Biology of fetal wound healing: collagen biosynthesis during dermal repair

The rapid restoration of tissue integrity and breaking strength in healing fetal wounds is mainly a function of fetal wound collagen. In this study, the fetal and adult tissue responses to injury were characterized in terms of changes in collagen biosynthesis. Linear wounds and unwounded skin were incubated with radioactive proline, and collagen synthesis was measured as isotope incorporation into collagenase-sensitive protein. Likewise, noncollagen protein synthesis was represented by isotope incorporation into collagenase-resistant protein. Adult wounds demonstrated a preferential stimulation of collagen as compared with noncollagen protein synthesis after wounding. In contrast, both collagen and noncollagen protein synthesis were significantly elevated in the fetus during the first 5 days postwounding. Despite marked increases in fetal wound collagen synthesis above both unwounded fetal skin and adult wound levels, fetal wounds exhibited no evidence of excessive collagen deposition or scar formation after wounding. These findings suggest that the fetal response to tissue injury is a function of the distinctive qualities of fetal fibroblasts associated with the extracellular wound matrix and may involve rapid collagen turnover and degradation.