[Study on the proliferation of epidermal cells of wound edge in deep partial thickness scald injury in rat].
OBJECTIVE
To investigate the rule and possible mechanism of epidermal proliferation in wound edge of deep partial thickness scald injury in rat.


METHODS
Twenty-four Sprague-Dawley rats inflicted with deep partial thickness scald were randomized into pre-scalding, 3 post-scalding day (PSD), 7PSD and 14PSD groups, with 6 rats in each group. Skin specimens from the wound edge were harvested for the observation of the histological characteristics of the epidermis. Cell cycles of epidermal cells were analyzed with flow cytometry. The expressions of cyclin D1, cyclin B1, cdk4 and the histone H1 kinase activity of MPF in epidermal cells were determined by Western blotting.


RESULTS
Augmentation of nuclei and nucleoli was found in the epidermal cells from the wound edge in 3PSD group, while increased number of epidermal cells with obviously augmented nuclei and nucleoli were found in 14PSD group. The percentage of the cells in S phase increased in 14 PSD group. The percentage of epidermal cells in G2/M phase began to increase in 3PSD group, and that in 7PSD (4.5 +/- 0.6) and 14PSD (5.4 +/- 1.0) groups were obviously higher than that in pre-scalding group (2.9 +/- 1.1, P < 0.05). The expression of cyclin D1 increased significantly in 3PSD group. The expression of cdk4 decreased in 3PSD group, but began to increase in 14PSD group. There was no difference in the expression of cyclin B1 among groups. The MPF activity was significantly increased in 14PSD group.


CONCLUSIONS
There was enhanced DNA synthesis and mitosis in epidermal cells of rats with deep partial scald during early post-scald stage, and active proliferation of epidermal cells was observed on 14PSD. The expression of cyclinD1/cdk4 complex and the activity of MPF increased since 14PSD, indicating that there was a special regulative pattern during wound healing.
Xie
Ting
T
Department of Burns, Ruijin Hospital, Shanghai Second Medical University, Shanghai 200025, P.R. China.
Lu
Shu-liang
SL
Niu
Yi-wen
YW
Ge
Kui
K
Tian
Ming
M
Dong
Wei
W
Qing
Chun
C
Shi
Ji-xiang
JX
D000818:Animals; D002056:Burns / Q000473:pathology*; D002453:Cell Cycle; D049109:Cell Proliferation; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D017695:Soft Tissue Injuries / Q000473:pathology*; D014945:Wound Healing