We have compared the effect of the synthetic skin substitute, Biobrane with that of the full-thickness skin graft on wound contraction in a rat wound model. The purpose of this experimental study is to evaluate indirectly the role of collagen and myofibroblasts in wound contraction. Twenty five adult Sprague-Dawley rats (250-260 gm) were used as experimental animals. Two separate wounds, sized 2.5×2.5cm respectively, were hade on the back of the rats by excision through the panniculus carnosus, and the defects were covered with Biobrane and the autologous full-thickness skin graft.
Computer and digitizer were used to estimate the changes in the surface area of the wounds at 5 days, 1, 2, 3, and 4 weeks after the operation. To quantify the myofibroblasts, we used the actin-immunoperoxidase method and the light microscopic observation at 1, 2, 3 and 4 weeks after the operation.
Wound contraction phenomenon was observed both in Biobrane-covered wounds and in full-thickness skin grafted wounds by the 4th week. And the degree of wound contraction was similar in both groups. But at the 4th weeks, wound contraction in Biobrane-covered wounds was severer than in full-thickness skin grafted wounds. Myofibroblasts were observed most frequently in the wounds during the 3rd week, and the degree of wound contraction was maximum. So we could correlate the frequency of myofibroblasts’ appearance with the degree of wound contraction.
From the above experimental results, we could suggest that
1) collagen may be one of the major inhibitors of wound contraction, and
2) myofibroblast may be an active participant in wound contraction.
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