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Tissue repair in the mammalian fetus is fundamentally different from healing process of the adults. In the adults, an injured tissue is repaired by collagen deposition, collagen remodeling, and an eventual scar formation. On the other hand, fetal would healing seems to be a more regenerative process with minimal or no scar formation. There are many different findings in the would healing processes between the fetuses and the adults. Although the biochemistry and environment of adult wound healing have been reported previously, the endeavor of investigators of wound healing still continues to detect the mechanism of scarless wound healing in fetus.The purpose of this study is to evaluate the hypothesis that the growth factor may affect inflammatory reaction and fibroblast production. Under this hypothesis, we examined inflammatory reaction, fibroblast production, and collagen deposition subjected to subcutaneous pocket through incisional wound on day 22 of gestation(term : 30-31 days). After implants(1.2 cm in length and 0.1 cm in diameter, perforated silicone tube which contain polyvinyl alcohol sponge) were inserted into the subcutaneous pocket on the dorsum of fetuses and adults, fetuses were returned immediately to the uterus. And then the microscopic analysis of the implants was done on the third, fifth, and seventh day after insertion of implants. The microscopic findings of the implants from the fetal rabbits showed lower degree of inflammatory infiltrations, fibroblast production, and collagen deposition than those from the adult rabbits. To demonstrate the effect of the platelet derived growth factor(PDGF) on these reponses, we added PDGF to the implant which would be inserted into fetus and compared the outcome with control groups. The microscopic findings of the PDGF treated implants showed higher degree of inflammatory infiltration, fibroblast production, and collagen deposition than those of the control fetus group, which were similar to control adult group.
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