GLYCOSAMINOGLYCAN COMPOSITION OF UNINJURED SKIN AND OF SCAR TISSUE INFETAL, NEWBORN AND ADULT SHEEP

Few details are available on the heterogeneity of glycosaminoglycans ( GAGs) in healing fetal wound tissue. We used a sensitive assay for hex osamines to examine changes occurring in the development of normal she ep skin and of wound healing tissue in PVA sponges inserted subcutaneo usly at different stages of gestation. It was assumed that glucosamine was derived mainly from hyaluronan and galactosamine mainly from derm atan sulphate and chondroitin sulphate. Hexosamine-containing tissue i nfiltrating the sponges was deposited more rapidly in the first week t han in the second week. Three days after wounding, approximately 70% o f the total GAGs in wound tissue was hyaluronan. The proportion of hya luronan then fell progressively and by the 14th day contributed 57% to the total GAGs. In uninjured skin the contribution of hyaluronan to t he total GAGs fell progressively with increasing fetal maturity, the l evel being 70% at 75 days gestation, but only 35-40% in newborn or adu lt skin. At no stage of develoment was there a sudden change in GAG co mposition suggestive of a transition from regeneration to scar formati on. It is concluded that hyaluronan may play an important role in the biochemical sequence leading to collagen fibrillogenesis and mature sc ar formation.