the wound by tangential excision of necrotic tissue,
the histological changes mentioned above can be signiﬁ cantly
reversed, which further conﬁ rmed that the presence of a
necrotic tissue burn wound could induce an excessive local
inﬂ ammatory response, leading to the occurrence of progres-
sive wound damage.
9.1.3.3 Prevention and Management
for Progressive Wound Deepening at
an Early Stage After a Burn
In the past few decades, scientists have studied the phenom-
enon of progressive wound deepening at an early stage post-
burn, carrying out extensive means of prevention and
treatment research, for example, they used anticoagulant, a
drug that promotes ﬁ brinolysis and improves the local wound
inﬂ ammatory response to prevent progressive wound deep-
ening, which has shown signiﬁ cant progress and good pros-
pects. However, some research evidence was only from
animal experiments or from clinical use without permission
to use experimental reagents, etc.; thus, it is still a consider-
able distance from practical clinical application. This section
focuses on clinical drug or treatments that were directly used
for progressive wound damage in deep second-degree burns.
Table 9.15 Effects of necrotic tissue on local inﬂ ammation
Group
( n = 7)
Degree of inﬂ ammation
−
+
++
+++
Necrotic tissue group
0
0
1
6
Preoperative group
0
1
6
0
Tangential group
0
7
0
0
Cited in Shu-Liang Lu et al. [ 20 ]
+ indicates the extent of new granulation tissue formation and epidermal repair
Table 9.16 Effects of necrotic tissue on tissue repair
Group
( n = 7)
Formation of new granulation
Epidermal repair
−
+
++
+++
−
+
++
+++
Necrotic tissue group
7
0
0
0
7
0
0
0
Preoperative group
7
0
0
0
6
1
0
0
Tangential group
1
3
1
2
3
1
1
2
Cited in Shu-Liang Lu et al. [ 20 ]
+ indicates the extent of new granulation tissue formation and epidermal repair
Table 9.14 The release of growth factor levels in local wounds pg ml x
s
/
,
+
(
)
Group
( n = 7)
EGF
bFGF
PDGF-AB
Necrotic tissue group
4.06 ± 3.73***
108.89 ± 36.63***
60.07 ± 19.55*
Preoperative group
2.27 ± 1.05***
103.22 ± 37.49**
49.73 ± 11.25***
Tangential group
150.30 ± 9.27
173.97 ± 24.65
91.60 ± 21.97
Cited in Shu-Liang Lu et al. [ 20 ]
EGF epidermal growth factor, bFGF basic ﬁ broblast growth factor, PDGF platelet-derived growth factor
Tangential excision compared with the control group: * p < 0.05, ** p < 0.01, *** p < 0.005
9 Burn Wound Healing

219
Improve the Prothrombotic State Post-burn
The natural evolution of the progressive reduction of blood
ﬂ ow was observed in deep second-degree burn wounds, lead-
ing to ischemia and further necrosis, which would delay
wound healing; thus, the phenomenon has a certain relation-
ship with micro-thrombosis formation. Therefore, the early
use of anticoagulant drugs post-burn is possible to improve
the prothrombotic state, thereby reducing micro-thrombus
formation, improving microcirculation to make a good blood
supply and avoid further necrosis.
Application of Anticoagulant Fibrinolytic Drugs
1. The Heparin-Like Compounds: Heparin, a highly sulfated
glycosaminoglycan, is widely used as an injectable anti-
coagulant. Heparin is a polymer with a molecular weight
ranging from 12 to 15 kDa. Heparin does not easily inﬁ l-
trate the wound tissue, and the half-life is short; as a topi-
cal wound treatment it is not of great value. It is not safe
for systemic use owing to bleeding complications. Dum
found that low molecular weight heparin and heparin-like
substances (heparin) are low molecular weight fragments
of a heparin by enzymatic or chemical degradation whose
molecular weight ranged from 3,000 to 10,000. Heparinoid
is a natural, synthetic or semi-synthetic class of com-
pounds that has a similar effect to heparin, a molecular
weight of 6,000. There is no clear boundary among hepa-
rin and low molecular weight heparin, heparinoid, collec-
tively referred to as heparin-like compounds. The main
ingredients of heparinoid are glycosaminoglycans, which
have a similar structure and biological effect to heparin.
The effect of anticoagulant was achieved through hepari-
noid combined with AT-III and heparin cofactor II. AT-III
can inhibit thrombin-activated factors, including throm-
bin, coagulation factor Xa, IXa, XIa, and XIIa, mainly the
inhibition of thrombin and coagulation factor Xa.
Heparinoid anticoagulant activity is much stronger than
that of heparin, while its rate of bleeding complications is
low, and the formation of the thrombin AT-III and throm-
bin–coagulation factor Xa complex through the effect of
heparinoid was 1,000 times faster than heparin. It can pro-
mote ﬁ brinolysis through the activation of plasminogen
and shortens euglobulin dissolution time. The half-life of
heparinoid is longer than heparin and its molecular weight
is smaller. It is easy for heparinoid to penetrate tissues
when topically applied without the tendency toward sys-
temic bleeding. In addition, it was found that heparin is
composed of cell membrane and extra-cellular matrix,
also related to the components of synthesis for cell mem-
brane and matrix. Heparin takes part in the formation of
the cytoskeleton to control cell–cell, cell–matrix, and cell
shape and movement, and to inﬂ uence cell proliferation.
In vivo a variety of growth factors such as FGF, EGF,
ECGF, etc., are of heparin-binding form, and these growth
factors in this form combine receptors to promote the bio-
logical effects of wound healing. Therefore, low molecu-
lar weight heparin is gradually being recognized by
clinicians as a topical drug that can improve local blood
supply and promote wound healing.
Plasma AT-III activity was signiﬁ cantly increased in
scalded rat topically treated with heparinoid ointment at
48 h post-burn (Table 9.17 ). FDP levels were signiﬁ cantly
increased in wound tissue at 24 h post-burn (Table 9.18 ),
indicating the enhanced anticoagulant and ﬁ brinolytic
function in the animals. In addition, histological observa-
tions showed expansion of small blood vessels, conges-
tion, hemorrhage, the local micro-thrombus gradually
formed small blood vessels, residual normal hair follicles
decreased, and necrotic tissue deep to the dermis at 6–72 h
Table 9.17 Effect of topical heparin on plasma activity of AT-III
Normal
Time post-burn
6 h
24 h
48 h
72 h
Heparinoid
93.12 ± 14.61
60.46* ± 9.66
65.80* ± 8.29
77.58 # ± 4.05
77.02 ± 7.22
Burn control
93.12 ± 14.61
59.16* ± 14.61
59.24* ± 15.26
57.20* ± 3.81
75.36 ± 7.15
Cited in Zhang Yuangui et al. [ 13 ]
Compared with the normal control group, * p < 0.01
Experimental group and the burn control group, # p < 0.05
Table 9.18 Topical application of heparinoid and FDPs in the burn wounds
Normal
Time post-burn
6 h
24 h
48 h
72 h
Heparinoid
3.79 ± 1.46
30.31 ± 4.93
278.58* # ± 2.14
80.00* ± 1.63
26.39 ± 1.46
Burn control
3.79 ± 1.46
4.35 ± 1.36
63.63** ± 15.26
34.82 ± 5.23
17.41 ± 2.14
Cited in Zhang Yuangui et al. [ 13 ]
Compared with the normal control group, * p < 0.01, ** p < 0.05
Experimental group and the burn control group, # p < 0.05
9.1 Characteristics of Burn-Wound Healing

220
post-burn in the wound tissue of the control group with
scalded rats. Collagen ﬁ bers stained red with Masson’s
stain can be seen gradually increased within 72 h after
injury. While in the experimental group, there were signiﬁ -
cantly fewer wounds of local micro-thrombus formation
and collagen ﬁ bers stained red than in the control group,
and there was normally a higher number of hair follicles
than in the control group. It suggested that topical treat-
ment of heparin might enhance the functions of local anti-
coagulation and ﬁ brinolysis in order to improve local
blood supply, decrease micro-thrombus formation, and
prevent progressive wound deepening. Our study [ 13 ] also
found that heparinoid can promote wound healing, which
was represented as wound tissue hydroxyproline content
being signiﬁ cantly higher (Table 9.19 ), a lower I/III colla-
gen ratio (Table 9.20 ); the fraction of dermal cells to enter
the S-phase increased (Table 9.21 ); the wound healing
time was 20.4 ± 1.4 days, signiﬁ cantly shorter compared
with the control group (22.4 ± 2.1 days). Besides the good
effect on wound healing mentioned above, heparinoid also
has a “secondary effect” with the heparin growth factor in
the promotion of wound healing.
2. Fibrinolysis Preparation: The change in coagulation and
ﬁ brinolysis immediately after a burn is an important fac-
tor leading to progressive wound deepening. Systemic
application of ﬁ brinolysis preparations is a safe and effec-
tive clinical tool for reducing blood viscosity, ﬁ brin depo-
sition, thereby preventing progressive wound deepening.
The ﬁ brinolysis preparation batroxobin was observed to
improve wound healing during the early stages of burns
[ 21 ]. Batroxobin is a serine protease derived from venom,
its polypeptide chain composed of 231 amino acids, with
a molecular weight 36,000. The main mechanism is that it
breaks down ﬁ brinogen in blood, decreasing blood vis-
cosity and ﬁ brin deposition to achieve the purpose of the
prevention and treatment of thrombosis. Scalded rat
experiments found that the high level of ﬁ brin dropped to
normal after the intraperitoneal injection of batroxobin
10 U/kg at 2 h and 24 h post-burn (Table 9.22 ). Collagen
ﬁ bers stained red with Masson’s stain can be seen to grad-
ually increase within 72 h after injury in the control group,
while although the phenomenon of progressive wound
deepening occurs in the batroxobin treatment group, over-
all, there is evidently relief. At the same time, because
local ﬁ brin deposition was reduced and local wound
microcirculation was improved, ischemia and hypoxia
were relieved in the wound, and this led to decreasing
wound deepening. Multiple factors play a role in wound
deepening during the early stages of burns, and batroxobin
only has an effect on improving microcirculation in the
Table 9.19 Effect of topical heparinoid on the content of hydroxyproline in wound tissue (mg/kg) n = 5
Time post-burn
Normal
6 h
24 h
48 h
72 h
5 days
7 days
10 days
14 days
21 days
Heparinoid 19.45 ± 1.76 19.42 ± 1.62 18.97 ± 1.48 20.22 ± 0.60 20.60 ± 2.47
21.54 ± 3.15 21.61 ± 5.10 25.82* # ± 3.41 26.60* ± 2.26 23.54 ± 5.20
Control
19.45 ± 1.76 19.36 ± 1.77 17.64 ± 1.17 17.31 ± 1.50 18.79 ± 1.55
20.94 ± 1.19 21.09 ± 1.55 21.55 ± 3.50
23.32 ± 2.69 26.60* ± 2.89
Cited in Zhang Yuangui et al. [ 13 ]
Compared with the normal control group, * p < 0.01
Experimental group and the burn control group, # p < 0.05
Table 9.20 Effect of topical heparinoid on the ratio of type I/III collagen in burn wounds ( n = 3)
Time post-burn
Normal
3 days
5 days
7 days
10 days
14 days
21 days
Heparinoid
3.625 ± 0.251
3.204 ± 0.392
3.090 ± 0.222
2.923 ± 0.179
2.914 ± 0.221
2.06* ± 0.085
2.58* ± 0.134
Burn Control
3.625 ± 0.251
3.207 ± 0.424
3.050 ± 0.191
3.004 ± 0.298
2.850 ± 0.211
2.760 ± 0.150
2.67* ± 0.193
Cited in Zhang Yuangui et al. [ 13 ]
Compared with the normal control group, * p < 0.01
Table 9.21 Effect of topical heparinoid on the percentage of S phase cells in dermal wounds
Normal
Time post-burn
3 days
5 days
7 days
10 days
14 days
21 days
Heparinoid
9.67 ± 1.72
21.1 ± 2.1
25.2 ± 2.5
36.1* ± 1.0
45.2* ± 4.9
40.5* # ± 7.9
38.8* # ± 7.8
Control
9.67 ± 1.72
21.4 ± 2.6
25.0 ± 2.1
33.2* ± 4.7
39.8* ± 3.7
27.7* # ± 1.8
26.9* # ± 3.5
Cited in Zhang Yuangui et al. [ 13 ]
Compared with the normal control group, * p < 0.01
Experimental group and the burn control group, # p < 0.05
9 Burn Wound Healing

221
dermis. If combined with other blocks, such as a blocker
of neutrophils and oxygen free radicals, better results will
be achieved.
Batroxobin improves post-burn hypercoagulability and
promotes wound healing. Twelve patients with 10–30 %
second-degree burns were given intravenous infusion of
batroxobin 10 BU within 24 h post-burn, the blood ﬁ brin-
ogen, plasminogen, ﬁ brin degradation D2-polymer and
anti-thrombin III, and other coagulation and ﬁ brinolytic
parameters were improved signiﬁ cantly compared with
the control group. Meanwhile, wound epithelialization
and healing time were signiﬁ cantly more advanced in the
treatment group with superﬁ cial second-degree burns.
Necrotic tissue was shedding earlier in patients with a
deep second-degree burn than in the control group.
Clinical application of batroxobin showed no relevant
complications and adverse reactions. It suggests that the
clinical use of batroxobin is safe and it can improve burn
hypercoagulability and promote wound healing.
Early Surgical Removal of Necrotic Tissue Wound
The pathophysiological process of burn wound healing is
different from other traumas (such as bruising) and the exis-
tence of necrotic tissue can cause damage to the wound.
The previous section mentioned that the presence of
necrotic tissue can lead to strong local inﬂ ammatory response
in deep second-degree burn wounds. Too strong an inﬂ am-
matory response not only causes progressive damage to
wound tissue, but also inhibits tissue repair. If removing the
necrosis as early as possible, the second injury caused by the
inﬂ ammatory response will be undermined. Tangential exci-
sion surgery is an effective way of removing necrotic tissue.
Since Janzekovic ﬁ rst proposed the surgery in 1968, the
method has been widely used in the treatment of deep
second- degree burn wounds. It has been shown that tangen-
tial excision for removing necrotic tissue can inhibit a local
inﬂ ammatory response that is too strong, prevent progressive
wound deepening, and at the same time increase the release
of local growth factors to promote wound healing. In addi-
tion, the tangential excision surgery itself can also promote
angiogenesis and play an active role in wound healing.
However, many studies have found that the progressive
deepening of deep second-degree burn wounds often occurs
within 48 h after the injury. The traditional surgical tangen-
tial excision tends to be performed 3–7 days after injury, and
at this time the inﬂ ammation has been over-activated, and
progressive injury has occurred in the wound stasis zone.
Thus, we wonder whether traditional surgical tangential
excision can effectively prevent deep second-degree burn
wounds from progressive deepening.
1. Experimental phenomena of very early tangential exci-
sion of burn wound to promote healing
Davis et al. [ 10 ] found that if the deep second wound
was tangentially excised within 24 h post-burn, the epithe-
lialization rate at 7 days post-burn was 75 %, while the rate
decreased to 22 % if tangential excision was done at 96 h
post-burn. Burn wounds that were excised 24 h after burn-
ing enhanced the rate of healing compared with those
excised after 96 h and nondebrided burn wounds. The dif-
ference between the healing time of skin burns and abra-
sions is that the former still needs to wait for the shedding
of necrotic tissue and then the subsequent healing speed is
same. The tangential excision within 24 h after burns can
advance the time to the start of the healing process, which
usually occurs at 3–4 days after injury. At the same time,
Davis et al. also believe that early surgical excision of the
wound can remove “necrosis toxins”, reducing progressive
injury in the zone stasis, thereby speeding up healing.
2. Histological evidence for the very early tangential exci-
sion of deep second-degree burn wound to prevent pro-
gressive deepening
A recent study [ 2 , 20 ] explored the very early tangen-
tial excision surgery of deep second-degree burn wounds
to prevent progressive deepening. Twelve patients with
deep second-degree burns underwent tangential excision
surgery at 24 h post-burn, and the wound tissue samples
obtained before surgery, after surgery or without surgery
were observed histologically by the method of HE stain-
ing, Masson’s staining, and immunohistochemical tech-
niques for marker vimentin antigen-positive cells. The
results showed that the extent of inﬂ ammatory response
in nonsurgical wounds was signiﬁ cantly increased, tissue
necrosis expanded, and the remnant skin appendages dis-
appeared (Tables 9.23 and 9.24 ). Masson’s red dye was
Table 9.22 Effect of batroxobin on ﬁ brinogen (Fg) levels in rats with deep second-degree scalds (g/L)
Group
Time post-burn
2 h
24 h
72 h
Scalded controls
0.17 ± 0.13* ( n = 4)
2.98 ± 0.39* ( n = 6)
2.34 ± 0.43* ( n = 6)
Batroxobin
1.25 ± 0.53 ## ( n = 8)
1.63 ± 0.39 # ( n = 3)
Normal controls
1.33 ± 0.25 ( n = 7)
Quoted from Fang Pei-yao et al. [ 21 ]
Compared with the normal control group, * p < 0.001
Compared with the scald control group, # p < 0.05; ## p < 0.001
9.1 Characteristics of Burn-Wound Healing

222
increased gradually, while the bright green part was grad-
ually reduced and the expression of vimentin antigen on
cells in the wound gradually decreased. The results
reﬂ ected aggravated damage. With a very early tangential
excision, wound local inﬂ ammatory response was signiﬁ -
cantly reduced compared with the nontangential wound,
and there was no further expansion of tissue necrosis. On
the contrary, we were able to see the formation of fresh
wound tissue granuloma (Table 9.25 ), signiﬁ cantly differ-
ent compared with the nonsurgical group ( p < 0.05). In
addition, Masson’s stain bright green areas showed no
signiﬁ cant narrowing, and the number of vimentin
antigen- positive cells was signiﬁ cantly higher than in the
nonoperated group. The results suggest that a very early
tangential excision, which is carried out by the timely
removal of necrotic tissue, can block the damage to tis-
sue, prevent progressive wound deepening, and promote
wound healing.
3. Effects of very early tangential excision of deep second- degree
burn wounds on the local release of growth factor [ 2 , 20 ]
Wound healing is a complex and dynamic process of
restoring cellular structures and tissue layers. Growth fac-
tor plays an important role in the repair process, and the
synthesis and secretion of growth factors are extremely
complex and subject to a variety of regulatory mechanisms.
Wound repair begins with the immediate response to the
injury, that is, the inﬂ ammatory response. When tissue suf-
fers from injury, blood coagulation occurs ﬁ rst of all, and
then the wound-healing process was initiated with the
ﬁ brous protein, ﬁ brin cleavage products, and platelet acti-
vation. Moderate inﬂ ammatory response is necessary for
wound healing and inﬂ ammation, while excessive or inad-
equate response will lead to wound healing “out of con-
trol.” There is already evidence that the persistence of the
wound of necrotic tissue can cause too strong a local
inﬂ ammatory response, inhibiting local growth factor syn-
thesis and secretion, leading to progressive wound deepen-
ing and wound healing delay. Removing the wound using
tangential excision of necrotic tissue can prevent progres-
sive wound deepening and promote wound healing. A
recent study revealed that a very early tangential excision
of deep second-degree burn wounds could promote the
local secretion of various growth factors to promote wound
healing. Twelve patients with deep second-degree burn
injuries underwent tangential excision within 24 h after
surgery, and the wound tissue samples were collected
before operation, after operation, and at the nonsurgical
wound. The release of EGF, FGF-2, PDGF-AB, and
VEGF levels of the samples, which were cultured in vitro,
was detected and at the same time samples underwent
Table 9.23 Batroxobin on FDP levels in the blood of rats with deep second-degree scalds (1 g μg/ml)
Group
Time post-burn
2 h
24 h
72 h
Scalded controls
2.10 ± 0.62 ( n = 4)
2.00 ± 0.65 ( n = 6)
1.45 ± 1.05*( n = 6)
Batroxobin
–
2.37 ± 0.41 ( n = 8)
2.10 ± 0.54 ( n = 4)
Normal controls
2.45 ± 0.40 ( n = 12)
–
–
From Fang Pei-yao et al. [ 21 ]
Compared with the normal control group, * p < 0.01
Table 9.24 Batroxobin on FDP levels in the wound in rats with deep second-degree scalds (1 g μg/ml)
Group
Time post-burn
2 h
24 h
72 h
Scalded controls
2.35 ± 0.17** ( n = 4)
1.70 ± 0.15 ( n = 6)
0.60 ± 0.49** ( n = 6)
Batroxobin
1.99 ± 0.36* ( n = 8)
2.71 ± 0.00 # ( n = 3)
Normal controls
1.52 ± 0.15 ( n = 7)
Quoted from Fang Pei-yao et al. [ 21 ]
Compared with the normal control group, * p < 0.01, ** p < 0.001, and scald control group, # p < 0.001
Table 9.25 Pathological observation of inﬂ ammatory inﬁ ltration in wound tissue before surgery, after surgery, and in the no surgery group
Group
Inﬂ ammatory inﬁ ltration ( n = 10)
−
+
++
+++
Pre-surgery
5
3
1
1
Nonsurgery
2
1
3
4
Post-surgery
3
5
1
4
+ indicates the degree of tissue inﬂ ammatory inﬁ ltration [ 3 ]
9 Burn Wound Healing

223
histological observation. The study found that the release
of EGF, FGF-2, PDGF-AB, and VEGF levels with a tan-
gential excision was signiﬁ cantly higher than those with-
out surgery (Table 9.28 ). Local histological observation
showed that the formation of postoperative wound granu-
lation was remarkably fresher than in the nonsurgical
wound. Many studies have shown that EGF is a growth
factor that plays an important role in the regulation of cell
growth, proliferation, and differentiation by binding to its
receptor EGFR. It can accelerate the epidermal keratino-
cyte cell migration, division, and proliferation, and it has
an effect on ﬁ broblasts and endothelial cells by promoting
the growth of granulation. As a strong angiogenic factor,
FGF-2 can stimulate vascular endothelial cell migration
and proliferation, thus mediating the formation of capillar-
ies. At the same time, FGF-2 stimulates secretion of plas-
minogen activator and collagenase, which can partially
degrade the ECM; thus, capillaries can extend to the
wound easily. FGF-2 has chemotaxis to ﬁ broblast cells
and promotes their proliferation, regulation of collagen
metabolism. FGF-2 can also promote epidermal cell mito-
sis; FGF-2 plays an important role in the formation of
granulation tissue. VEGF is another important angiogenic
growth factor, with the promotion of vascular endothelial
cell proliferation, migration, and differentiation role in the
wound healing process playing an important role in the
formation of new blood vessels. PDGF is a mitogen for a
variety of cells, such as ﬁ broblasts and endothelial cells.
PDGF as a correctional factor can function in the cell
cycle, which can make the cells from a static state G 0
phase enter the G 1 phase with a Copy “potential.” At the
same time PDGF can synergize EGF and TGF-ß to make
the cells across the restriction point from G 1 phase enter
the S phase, and thus contribute to the proliferation of
ﬁ broblast cells to form the required ECM to stimulate
granulation tissue formation, thereby promoting wound
healing. Clearly, there are inextricable links between the
increase in the secretion of a variety of growth factors and
more remarkable fresh granulation tissue formation by
histological observations after the very early tangential
excision. Thus, the very early tangential excision of deep
second-degree burn wounds can promote wound healing.
The mechanism of a very early tangential excision stimu-
lating high levels of wound growth factor release is not yet
clear. Is surgery itself a direct stimulation? Can surgery
with removal of the necrotic tissue restore the inhibition of
growth factor release? Or both? This needs to be explored
further.
4. Safety and effectiveness of clinical research of a very
early tangential excision
The clinical safety of very early tangential excision and
the validity of the surgery shortening the course of wound
healing have recently been conﬁ rmed in a study. Twelve
patients with surgical indications for deep II degree burn
injury underwent tangential excision within 24 h after
burns, and 14 patients with similar conditions of deep
Table 9.26 Pathological observation of necrotic tissue in wound tissue before surgery, after surgery, and in the no surgery group
Group
Necrosis ( n = 12)
−
+
++
+++
Pre-surgery
2
3
1
6
Nonsurgery
2
2
0
8
Post-surgery
5
4
3
0
+ indicates the extent of tissue necrosis [ 3 ]
Table 9.27 Pathological observation of granulation tissue in wound tissue before surgery, after surgery, and in the no surgery group
Group
Granulation ( n = 10)
−
+
++
+++
Pre-surgery
10
0
0
0
Nonsurgery
8
2
0
0
Post-surgery
4
3
3
0
+ indicates the extent of the formation of new granulation [ 3 ]
Table 9.28 Comparison of the level of growth factor with or without a very early tangential excision pg ml x
s
/
,
±
(
)
Group ( n = 12)
EGF
FGF-2
PDGF-AB
VEGF
Nonsurgery
31.9 ± 20.6*
14.35 ± 1.52*
31.75 ± 19.47*
9.57 ± 5.37*
Post-surgery
61.0 ± 30.1
21.32 ± 1.27
44.45 ± 20.59
12.28 ± 5.88
Compared with post-surgery, * p < 0.05 [ 3 ]
9.1 Characteristics of Burn-Wound Healing

224
second-degree burns according to clinical protocols were
selected for tangential excision surgery at 4–6 days after
injury as a contrast. The general situations of the two
groups are compared in Table 9.29 . The results showed
that there were no complications induced by early surgery
with the timing of surgery advanced to within 24 h after
burn, and no signiﬁ cant difference in infusion volume and
the occurrence and signs of shock compared with the con-
trol group at its shock stage (Tables 9.30 and 9.31 ), sug-
gesting the safety of early surgery. The patients with early
surgery had higher urine output during the shock period
compared with the control group (Table 9.32 ), which may
be related to the early removal of necrotic tissue, the exu-
date gap was reduced, and the swelling subsided in
advance. In addition, the study found that patients with
early tangential excision had a stable body temperature
and heart rate compared with the controls (Table 9.33 ),
reﬂ ecting the safety of early surgery from another
viewpoint.
The study found that the average healing time is
19.08 ± 5.31 days in the experimental group,, while the
control group was 29.36 ± 7.03 day, and there is a very
signiﬁ cant difference ( p < 0.01), suggesting that very early
tangential excision surgery might accelerate the wound
Table 9.29 General data of burns patients with the very early tangential excision group (A group) and the traditional tangential excision group
(B group)
Group sample
Age
TBSA (%)
First tangential excision
Post-burn (h)
Tangential area (%)
A
12
34.83 ± 10.64
23.58 ± 5.82
17.54 ± 5.20
18.75 ± 3.91
B
14
34.71 ± 8.65
23.14 ± 5.07
121 ± 41.67
14.92 ± 5.49
Table 9.30 Comparison of the intravenous ﬂ uid infusion (ml) with tangential excision at the shock stage group (group A) and the traditional
tangential excision group (group B)
Group
D1
D2
D3
Plasma
Ringer’s
Plasma
Ringer’s
Plasma
A
1,038.91 ± 763.39
1,391.67 ± 640.61
640 ± 231.90
825 ± 334.37
425 ± 138.87
( n = 11)
( n = 12)
( n = 10)
( n = 10)
( n = 8)
B
914.29 ± 310.97
1,403.57 ± 691.83
561.54 ± 225.60
634.62 ± 223.03
450 ± 167.87
( n = 14)
( n = 14)
( n = 13)
( n = 13)
( n = 12)
Table 9.31 Comparison of urine output (ml) in the tangential surgery group (group A) during the shock period and in the conventional tangential
excision group (group B)
Group
D 1
D 2
D 3
A
5,142.42 ± 2,931.53
3,937.67 ± 1,528.55
3,142.27 ± 957.12
( n = 7)
( n = 12)
( n = 11)
B
2,347.14 ± 739.16*
2,708.26 ± 887.28
1,678.57 ± 319.08**
( n = 7)
( n = 7)
( n = 14)
* p < 0.05; ** p < 0.01
Table 9.32 Signs of early diagnosis of burn shock in the tangential excision during the shock period group (group A) and the traditional tangential
excision group (group B)
Group A ( n = 12)
Group B ( n = 14)
Positive
Negative
Group A
Group B
Dorsalis pedis artery pulse beat weak
1
11
2
12
Tachycardia (>120 bpm)
1
12
2
12
Bad peripheral circulation
1
11
1
11
Obviously thirsty
0
12
1
13
Nausea and vomiting
0
12
0
14
Apathetic
0
12
0
14
Oliguria(<30 ml/h)
1
11
2
12
Rapid breathing
1
11
0
14
9 Burn Wound Healing

225
healing process. Regarding the timing of tangential exci-
sion surgery, the experimental group underwent the pro-
cedure 3–5 days earlier than the control group. With
regard to the average wound healing time, the experimen-
tal group was an average of 10 days ahead of the control
group, which suggests that the reason for very early tan-
gential excision reducing the number of days of wound
healing might not simply be because of the operation time
being put forward, but also its internal mechanism for
promoting healing. From the above, we conclude that
very early tangential excision can promote localized
release of EGF, bFGF, PDGF, VEGF, and other growth
factors, and it may block wound deepening and prevent
necrotic tissue expansion, so that the wounds healed
faster. According to this viewpoint, tangential excision
surgery for deep second-degree burn wounds within 24 h
after injury is not only safe but can also promote wound
healing.
Very early tangential excision surgery in the treatment
of deep second-degree burn wounds is important because
it not only changed the deep second-degree burn wounds
healing model, effectively preventing progressive deepen-
ing of the wound, but also by early removal of necrotic
tissue, it can improve the systemic inﬂ ammatory reaction,
which is the topical treatment of deep second-degree burn
wounds and systemic inﬂ ammatory response syndrome.
The current medical monitoring technology provides a
guarantee for the safety of very early surgery, which has
good prospects.
Hyperbaric Oxygen Therapy [ 22 ]
The mechanism of the progressive deepening of wound tis-
sue is related to local edema, the prothrombotic state, and
factors such as too strong an inﬂ ammatory response, which
causes hypoxia and ischemia in the wound tissue. Thus,
improving local tissue hypoxia is expected to prevent the
occurrence of progressive wound deepening.
It is well known that hyperbaric oxygen (HBO) can make
arterial oxygen reaching 200 kPa, even in the absence of
hemoglobin; the inhalation of HBO can still provide tissue
with enough oxygen to maintain the vitality of the tissue.
The maintenance of tissue oxygen tension depends on the
local blood ﬂ ow velocity, capillary density, cell metabolic
rate, pH value, and the arterial oxygen content. Under normal
pressure, 100 % oxygen inhalation can improve the oxygen
content in percent 2vol; thus, only HBO can increase tissue
oxygen levels.
The mechanisms of HBO in preventing wound deepening
and promoting wound healing may be as follows:
1. HBO can cause vasoconstriction, reducing blood ﬂ ow by
about 20 %, while the oxygen content is increased by ten
times. Leakage of blood cells, bleeding, and edema in the
local wound were also reduced. In the ischemic state and
wound progressive deepening process, the edema reduc-
tion can not only improve blood ﬂ ow and capillary perfu-
sion but can also maintain aerobic metabolism, which
plays an important role in maintaining the integrity of the
capillaries.
2. Fibroblast proliferation, collagen matrix formation, and
new capillary formation are dependent on a certain degree
of tissue oxygen tension in the absence of a blood supply
in the wound. The oxygen tension is generally between
0.66 and 2 kPa, and this tension level may be sufﬁ cient to
maintain the vitality of the organism, but is not an effec-
tive synthesis of collagen and other substances. Therefore,
HBO plays an important role in the promotion of ﬁ bro-
blast proliferation, angiogenesis, and collagen production
by increasing oxygen tension in the tissue.
Reducing local edema, preserving the living tissue at the
edge of the wound, and promoting wound healing is an
important principle of the treatment of burn wounds. In many
animal studies it was found that HBO can reduce local
wound edema, reduce leakage, and improve the blood con-
centration and microcirculation to maintain the integrity of
blood vessels. At the same time, it also can retain the dermis
to improve the quality of collagen and shorten healing time.
In addition, HBO can maintain the level of ATP in the tissue
near the second-degree burn wounds to be a substrate provid-
ing energy to maintain the living tissue, which may be the
reason to prevent progressive wound deepening. Another
experiment further conﬁ rmed that the HBO therapy could
reduce the peripheral blood neutrophil inﬁ ltration to the tis-
sue and the production of oxygen free radicals, thereby pre-
venting progressive wound deepening.
The clinical application of HBO for burns began in 1965,
and for many years of clinical practice, HBO treatment of burn
wounds has been recognized as an aid for clinicians. Clinical
studies suggest that HBO might reduce the amount of ﬂ uid
Table 9.33 Comparison of body temperature (T) and heart rate (HR) between tangential excision at the shock stage group (group A) and the
traditional tangential excision group (group B) during the period of burn ﬂ uid re-absorption
Group samples
D 3
D 4
D 5
T
HR
T
HR
T
HR
A
12
38.1 ± 0.62
101.5 ± 12.77
37.9 ± 0.68
97.83 ± 15.57
37.74 ± 0.67
95.17 ± 15.46
B
14
38.55 ± 0.64
114.43 ± 12.73*
38.34 ± 0.44
108.36 ± 12.10
38.5 ± 0.41**
108 ± 8.45*
* p < 0.05; ** p < 0.01
9.1 Characteristics of Burn-Wound Healing

226
infusion in the shock period, to reduce wound edema and exu-
dation and promote wound healing. For deep second- degree
burn wounds in particular it can signiﬁ cantly shorten the heal-
ing time. In addition, use of HBO can reduce the number of
days in intensive care and hospitalization, save medical costs,
and reduce mortality. Some scholars believe that HBO should
only be considered as an additional means of treating wounds,
so that wounds in the hands, ﬁ ngers, face, neck, ears, perineum,
and other locations in which it is difﬁ cult carry out surgery and
coverage are treated. The timing of HBO treatment should be
started during the early stages after a burn, three times in the
ﬁ rst 24-h, and then twice a day, the pressure was chosen to be
2ATA, time 90 min, including step-up and step-down time. In
children the dosage is twice daily, for 45 min each time. It
needs intensive care, accurate calculation of the amount of
rehydration, and strictly controls the infusion rate during treat-
ment. Patients with fever, who are prone to oxygen toxicity,
need intensive care. Patients with inhalation injury are not
suitable for treatment with HBO, because HBO can increase
lung injury. HBO therapy is generally safe, although the clini-
cal study of HBO in promoting burn wound healing is limited,
but to promote the healing of burn wounds an additional means
should be explored further.
Anti-Oxidant Therapy
Xanthine oxidase was activated in a hypoxic state and oxygen
free radicals were produced after local inﬁ ltration of neutro-
phils, both of which are the direct participants leading to tissue
damage. Therefore, researchers are concerned about how to use
anti-oxidants to prevent wound tissue damage. Early studies
have shown that superoxide dismutase (SOD) and catalase
(CAT) in vitro had a good anti-oxidant effect, but in vivo it did
not have a satisfactory effect, because of its short half-life, high
molecular weight, and poor penetration. The studies indicate
that the degree to which oxygen free radical activity in burns
patients increased is closely related to the degree of vitamin E
decline. These oxygen free radicals can damage the red cell
membrane, so that the cell deformation was reduced and easily
able to accumulate in the blood vessels to affect the blood ﬂ ow.
Vitamin E given at an earlier stage after burns can restore red
blood cell function and improve microcirculation, because it has
the ability to resist oxygen free radicals. Vitamin C is also an
important anti-oxidant. The animal experimental study found
that high doses of vitamin C treatment could reduce local wound
edema and lipid peroxidation. The clinical efﬁ cacy and mecha-
nism of vitamin E and vitamin C for preventing burn wound
progressive deepening is yet to be further explored, but it may
well be a way of improving the burn wound.
Others
Data show that the application of bradykinin receptor antag-
onist NPC17731, C1 inhibitor, creatinine triphosphate (IP3),
PGI2, and its analog beraprost sodium can reduce local
edema in the burn wound. Studies also conﬁ rmed that the
application of a soluble sCR1 to close C3a and C5a can
reduce complement activation and neutrophil-mediated tis-
sue damage effects.
In burn wound tissue, the necrotic tissue, ischemia and
hypoxia, inﬂ ammatory mediators and cytokines can activate
endothelial cells and neutrophils, activating endothelial cells
to express adhesion molecules ELAMs and ICAM-1, and
activating the neutrophils surface, the expression of selectin
LECAM-1, and the integrin CD11b/CD18, then dependent
on a combination of these surface molecules. Neutrophils
were activated to local tissue inﬁ ltration. The experiments
conﬁ rmed that the application of CD18, CD11b/CD18, and
ICAM-1 monoclonal antibody can block neutrophil adhe-
sion and extravasation, signiﬁ cantly reduce local edema,
increase blood ﬂ ow to the wound tissue, and reduce neutro-
phils inﬁ ltration, thus mitigating wound damage.
Some people have even envisioned through neutrophil
apoptosis being eventually engulfed by macrophages as a
way of blocking inﬂ ammation and further damage occurring.
However, the above description of the methods states that
they are more expensive, the have side effects, safety and
other issues have not yet reached the standard of medicine,
and clinical application is far from a considerable distance.
9.1.4
Contemporary Concepts of Burn
Wound Healing [ 2 , 3 , 23 ]
Wound healing is a complex yet orderly process that includes
inﬂ ammatory responses, cell proliferation/connective tissue
formation, and wound contraction as well as remodeling. These
stages are not independent, but intersect and overlap with one
another. The process involves various inﬂ ammatory cells,
repair cells, inﬂ ammatory mediators, growth factors, and ECM
components. Wound healing is a coordinated and regulated
process characterized by orderliness, integrity, and network.
The initial stage of wound healing is the inﬂ ammatory
response. At this stage, platelets aggregate and secrete the
pro-coagulant factors, chemotactic factors, and growth fac-
tors. Neutrophils, macrophages, and lymphocytes are
recruited successively into the wound bed. These factors and
cells play different roles in wound healing. Although neutro-
phils contribute to the release of inﬂ ammatory mediators and
the clearance of necrotic tissue, studies have found that
wound healing is not impaired in animals with decreased
neutrophils, suggesting that neutrophils might not be directly
involved in cell proliferation and wound healing. Recent evi-
dence indicates that proinﬂ ammatory cytokines produced by
neutrophils may serve as the earliest signal to activate ﬁ bro-
blasts and keratinocytes. The role of neutrophils in wound
healing should be studied further. It is well known that mac-
rophages play an important role in wound healing, and some
9 Burn Wound Healing

227
researchers think of them as regulatory cells. Wounds cannot
heal without the involvement of macrophages. Inﬁ ltrating
macrophages function not only to clear necrotic tissue, bac-
teria, and foreign bodies but also to secrete growth factors
such as PDGF, EGF, transforming growth factor (TGF)-α
and -β, interleukin (IL)-1, heparin-binding EGF, macrophage-
derived growth factor (MDGF), and WAF. These cytokines
are chemotactic and can also stimulate mitosis of ﬁ broblasts
and promote neovascularization and the formation of granu-
lation tissue, which are indispensable in wound repair. In
addition, macrophages have dual effects on collagen: stimu-
lating its production and promoting its degradation. This
suggests that macrophages exert dual control in the prolifera-
tion stage of wound healing, preventing undue proliferation.
It also suggests that, apart from their roles in the inﬂ amma-
tory and proliferation stages of wound healing, macrophages
participate in the wound remodeling process. Studies have
also demonstrated the presence of macrophages in the late
stage of wound healing and in healed wounds, suggesting
macrophage modulation throughout the whole wound heal-
ing process. Lymphocytes appear late in the inﬂ ammatory
stage of wound healing. There is no evidence to support a
direct role of lymphocytes in wound healing. However, cyto-
kines secreted by lymphocytes are critical for wound heal-
ing. Delayed wound healing and decreased production of
collagen have been found in an animal model of immuno-
suppression established by low-dose cobalt-60 exposure.
Lymphocytes inﬂ uence wound healing via the production of
cytokines that inhibit or activate ﬁ broblasts in the process of
wound healing.
Keratinocytes, ﬁ broblasts, and vascular endothelial cells
are also important participants in wound healing. The prolif-
eration of these cells leads to angiogenesis, matrix forma-
tion, and wound contraction, as well as re-epithelialization.
Angiogenesis results from the proliferation and migration of
vascular endothelial cells. Endothelial cells migrate from
intact blood vessels to damaged zones after release by col-
lagenase and other enzymes. Proliferated endothelial cells
form tubular structures and capillary sprouts that connect
with one another to form vascular nets. ECM deposits within
these vascular nets form the new basement membrane of
blood vessels. Inﬂ ammatory cells secrete growth factors and
collagenase, which initiate the migration of endothelial cells.
Growth factors such as aFGF, bFGF, TNF-β, EGF, and WAF
play important roles in the entire process of angiogenesis.
ECM is produced in the proliferative stage. However, this
production begins when macrophages migrate to the injured
area. Therefore, the proliferative stage may overlap, in part,
with the inﬂ ammatory stage. The number of inﬂ ammatory
cells in the wound decreases in the transition period from the
inﬂ ammatory stage to the proliferative stage. However, the
number of ﬁ broblasts increases at this stage. The prolifera-
tion of ﬁ broblasts promotes the expression of PDGF, TGF-β,
and other growth factors to regulate the synthesis and deposi-
tion of ECM, including ﬁ bronectin, laminin, glycosamino-
glycans, and collagens. The ECM not only simply ﬁ lls the
wound defect, but also regulates the functions of cells that
participate in the wound-healing process. Re-epithelialization
is critical for the covering and healing of wounds, which
involves the migration, proliferation, and differentiation of
keratinocytes. Keratinocytes, derived from wound margins
or residual hair follicles and sweat glands, migrate within
several hours after stimulation. Migrated keratinocytes pro-
liferate in the injured area to cover the wound, eventually
connecting with the basement membrane. Reconstruction of
the epithelium and the supportive basement membrane is
indispensable for the formation of an impermeable barrier.
The epithelial cells may slide across the defect in small
groups, or “leapfrog” across one another to cover the defect,
both of which preserve the tight junctions between epithelial
cells. The migration of these multiple layers of keratinocytes
continues until a basement membrane is formed in the
completely covered wound. Keratinocytes secrete cytoplas-
mic membrane-like substances, such as ﬁ bronectin, colla-
gen,
and
laminin.
Growth
factors
also
inﬂ uence
re- epithelialization. For example, EGF and TGF-β have been
shown to promote re-epithelialization; keratinocyte growth
factor (KGF; also known as FGF-7) secreted by macro-
phages enhances the proliferation of keratinocytes, and
bFGF and PDGF directly increase the production of new
connective tissue, leading to the promotion of re-
epithelialization. Residual keratinocytes along the wound
edge and in the wound bed are the source of these growth
factors. Tissue remodeling occurs at a late stage of wound
healing. Excessive collagen and matrix produced during
wound healing are degraded by collagenase and/or other
degradative enzymes. Then, inﬂ ammatory cells leave the
healed area gradually and a remodeled healed tissue results.
Inﬂ ammatory mediators, ECM, and growth factors are
essential for the chemotaxis, activation, proliferation, differ-
entiation, and migration of neutrophils, monocytes, macro-
phages, lymphocytes, keratinocytes, ﬁ broblasts, and vascular
endothelial cells. One of the salient features of wound heal-
ing is the cascade of complex biological events that occurs
immediately after injury. Early factors and mediators acti-
vate subsequent responses and regulate concurrent responses.
All of the stages of wound healing are regulated by growth
factors produced and secreted by cells involved in tissue
repair. A cell can secrete several factors and the same factor
can be produced by different cells. A factor acts on a speciﬁ c
cell or different cells, leading to different cellular responses,
and several factors or mediators can induce the same
response. Consequently, these factors and mediators work
with inﬂ ammatory and tissue repair cells to form a compli-
cated network for wound healing. Cellular proliferation and
suppression and the synthesis and degradation of the ECM
9.1 Characteristics of Burn-Wound Healing

228
are in equilibrium. Thus, burn wound healing is a multi-
phase process involving mediators, matrix, factors, and cells.
For example, speciﬁ c chemotactic factors, especially TGF-β
and PDGF, can induce the inﬁ ltration of macrophages, which
in turn are the main source of growth factors underlying the
inﬂ ammatory response. Platelet-derived growth factors and
other chemotactic factors produced by monocytes stimulate
the proliferation of adjacent ﬁ broblasts and their migration
to the injured area. This response is mutually regulated by
suppressive and activating factors. Migrating and proliferat-
ing ﬁ broblasts also process signals implicated in the transi-
tion period from inﬂ ammation to proliferation. In addition,
ﬁ broblasts also produce growth factors that are necessary for
wound remodeling. These factors promote the synthesis of
collagen and also enhance the activity of collagenase, thus
controlling the complicated process of synthesis and degra-
dation at the remodeling stage.
The mechanisms whereby growth factors exert their
effects and the signal transduction pathways involved have
been the focus of recent studies. These growth factors act on
remote cells in an endocrine manner, on adjacent cells in a
paracrine manner, and on themselves in an autocrine manner.
Via speciﬁ c signaling pathways, different growth factors can
induce different cellular responses and functional expres-
sion. These pathways have a common feature in that growth
factors combine with their speciﬁ c high-afﬁ nity receptors in
the cell membrane to activate signaling pathways. Most
growth factors combine with intracellular tyrosine kinases to
induce cellular responses (such as an increased release of
intracellular calcium). These responses are related to protein
phosphorylation, resulting in the phosphorylation of nuclear
proteins, which is necessary for the expression of target
genes. The entire process results in enhanced protein synthe-
sis and the alteration of cell viability and cell proliferation.
9.2
Exploration of the Mechanisms
of Impaired Burn Wound Healing
in Diabetic Patients
Shuliang Lu, Ting Xie, and Yiwen Niu
Cutaneous wound healing is a natural restorative response to
tissue injury via a sequence of pathophysiological processes
in the fashion of proliferation and regeneration and is
obtained as an ability for self-preservation and renovation in
the long biological evolutionary process. As with other activ-
ities of living, wound healing is a tightly controlled dynamic
process. Within a certain range, the systemic or local impact
on wound healing can be controlled. Once the pathological
changes exceed the body’s regulation capacity, impaired
wound healing will result [ 1 – 3 , 23 ].
Among the factors underlying dysregulated wound heal-
ing, impaired wound healing in diabetes mellitus merits sub-
stantial attention [ 24 , 25 ]. The increasing prevalence of
diabetes and limited intervention result in a poor prognosis
and heavy economic burden. For this reason, much work has
been performed to the problem of wound healing in diabetes,
especially diabetic foot ulcer.
Diabetic patients often present with impaired wound heal-
ing and recalcitrant foot ulcers [ 5 , 6 ]. The pathogenesis of
diabetic foot ulcers is considered to be the interactive pro-
cesses of angiopathy and neuropathy. Insufﬁ cient blood sup-
ply and infection are the causes of delayed wound healing
and ulcer development. Molecular analyses have identiﬁ ed
the following pathogenic markers that correlate with delayed
wound healing in diabetes mellitus:
1. Inhibition of macrophage migration contributes to the
deﬁ ciencies in neutrophils chemotaxis directly or indi-
rectly, although an increased number of inﬂ ammatory
cells was observed in the wound after injury [ 26 – 28 ].
2. Abnormal expression of growth factors involved in the
bioeffects of chemotaxis, synthesis and secretion, and pro-
liferation and differentiation of tissue repair proliferation
have been described in diabetic foot ulcers [ 29 – 41 ].
3. Diminished neuropeptide levels contribute to the impaired
healing response associated with cell activity and growth
factor synthesis in diabetes mellitus [ 42 – 44 ].
4. Disequilibrium between matrix metalloproteases (MMPs)
and their inhibitors (TIMPs) induces the impairment of
matrix deposition and reduction of neovascularization.
The abnormal expression of growth factors may be the
cause of this disequilibrium [ 45 – 50 ].
5. Various defective actions of cells [ 51 – 54 ], such as che-
motaxis and phagocytosis of inﬂ ammatory cells, prolif-
eration of ﬁ broblasts, response to growth factors, synthesis
of collagen, etc., have been identiﬁ ed in diabetic wounds.
6. Glycosylation products due to hyperglycemia lead to free
radical generation, resulting in oxidative stress [ 55 – 58 ].
7. Local high glucose content, excessive or insufﬁ cient
nitric oxide (NO), and abnormal expression of growth
factors are involved in the suppression of the regeneration
of residual capillaries in the wound bed [ 59 – 62 ].
The above-mentioned work outlines the general appearance
of the molecular events and pathophysiology of diabetic wound
healing to a certain degree, which promotes the exploration of
mechanisms underlying these refractory wounds. However, the
therapeutic strategies based on research have not proved satisfac-
tory. It is imperative to reconsider this issue. First, refractory
wounds in diabetic patients include spontaneous ulcers and trau-
matic wounds. Is there a difference in the mechanisms underly-
ing these refractory wounds? Second, peripheral neuropathy and
vascular diseases in diabetes mellitus form the pathological basis
of refractory wounds. However, they cannot completely explain
the cytology and molecular biology underlying diabetic
9 Burn Wound Healing

229
dermopathy. Why? Third, at present, therapeutic strategies aimed
at speciﬁ c events in the wound healing process have shown con-
tradictory outcomes in animal experiments and clinical trials, but
these outcomes are not correlated. Is there a common “switch”
contributing to the various abnormalities in the mechanisms
underlying diabetic wound healing?
Recent studies [ 63 – 70 ] have shown that vasculopathy in
lower-extremity diabetic ulcers is characterized by luminal
stenosis resulting from the thickening of the basement mem-
brane. Vascular repair is initiated by the migration of residual
capillary components to the ulcer. However, the insufﬁ cient
blood supply usually results in the disturbance of capillary
regeneration. In addition to the above process, neovasculariza-
tion induced by traumatic stimulation also plays an important
role in the healing of traumatic wounds. Other studies [ 71 ]
have found that some biological changes involving the expres-
sion of certain growth factors in spontaneous ulcers differ sig-
niﬁ cantly from those in traumatic wounds and that preexisting
biological changes in diabetic skin may be the main cause.
These biological changes induce the pathological process
characterized by vascular abnormalities and peripheral neu-
ropathy, leading to the development of spontaneous ulcers in
diabetes mellitus. Although the healing of developed ulcers
involves various elements of wound healing, it is a continuum
of the same pathological process. This differs in multiple
aspects from the wound-healing process of traumatic wounds
in diabetic patients. Research into the mechanisms underlying
dysregulated wound healing should therefore include refrac-
tory traumatic wounds and lower- extremity ulcers.
The wound beds of spontaneous ulcers and traumatic
wounds in diabetic patients share a common trait: refractori-
ness. Although vascular abnormalities and peripheral neu-
ropathy are the main causes of refractory wounds, they cannot
completely explain the biological abnormalities underlying
refractory wounds. Therapeutic interventions based on this
understanding have fared poorly in clinical trials and clinical
practice. Such a poor therapeutic outcome may be because
the vascular abnormalities and peripheral neuropathy are the
result of complications of diabetes. It is important to investi-
gate the characteristics of skin and wound healing in diabetic
patients and to ﬁ nd the common “switch” in the regulation of
different biological processes underlying wound healing that
may lead to the identiﬁ cation of initiators of delayed wound
healing, providing potential therapeutic targets.
9.2.1
Characteristics of Skin in Diabetes
Mellitus
Wound healing in diabetic patients progresses from intact
skin to injured skin to repaired skin. Determination of abnor-
mal histological, cytological, or molecular changes existing
before skin trauma is therefore of signiﬁ cance.
Diabetes is a metabolic disease characterized by hyper-
glycemia. The concentration of glucose was found to be two
to three times higher in the skin of diabetic rats than in that
of normal rats (2.64 ± 1.03 mg/g vs 0.74 ± 0.33 mg/g) and
correlated positively with the blood glucose level ( r = 0.58,
p < 0.01) [ 72 ]. As diabetes progresses, delayed wound heal-
ing becomes more noticeable. It has been shown that the con-
centration of glucose in the skin of diabetic rats with delayed
wound healing is signiﬁ cantly elevated compared with that
in rats with normal wound healing (14.24 ± 2.96 mmol/g vs
4.50 ± 0.47 mmol/g; p < 0.01). Accumulation of glycometa-
bolic products such as advanced glycation end products
(AGEs) was increased around the basement membrane, in
the dermal matrix, and in the cells of diabetic rats, and the
amount of AGEs progressively increases with the progres-
sion of diabetes [ 73 ] (Fig. 9.1 ). This implies that the delay
in wound healing is associated with altered metabolism in
diabetic patients. The locally enhanced concentration of glu-
cose and deposition of AGEs are important features of the
biochemical environment in diabetic skin.
Cutaneous histological observation showed reduced
thicknesses of the epidermis and dermis in diabetic skin with
morphological characteristics of obscured multilayer epithe-
lium, atrophied collagen ﬁ bers, and focal chronic inﬂ amma-
tory cell inﬁ ltration [ 73 , 74 ] (Fig. 9.2 ). The content and
physicochemical properties of collagen are also abnormal.
The content of hydroxyproline and the solubility of collagen
are markedly decreased [ 73 ].
Repair cells, including keratinocytes, ﬁ broblasts, and vas-
cular endothelial cells, play a critical role in maintaining the
metabolic balance in the skin and in wound healing via prolif-
eration, apoptosis, secretion, and other functions [ 75 ]. By
TUNEL assay, positive immunostaining for apoptosis cells
was found in diabetic skin tissue, whereas it was rarely
expressed in controls. Results for apoptotic-related proteins
showed that Bcl-2 expression in diabetic skin was reduced
(2.140 ± 0.545 pg/g vs 3.067 ± 0.711 pg/g; p < 0.05), but no dif-
ference in Bax expression was observed compared with that in
nondiabetic skin. The expression of p53 was signiﬁ cantly
elevated (6.153 ± 1.004 pg/g vs 4.496 ± 1.271 pg/g; p < 0.05)
[ 76 ]. In diabetic rats, the viability and adhesion ability of kera-
tinocytes from skin tissue were decreased; the percentage of
apoptotic keratinocytes was increased (7.57 % ± 0.55 % vs
4.57 % ± 0.37 %; p < 0.05), and the proliferative ability of
keratinocytes was suppressed, with delayed entrance into the
cell cycle [ 77 , 78 ]. Downregulated expression of cdk4 and
Ki67 and decreased activity of maturation promoting factor
(MPF) contributed to keratinocyte proliferation disorder [ 78 ].
Growth factors are important mediators secreted by a
variety of cells. On binding to their corresponding receptors,
growth factors promote the proliferation and chemotaxis
of cells, increase protein synthesis, maintain metabolism
in the skin, and regulate wound repair. Increasing evidence
9.2 Exploration of the Mechanisms of Impaired Burn Wound Healing in Diabetic Patients

230
indicates abnormal expression of growth factors in the skin
of patients with diabetics. Generally, growth factors, which
promote wound healing, are downregulated in diabetic
skin tissue. However, some studies have shown contradic-
tory results. In a diabetic rat model, the content of EGF
per unit area was signiﬁ cantly increased in the epidermis
compared with that in control rats (39.26 ± 0.44 pg/cm 2 vs
37.57 ± 0.71 pg/cm 2 ; p < 0.05). The expression of FGF-2 was
not decreased, whereas that of its receptor (FGFR) was dra-
matically increased [ 79 , 80 ]. Double-labeling immunoﬂ uo-
rescence indicated the colocalization of FGF-2 and AGEs
(Fig. 9.3 ) [ 73 ]. These results suggest that the number of
growth factors with normal activity might be signiﬁ cantly
downregulated in diabetic skin.
Inﬂ ammatory cells exert their inﬂ uence by migrating to
the wound margins after injury. Inﬁ ltration of inﬂ ammatory
cells is observed in areas with collagen denaturation in the
intact skin of patients with diabetes. The elevated content of
MPO implies increased numbers of neutrophils. An increased
MDA level directly suggests enhanced oxidative membrane
damage in diabetic skin. Vimentin expression and a higher
ratio of aMMP-2 to TIMP-2 are also observed. These results
thus demonstrate the presence of excessive inﬂ ammatory
cells and tissue injury in diabetic skin [ 73 ].
The aforementioned characteristics of diabetic skin sug-
gest that abnormal histological and cellular changes exist
before traumatic skin injury. These characteristics involve
various steps of the wound healing process and also indicate
a
b
Fig. 9.1 Immunohistochemical localization of advanced glycation end
product (AGE) proteins in the dermis is shown. The distribution of AGE
in ( a ) normal skin tissue and in ( b ) diabetic skin tissue, AGE protein
staining was expressed faintly at the dermal matrices and cells in control
skin, but was prominent at the dermal matrices, cells, and basement
membrane of vessels in the diabetic skin (Original magniﬁ cation ×400)
a
b
Fig. 9.2 Histological appearance of skin tissue with hematoxylin and eosin staining is shown. ( a) Control skin tissue; ( b ) diabetic skin tissue
(Original magniﬁ cation ×400)

9 Burn Wound Healing

231
the different basis for injury from normal skin, which affects
the process of wound healing. Of note, cells, ECM, and
growth factors are involved in the pathophysiological and
molecular changes. These alterations have their own features
but interact with one another. It is reasonable to postulate
that these abnormalities might have common initial events.
9.2.2
Characteristics of Burn Wound Healing
in Patients with Diabetes
Deep second-degree burns involve the dermis under the pap-
illary layer, and residual dermis may be preserved. Hair fol-
licles and sweat glands in the reticular layers of the dermis
that promote wound healing via regeneration are generally
preserved. However, before the wound is covered by prolif-
erative epithelial cells, granulation tissue appears. The path-
ological changes in deep second-degree burn wounds make
them a good model for the exploration of mechanisms under-
lying refractory wounds in diabetes.
In diabetic rats with deep second-degree burns, features
typical of refractory wounds, such as delayed exfoliation of
necrotic tissues, aggravated infection, poor granulation, and
delayed re-epithelialization are observed [ 81 ].
Fibroblasts are one of the main types of repair cells.
Mature ﬁ broblasts secrete ECM, including collagen and
ﬁ bronectin, which ﬁ ll defective areas and provide support for
keratinocytes. In addition, activated ﬁ broblasts are involved
in the regulation of wound healing via the secretion of growth
factors such as TGF-β and FGF. However, the numbers of
ﬁ broblasts in wounds of diabetic patients are dramatically
decreased, and a decrease in collagen deposition is observed.
Electron microscopic results have shown swollen mitochon-
dria or vacuolar degeneration and dilatation of rough endo-
plasmic reticulum in ﬁ broblasts derived from wounds of
diabetic rats. Scattered ribosomes and chromatin margin-
ation and cavitation, features typical of apoptosis, were also
observed. Accumulation of senescent ﬁ broblasts were also
found around these apoptotic cells [ 82 – 84 ].
The initiation and development of inﬂ ammation are
closely related to vascular endothelial cells, whose activa-
tion, migration, chemotaxis, proliferation, and differentia-
tion are critical for neovascularization. The growth factors,
ECM molecules, and proteases produced by these vascular
endothelial cells are also involved in the regulation of wound
healing. In a diabetic rat model, the number of vascular
endothelial cells in newly generated matrix was not
decreased, and the functions of these cells were normal, with
a tendency toward proliferation [ 85 , 86 ]. However, other
studies showed that the vascular endothelial cell function
was decreased and electron microscopic analysis revealed
degenerated vascular endothelial cells, vacuolar degeneration
a
b
c
d
e
f
Fig. 9.3 Immunoﬂ uorescence detection of ﬁ broblast growth factor
(FGF)-2 and AGE in ( b , d , f ) normal and ( a , c , e ) diabetic skin is shown
here. The micrographs depict the following: ( a ) the expression of
FGF-2 in diabetic skin; ( b ) the expression of FGF-2 in normal skin;
( c ) the expression of AGEs in diabetic skin; ( d ) the expression of AGEs
in normal skin; ( e ) doubled-labeled immunoﬂ uorescence of FGF-2 and
AGE in diabetic skin; and ( f ) double-labeled immunoﬂ uorescence of
FGF-2 and AGE in normal skin (Original magniﬁ cation ×200)

9.2 Exploration of the Mechanisms of Impaired Burn Wound Healing in Diabetic Patients

232
in the cytoplasm, reduced number of organelles, cell swell-
ing, chromatin condensation, and thickened basement mem-
brane in diabetic wounds [ 87 ]. Regardless of whether cell
proliferation was suppressed, the density of newly generated
functioning vessels was reduced (Fig. 9.4 ). Some studies
have indicated that during normal traumatic wound healing,
the wound signal stimulates local secretion of angiopoietin- 2
(Ang-2) and VEGF, which promote the migration of residual
vascular endothelial cells as capillary sprouts [ 88 ]. Then,
with Ang-2 subsiding, tube formation and the maturation of
blood vessels are induced by Ang-1. However, a persistent
upregulation of Ang-2 is found in diabetic rats with burn
wounds. These results imply impaired neovascularization in
wound repair in diabetic rats, characterized by a reduced
number of newly generated functioning vessels. The sup-
pressed proliferation of vascular endothelial cells may not be
the only cause of dysfunction of vascular remodeling; the
improper construction of these newly generated vessels may
also be involved.
Successful wound healing requires re-epithelialization
over the wound area. Keratinocyte proliferation is consid-
ered a major event during re-epithelialization, which contrib-
utes to the healing process and quality. Profoundly delayed
epithelialization has been observed at every time point after
injury in diabetic rats. In the diabetic group, the keratino-
cytes adjacent to the wound margin were observed to have a
proliferating tendency since the early stages post-burn, but
presented disorder or deﬁ cient multilayer epidermis and
fewer cells. Re-epithelialization was delayed at 14 days after
injury, and keratinocytes were arrested in the S phase. The
expression of cyclin D1 and cdk4 and the activity of MPF
were signiﬁ cantly decreased, resulting in impaired mitosis.
These results indicate that the decreased expression and
activity of cell-cycle regulators are involved in delayed re-
epithelialization and delayed wound healing in diabetes mel-
litus [ 89 ].
During wound healing, the expression of some growth
factors is impaired to a certain extent. Among these, VEGF
and FGF-2 are the main regulators of vascularization that
stimulate the proliferation, migration, and adhesion of vascu-
lar endothelial cells, resulting in neovascularization. These
growth factors also induce the secretion of collagenase, lead-
ing to the degradation of ECM, which facilitates the exten-
sion of capillaries into the wound bed. Studies in diabetic
rats with deep second-degree burn wounds indicate that the
level of VEGF is signiﬁ cantly increased, whereas that of
FGF-2 is no less than in normal rats [ 79 , 80 , 90 ]. The colo-
calization of FGF-2 and glycated proteins was demonstrated
by immunoﬂ uorescence analysis in diabetic wounds. Thus,
the expression of growth factors is not deﬁ nitively upregu-
lated or downregulated in wounds of patients with diabetes.
Mechanisms underlying wound refractoriness include not
only changes in the quantity of growth factors but also the
glycation of growth factors, which may lead to a deﬁ ciency
in biologically active growth factors. The topical application
of exogenous FGF-2 increases the generation of new colla-
gen, improving the repair functions of cells and elevating the
expression of FGF-2 mRNA, conﬁ rms this hypothesis [ 91 ].
The inﬂ ammatory response is an important event in
wound healing. In normal skin, inﬂ ammatory cells exert
their inﬂ uence on the wound by migrating to the wound mar-
gin in response to chemotactic factors. This process results in
the formation of a clear inﬂ ammatory belt. However, inﬂ am-
matory cells in the wounds of diabetic patients constitute dif-
fused inﬁ ltration and can be observed persistently during the
entire process of wound healing. Furthermore, the content of
a
b
Fig. 9.4 Comparison of wound vascularity of the diabetic and the control group on seventh post-burn day. ( a) Control skin tissue; ( b) diabetic skin
tissue (Original magniﬁ cation ×400)

9 Burn Wound Healing

233
MDA and MPO is also increased continuously, with a
dynamic disequilibrium between MMP2 and TIMP2, sug-
gesting an active inﬂ ammatory response and ongoing dam-
age to the wound bed by free radicals [ 92 ]. These results
suggest the presence of an abnormal inﬂ ammatory response
during the entire process of wound healing in diabetes
mellitus.
Preliminary exploration of the characteristics of diabetic
skin and wound healing in diabetic mellitus has revealed the
mechanisms underlying refractory wound healing. These
include abnormalities of cellular functions, ECM, and
growth factors and their interactions, resulting in a compli-
cated network of dysregulated wound healing. It is notewor-
thy that regardless of whether it is in intact skin tissue or
during wound healing, a high concentration of glucose and
the accumulation of AGEs and glycation effects are consis-
tently observed in diabetic skin. Thus, the question what role
the products of glycometabolic disorders play in diabetic
wound healing is put forward.
9.2.3
The Relation Between Glycometabolism
and Healing-Related Factors in Wounds
of Diabetes Mellitus
Diabetes mellitus is a disorder characterized by hyperglyce-
mia owing to an absolute or relative deﬁ ciency of insulin and
or insulin resistance. Persistent pathological hyperglycemia
activates the polyol pathway, diglyceride–protein kinase C
pathway (DAG-PKC), and nonenzymatic glycation, result-
ing in disturbance of the internal milieu. Thus, the pathologi-
cal changes in functions and structures of cells, tissues, and
organs in diabetes play an important role in the occurrence
and development of diabetic complications. Nonenzymatic
glycosylation, which results from persistent hyperglycemia,
is one of the activities of metabolic remodeling, leading to
high local glucose content and to the accumulation of AGEs,
which have multiple biological activities, leading to the dys-
function of cells and tissues directly or via corresponding
receptors. Studies have conﬁ rmed that AGEs are involved in
the occurrence and development of complications of diabe-
tes [ 93 ]. The tendency toward the generation of AGEs is also
favored in long-lived proteins. Long-term hyperglycemia
increases the expression of receptors of glycation end prod-
ucts (RAGE), facilitating the actions of glycosylated prod-
ucts. Numerous studies have conﬁ rmed the increased local
glucose content and accumulation of AGEs in skin and the
increasing amount of AGEs as diabetes progresses. Increased
local glucose content is the dominant feature in patients with
diabetes for only a limited duration of diabetes mellitus,
whereas increased local glucose content and accumulation of
AGEs are observed in those with diabetes for an extended
period of time.
In vitro experiments [ 90 , 94 – 96 ] indicate that kerati-
nocytes typically become polygonal, and brown deposits
are frequently observed in the cytoplasm after advanced
glycation end product-modiﬁ ed human serum albumin
(AGE- HSA) exposure. Decreased nuclear division and
cell viability are also observed. AGEs delayed G1/S phase
transition by the downregulation of cyclin D1 in both tran-
scription and translation levels and upregulation of p21
expression, and led to G2/M phase transition disorder by
downregulation of MPF activity. The percentage of apop-
totic keratinocytes has also been found to be increased, and
the utilization rate of EGF is decreased. The adhesiveness of
cultured endothelial cells and ﬁ broblasts has been observed
to be dramatically increased after high glucose treatment.
The cell volume is enlarged, and metabolism is accelerated.
However, after AGE-HSA exposure, the number of endo-
thelial cells is markedly reduced and vacuolation is also
observed in the cytoplasm. In response to AGE-HSA treat-
ment, the cell volume of endothelial cells and ﬁ broblasts is
markedly reduced, and the cell membranes shrink. Mitosis
in these cells is reduced, and their adhesiveness is weak-
ened. Decreased proliferation and increased apoptosis of
these cells were also found.
The AGE-HSA inhibits capillary morphogenesis for
cultured endothelial cells in Matrigel matrix. Furthermore,
the expression of Ang-2 is enhanced, and that of VEGF is
downregulated. However, Ang-2 small interfering (si)RNA
treatment signiﬁ cantly downregulates Ang-2 in AGE-
treated vascular endothelial cells and restores the formation
of vessel- like structures. These results suggest that the for-
mation of newly generated vessels might be affected by
AGEs via Ang-2. The biological half-life for matrix pro-
teins is generally long, and it is therefore susceptible to
interaction with metabolites, primarily glucose, and other
aldehydes in what is referred to as a glycosylation reaction.
Thus, dermal microenvironment alteration as a result of
ECM glycosylation remains to be investigated. Glycosylated
matrix- induced cell cycle arrest and apoptosis of cultured
dermal ﬁ broblasts were shown [ 97 ], whereas application of
RAGE- blocking antibodies redressed these changes. It may
be concluded that the accumulation of glycosylated ECM
in skin tissue is a critical environmental mediator of cellu-
lar function [ 98 ].
Studies [ 79 , 90 , 94 ] exploring the differential effects of
high glucose content and AGEs on repair cells indicate that
treatment with high concentrations of glucose for 48 h
increases the proliferation of keratinocytes, endothelial cells,
and ﬁ broblasts. However, this was suppressed by 5 days after
treatment. Suppression of proliferation was observed in these
cells when treated with AGEs for 48 h. The detrimental
effects of high glucose and AGEs on repair cells were both
time- and concentration-dependent, and the effects of AGEs
were more deleterious. Studies have also shown that the
9.2 Exploration of the Mechanisms of Impaired Burn Wound Healing in Diabetic Patients

234
tolerance of ﬁ broblasts to high concentrations of glucose and
AGEs is stronger than that of endothelial cells [ 79 , 90 , 94 ],
which is in turn stronger than that of keratinocytes. These
results suggest that hyperglycemia might exert different
pathological effects on different repair cells.
In vitro [ 99 ] it has also been conﬁ rmed that neutrophil
apoptosis decreases, and the production of elastases from
neutrophils and release of reactive oxygen species increase
with higher levels of blood glucose and AGEs.
A prolonged high glucose level leads to the production of
excessive free radical stress and reactive metabolic interme-
diates. Glucose is spontaneously metabolized into AGEs
under aerobic conditions, during which glyoxal and H 2 O 2 are
produced. The increased release of reactive oxygen species
(ROS) from neutrophils is induced by AGEs in a
concentration- dependent manner. In addition, glyoxal pro-
motes the glycosylation of proteins and is toxic to repair
cells. The production of ROS accelerates the increase in
AGEs, which impair cell viability and in turn promote the
formation of ROS and MDA. This is a vicious cycle between
oxidative stress and AGEs independent of high glucose lev-
els. These substances interact with one another, resulting in a
series of cascade reactions [ 100 ].
These works indicate that the accumulation of glucose
and glycometabolic products in skin tissue, as the result of
glycometabolic disorders, contributes to cutaneous environ-
mental alterations in diabetes mellitus, and subsequently
induces abnormal cell behaviors, cytokine alteration, and
matrix modiﬁ cation. We conclude that an abnormal histo-
logical structure and cell biological behaviors in diabetes
mellitus preexist under intact skin, which presents as under-
lying disorder characteristics in diabetic skin. The “underly-
ing cutaneous disorder” in diabetes mellitus might be a
critical risk factor leading to ulceration. The local accumula-
tion of metabolites, which acts as the “switch” in impaired
wound healing in diabetes mellitus, is an important stimulus.
The presentation and conﬁ rmation of these concepts provide
a strong basis for understanding the mechanisms underlying
uncontrolled wound healing in diabetic patients.
9.2.4
Exploration of Therapeutic Strategies
for Refractory Wounds in Diabetes
9.2.4.1 Outline of Research on and Interventions
for Impaired Wounds in Diabetes
Whereas burn wound management in China is advanced, no
effective strategies for managing refractory burn wounds in
diabetic patients are available. On the basis of surgical prin-
ciples, careful debridement, combined with traditional blood
glucose control, is frequently used in clinical practice.
Surgical repair of wounds is occasionally applied, as neces-
sary. Although improvements in surgery have increased
success in wound repair, this is passive, and it is difﬁ cult to
decrease the recurrence of diabetic ulcers.
The mechanisms underlying impaired wound healing in
diabetic patients in China and abroad, especially the devel-
opment of diabetic foot, have been studied extensively, and
progress has been made.
Artery diseases and peripheral neuropathy are important
causes of refractory wounds in diabetic patients. A relation-
ship between biochemical changes in diabetic patients and
diabetic complications has been recognized. The following
types of metabolic remodeling are the main mechanisms
underlying complications mediated by hyperglycemia: the
polyol pathway, the production of AGEs, the PKC pathway,
and the hexosamine pathway. Excessive ROS production
plays an important role in the development of diabetic com-
plications via metabolic remodeling. On the basis of the
above-mentioned studies, researchers have explored inter-
ventions in the treatment of diabetes. These interventions can
be classiﬁ ed into two types: one is aimed at artery abnor-
malities and diabetic neuropathy, including the improvement
of blood supply, application of neurotrophic factors and
growth factors, reduction of local mechanical loading, anti-
infection, and care of diabetic feet; the other is based on bio-
chemical abnormalities and associated pathways to promote
wound healing. Aminoguanidine has been a focus in ﬁ elds
associated with diabetes. Evidence indicates that aminogua-
nidine interrupts the production of AGEs and advanced lipo-
peroxidative products (ALEs) and selectively inhibits
inducible nitric oxide synthase (iNOS), leading to the accel-
eration of wound healing. Aminoguanidine has been used in
phase 2 and phase 3 clinical trials abroad.
In conclusion, studies on the pathophysiological and molec-
ular abnormalities of wounds in diabetes mellitus have furthered
our understanding of the mechanisms underlying diabetes.
However, present therapeutic strategies remain unsatisfactory.
9.2.4.2 Selection of Therapeutic Interventions
In our opinion, the following factors should be considered in
the selection of interventions, given the above-mentioned
research on the mechanisms of diabetes.
1. Strategies should be based on systematic studies of the
mechanisms involved, including previous research
involving all of the factors including cells, ECM, and
growth factors. The effects of pathophysiological changes
in diabetic skin and the effects of metabolic remodeling
induced by abnormalities of glycometabolism on the
development of complications have been explored.
However, these studies possess one notable drawback:
there is a lack of systemic and organic connections among
these various factors.
We studied the mechanisms underlying refractory
wound healing in diabetes mellitus. The results indicated
the presence of preexisting histological and cellular
9 Burn Wound Healing

235
changes in diabetic skin. These abnormalities involve all
factors related to wound healing, and these factors have
their own characteristics and interact with one another.
Furthermore, local high glucose levels and accumulation
of AGEs result from glycometabolic disorders in diabetes
mellitus, and contribute to the biological abnormalities by
altering the cutaneous environment. These abnormalities,
though seemingly different, have common metabolic ori-
gins. These abnormalities are integrated and interactive;
we also term them “underlying cutaneous disorders” in
diabetes mellitus. Thus, interventions should reverse or
diminish this impairment of the skin, leading to improve-
ment of wound healing.
2. The strategies should focus preferentially on the upstream
events of the mechanisms involved. Although artery dis-
eases and peripheral neuropathy are the main causes of
impaired wound healing in diabetes mellitus, they cannot
fully explain the biological abnormalities in diabetic skin.
One explanation may be that artery abnormalities and
diabetic neuropathy result pathologically from complica-
tions. Our analysis of the diabetic skin and the character-
istics of wound healing in diabetes mellitus summarize
the nature of refractory wounds, i.e., impaired wound
healing is a pathological process based on dysmetabolism
and subsequent events. The local accumulation of metab-
olites is upstream of artery diseases and diabetic neuropa-
thy in the course of the diabetes mellitus. Alterations of
cutaneous environment resulting from local high glucose
content and dysmetabolism-induced accumulation of
metabolites are one of the initial factors underlying the
development of refractory wounds. Cutaneous environ-
mental alteration can result in the underlying cutaneous
disorder in diabetes mellitus and exert its inﬂ uence on the
entire process of wound healing, leading to delayed
wound healing or unclosed wounds. Therefore, we should
pay more attention to the cutaneous environmental disor-
ders in the prevention and treatment of refractory wounds
in diabetes mellitus. Interference with upstream events
underlying delayed wound healing may interrupt the
occurrence and development of subsequent events. This
strategy also provides effective and feasible means for the
prevention and treatment of diabetic wounds, which may
provide hope for diabetic patients with refractory wounds.
3. The strategies should not target a speciﬁ c element under-
lying wound healing. Preliminary exploration of the char-
acteristics of skin and wound healing in diabetic patients
has identiﬁ ed the mechanisms underlying refractory
wound healing. Cells, ECM, and growth factors interact
with one another and exert their inﬂ uence on the entire
process of wound healing, resulting in an uncontrolled
network in refractory wounds. Therefore, a single strat-
egy, or strategies aimed at a single pathway, will fail to
achieve desired therapeutic outcomes in wound healing.
Based on our experiments, arginine and aminoguani-
dine exert preventive and therapeutic effects on the under-
lying cutaneous disorders and impaired wound healing in
diabetes mellitus. “The effects of arginine on the underly-
ing cutaneous disorders induced by diabetes” has been
granted a patent (03141583.0, China), and we are applying
for another patent for “The preventive and therapeutic
effects of aminoguanidine on impaired wounds in diabetes
mellitus” (application number: 200310109312.8, China).
9.2.4.3 Mechanisms Underlying the Effects
of Arginine and Aminoguanidine
on Refractory Wounds in Diabetes
1. Improvement of underlying cutaneous disorders in
diabetes
Arginine is a conditionally essential amino acid. Under
normal conditions, arginine can be synthesized to meet
requirements. However, under pathological conditions,
the synthesis of arginine cannot meet the increased
requirements. The relative deﬁ ciency can be identiﬁ ed,
and exogenous supplementation of arginine is necessary
to meet the requirements of wound repair. Arginine exerts
its effects by reducing blood glucose and promoting insu-
lin secretion, and by restoring cellular proliferation, pro-
moting collagen synthesis, and rebuilding the nitric oxide
pathway, leading to the repair of refractory wounds.
The local high glucose content is markedly reduced
after arginine administration, which suggests that it might
rectify the increased local concentration of glucose in the
skin and diminish the pathophysiological changes.
Arginine may also improve hyperglycemia in diabetic rats
via the polyamine pathway. Furthermore, it may stimulate
the release of insulin and increase the sensitivity to insu-
lin, thereby decreasing the blood glucose level.
The layer and structure of the epidermis and dermis in
diabetic rats fed arginine are similar to those of normal
rats. The thickness is normal, and few inﬂ ammatory cells
are found. Arginine is the precursor of proline and
hydroxyproline, both of which are involved in collagen
synthesis. Supplementation of arginine may increase the
local concentration of hydroxyproline and the deposition
of collagen. Recent studies conﬁ rm that arginine exerts its
inﬂ uence on cell physiology via the following pathway.
Arginine is metabolized to polyamine and NO, which can
regulate and stimulate cellular proliferation. In addition,
NO activates intracellular guanylate cyclase to regulate
various metabolic processes. Arginine can also be cata-
lyzed via ornithine to form putrescine and polyamine.
Polyamine is closely associated with cell proliferation
and may stimulate the synthesis of DNA and
RNA. Putrescine also exerts its effects by promoting cell
proliferation. In the diabetic skin tissue, the activity of
iNOS is markedly decreased, and the synthesis of NO is
9.2 Exploration of the Mechanisms of Impaired Burn Wound Healing in Diabetic Patients

236
also downregulated. The deﬁ ciency of NO is one impor-
tant cause of the dysfunction of tissue repair and cell pro-
liferation. Exogenous supplementation of arginine
signiﬁ cantly increases the activity of iNOS and increases
the local concentration of NO, leading to the promotion of
cell proliferation. On the basis of the pharmacodynamic
effects of arginine, it may be used prophylactically in dia-
betic patients to ameliorate impairment of the skin and
reduce the rate of complications in these patients.
2. Preventive and therapeutic effects of aminoguanidine on
refractory wounds
Aminoguanidine has a nucleophilic characteristic and
is a hydrazine compound. During the early stages of dia-
betes mellitus, the afﬁ nity of glycosylation products is
higher for aminoguanidine than for the ξ amino group of
lysine and oxylysine of proteins. Therefore, aminogua-
nidine can combine competitively with early glycosyl-
ation products to generate inactive substitutes that cannot
induce protein crosslinking, leading to the inhibition of
AGE formation. Our studies indicate that the prophylactic
administration of aminoguanidine markedly reduces cuta-
neous AGE accumulation, and the solubility of collagen
is also increased, gradually increasing wound healing.
Furthermore, aminoguanidine can interrupt the vicious
cycle between AGEs and oxidative stress and diminish
the toxic effects of H 2 O 2 on ﬁ broblasts.
9.2.4.4 The Prospect of Interventions Aimed
at Refractory Wound Treatment
in Diabetic Patients
Diabetes mellitus is a main threat to human health in the twenty
ﬁ rst century. The prevalence increases with economic develop-
ment and increasing living standards. The World Health
Organization estimates that 177 million patients have been
diagnosed with diabetes worldwide, and this number will reach
300 million by 2025. Among these patients, 75 % are in devel-
oping countries including China and India. The number of dia-
betic patients in China is rapidly increasing. Statistical data
indicate that the prevalence was 0.67 % in 1980 and 3.12 % in
1996, and it is predicted to grow to 38 million by 2025.
Refractory wounds are one of the most important compli-
cations in diabetes. It is reported that 15 % of diabetic
patients have refractory wounds. In diabetic patients, burn
wounds, traumatic wounds, and surgical wounds often show
delayed healing or remain unclosed. At present, the treat-
ment of refractory wounds in diabetic patients is extremely
difﬁ cult. Statistical data suggest that diabetic patients with
foot ulcers account for 1.25 million bed-days per annum in
English hospitals, costing 325 million pounds. In the United
States, diabetic patients with foot ulcers account for 20 % of
diabetic patients, and diabetic patients who have undergone
amputation account for 50 % of patients with nontraumatic
amputation.
In China, the numbers of refractory wounds in diabetic
patients are increasing, and preventive as well as therapeutic
strategies are not well developed. Diabetic patients with
refractory wounds and those at a high risk of refractory
wounds do not receive speciﬁ c treatment or effective health
education. On the contrary, most Western developed coun-
tries pay more attention to the prevention and therapy of
refractory wounds in diabetic patients, and principles of
diagnosis, treatment, prevention, and nursing have been set.
A number of studies relating to preventive and therapeutic
interventions have been launched in these countries. China
has lagged behind these developed countries in this ﬁ eld.
On the basis of systematic explorations of the mechanisms
underlying refractory wounds in diabetic patients and strate-
gies involving independent intellectual property rights, in-
depth studies on the mechanisms, including the preventive and
therapeutic effects of arginine and aminoguanidine on refrac-
tory wounds, as well as their optimized application, will accel-
erate preclinical trials and the establishment of systematic and
normalized principles of diagnosis and treatment. These fac-
tors are not only of great interest with respect to academic
research, they also have bright market prospects.
9.3
The Defect of Dermal Template
in Wounds Contributes to Scar
Formation
Shuliang Lu, Yingkai Liu, Xiqiao Wang, and Jiang Yuzhi
9.3.1
Introduction
The process of wound healing involves cells, cytokines, and
the ECM. Previous studies revealed that scar formation cor-
related mainly with the change in the cells, cytokines, and
ECM in wound healing. However, recent research has shown
that cells, cytokines, and ECM function merely as “partici-
pants” or “executors” in wound healing. The changes in
these elements may be a “cascade” reaction in wound heal-
ing and are not the initiators of scar formation.
Thus, what are the initiators of scar formation? Some
clinical evidence aroused our interest in this subject:
1. A wound of a superﬁ cial burn injury leaves no scar or only
a minor scar after wound healing, whereas a wound with a
deep burn injury results in hypertrophic scar formation.
2. In addition, when the dermal substitute is applied to the
wound, the scar formation is greatly reduced after healing.
3. Moreover, the frostbite wound, in which the dermal struc-
tures are well preserved, leaves almost no scar formation
after wound healing.
The phenomenon indicates that the scar formation may be
correlated with the amount of dermis. Thus, we conducted a
series of experiments to investigate the relationship between
9 Burn Wound Healing

237
dermal defect and scar formation, and the possible mecha-
nism by which dermal tissue affects wound healing.
9.3.1.1 Relationship Between a Dermal Defect
and Scar Formation
To better understand the relationship between a dermal
defect and scar formation, we studied scar formation under
dermal defects with different thicknesses, and also studied
scar formation when dermal tissue with various thicknesses
was transplanted on an equal dermal defect wound [ 101 ].
The results revealed that the more of dermal tissue was lost
in the wounds, the higher the Vancouver score to evaluate
scar formation, and showed a positive correlation between
the thickness of the dermal defect and the scar formation ( r
=0.597, p < 0.01). In addition, when a wound with a dermal
defect was subjected to self-dermal grafting, the postopera-
tive Vancouver score decreased. The greater the quantity of
dermal tissue that was transplanted, the smaller the scar was
that formed, which showed a negative correlation between
the thickness of grafted skin and scar formation ( r = −0.569,
p < 0.01; Table 9.34 ).
The dermis transplantation inhibited scar formation, but
can transplantation of the dermal substitute in which only the
collagen structure was preserved also inhibit scar formation?
9.3.1.2 Effect of Dermal Substitute
Transplantation on Wound Healing
To investigate the effect of dermal substitute on wound heal-
ing, we created an animal wound model as natural healing,
thin skin graft transplantation, full skin graft transplantation,
and composite transplantation (thin skin graft + dermal sub-
stitute), and compared the differences in histological fea-
tures, biomechanical compliance, and cellular function of
wound healing for 20 weeks. In clinical experiments, the
wounds after eschar excision in burn patients were chosen
for thin skin grafting and composite transplantation, and then
to investigate histological, morphological, and cellular bio-
logical differences respectively.
Animal study demonstrated that dermal graft transplanta-
tion could accelerate tissue remodeling [ 102 ]. In the early
stages of wound healing, the morphology of ﬁ broblasts was
spindle-shaped and the collagen arrangement was parallel to
the skin surface, then the ﬁ broblast shape transformed into a
polygonal stellate, and the collagen arrangement turned out
to be the interweaving form in later stages, which is more
similar to that in normal skin. This phenomenon was most
pronounced in full skin grafting, and the composite trans-
plantation was almost similar to that of full skin grafting,
while the ﬁ broblast shape and the collagen arrangement in
natural healing and thin skin grafting were identical in early
and later stages of wound healing, which is more similar to
that in a hypertrophic scar (Fig. 9.5 ).
In addition, biomechanical compliance of composite
transplantation was almost similar to that in full skin graft-
ing, which had good ﬂ exibility after wound healing, while
the biomechanical compliance of natural healing and thin
skin grafting was inferior (Fig. 9.6 ).
Furthermore, compared with full skin grating and com-
posite transplantation, the expression of α-SMA, TGF-β1,
ﬁ bronectin (FN), and integrin α 2 β 1 was higher in natural
healing and thin skin grafting, which correlate with scar for-
mation (Tables 9.35 , 9.36 , 9.37 , 9.38 , and 9.39 ) [ 103 ].
The results of clinical experiments were similar to those
of animal experiments. Compared with thin skin grafting,
the composite transplantation could reduce collagen syn-
thesis and deposition, suppress the differentiation of ﬁ bro-
blasts toward myoﬁ broblasts, inhibit the proliferation of
endothelial cells, downregulate the expression of TGF-β1
and its receptors TGF-β RI, II, and Smad3. In addition, the
composite transplantation also promoted apoptosis in the
later stages of wound healing [ 104 – 109 ] (Tables 9.40 , 9.41 ,
9.42 , 9.43 , and 9.44 ). Therefore, the dermal tissue defect in
natural healing and thin skin grafting cause scar formation
after wound healing, and could be improved by composite
transplantation.
Why could the dermal substitute act as dermal tissue to
affect wound healing aiming at scarless healing? Does the
three-dimensional (3D) structure or the components in it
play a key role in regulating wound healing? To address this
question, we conducted further studies.
Table 9.34 Comparison of Vancouver score after 6 months x
s
±
(
)
Group
Wound number
Depth of dermal defect (cm)
Thickness of grafted dermis (cm)
Vancouver score of the scar
A1
9
0.146 ± 0.022
0
0.182 ± 0.050
A2
9
0.163 ± 0.035
0.138 ± 0.084
0.111 ± 0.033
B1
9
0.456 ± 0.150*
0
3.714 ± 0.498 Ⴃ
B2
9
0.656 ± 0.277*
0.152 ± 0.071
1.050 ± 0.057 Ⴍ
B3
9
0.603 ± 0.122*
0.558 ± 0.095 #
0.636 ± 0.055 #
Note: A1 donor sites of thin skin without grafting, A2 donor sites of thin skin with grafting, B1 donor sites of thick skin without grafting, B2 donor
sites of thick skin with thin thickness skin grafting, B3 donor sites of thick skin with thick skin grafting
* p < 0.05 compared with A; # p < 0.05 compared with A2 and B2; Ⴃ p < 0.01 compared with other groups; Ⴍ p < 0.05 compared with A2
9.3 The Defect of Dermal Template in Wounds Contributes to Scar Formation

238
Fig. 9.5 Comparison of changes in collagen arrangement during
wound healing from the 1st week to the 20th week postoperatively (HE
×400). ( a – d ) Comparison of collagen arrangement in the ﬁ rst week
after surgery; ( e – h ) comparison of collagen arrangement in the 20th
week after surgery; ( a , e ) naturally healed wound; ( b , f ) self thin skin
grafting; ( c , g ) composite skin grafting; ( d , h ) full skin grafting. One
week after surgery, collagen in the granulation tissue was thin and
aligned parallel to the skin surface. While in the 20th week after sur-
gery, the nascent collagen became thick and interwoven, and aligned,
similar to that in normal skin. This phenomenon was most obvious in
full skin grafting. While the composite skin grafting was almost similar
to that of full thick skin grafting, the thin skin grafting was inferior
a
b
c
d
e
f

9 Burn Wound Healing