COLLAGEN CONTENT OF UNINJURED SKIN AND SCAR TISSUE IN FETAL AND ADULTSHEEP

Total collagen content (measured as hydroxyproline) and Type I/Type II I ratio (measured by SDS-PAGE) of normal skin and of scar tissue devel oping within a subcutaneously implanted polyvinyl sponge have been det ermined in 75, 90 and 120-day foetal lambs and adult sheep and correla ted with histological appearances of the same tissues. Collagen conten t of normal skin is low at 75 days and rises progressively until birth when it is about half the adult level. The proportion of Type III in normal skin is highest at 75 days and falls progressively as the foetu s develops. With implanted sponges the time course of changes in colla gen content and I/III ratio are similar in all foetal groups and in ad ult sheep. Collagen content is low 3 days after implantation and rises progressively to reach a similar level in all groups by 28 days. The levels correlate closely with the amount of collagen visible in histol ogical sections. The proportion of Type III is highest at 3 days in al l groups and falls progressively as the newly formed tissue matures. T he findings confirm our previous study of the healing of skin wounds t hat from as early as 75 days gestation foetal lambs can form scar tiss ue in a similar way to adult sheep.