RESUMO
Experimental incised wounds 8 mm in diameter were made on the right side of the back of 48 rats under anesthesia using aseptic technique. All animals were randomly divided into 12 groups according to the time of wound biopsies which were taken immediately after skin cutting, lh,12h,24h,2,3,4,5,6,7,8,9 and 10 days after wounding.One rat of each group was given colchicine before animal sacrifice in order to observe cell mitosis. Skin specimens were fixed in 10% formalin,embeded in paraffin and sectioned for HE stain,Gorden and Sweet stain for reticular fiber,Weigert stain for elastic fiber,PTAH stain for fibrin and Van Gieson stain.Macroscopically, wounds were getting smaller daily,and reduced in size markedly on the 6～7th day. The histologic changes were as follows:Acute inflammation on the wall of wounds occurred 1h after skin cutting;profuse fibrin exudation at the top of the base and on the wall of wounds at 24h;new capillary formation and regeneration of the epidermis on the 2nd day;granulation tissue formation and collagen fiber deposition on the 3rd day;small artery formation in the granulation tissue on the 4～5th day;granulation tissue maturation and the regenerating tissue covering the whole wound area on thd 6～7th day;the scar formation and contraction on the 8～9th day;further sear contration on the 10th day.The epidermis regenerated from the proliferation of the epidermis at the edge of the wound with the speed of 1.23mm/day. The regeneration of the epithelium proceeded under the necrotic tissue on both the wall and at the base of wounds. The mechanism of the wound contraction was discussed.