Effect of the environment on fetal skin wound healing

Skin wound healing has been shown to be a different process in the fetus than in the adult animal. Some of these differences have been attributed to the unique fetal environment (i.e., amniotic fluid). The aim of the present study is to compare fetal skin healing in intraamniotic and extraamniotic wounds. A fetal rabbit model has been used in which three types of skin wounds were induced on 23-day-old fetuses in contact with either amniotic fluid or maternal peritoneal fluid. The wounds consisted of a sutured skin incision, a nonsutured incision, and an electrocautery burn. Seven days later all wounds were examined mechanically (scar resistance), biochemically (collagen and noncollagen protein concentration), and histologically. Biochemical and growth factor studies of both environments, the amniotic and the peritoneal fluids, were also conducted. The results showed excellent healing by first intention and absence of healing by second intention in both environments, greater scar resistance in the intraperitoneally positioned fetal wounds, and a higher concentration of insulin-like growth factor-1 (IGF-1) in the peritoneal fluid than in the amniotic fluid. It can be concluded that fetal skin wounds in contact with peritoneal fluid show the same healing pattern as in the natural fetal environment (amniotic fluid). The higher concentration of IGF-1 in the peritoneal fluid suggests that this growth factor, through its relationship with the growth hormone, plays a role in increasing the scar resistance of fetal skin wounds in contact with maternal peritoneal fluid.