3H-collagen turnover in non-cross-linked and aldehyde-cross-linked dermal collagen grafts

Using trypsin-purified rat dermal collagen labelled with tritiated hydroxyproline and proline, a study has been made of hydroxyproline turnover in non-cross-linked and glutaraldehyde- and formaldehyde-cross-linked collagen when implanted s.c. in unlabelled isogenic rats. Grafts cross-linked with 0.01% glutaraldehyde maintained their collagen mass over a 22-week period, loss of original collagen being balanced by the gain in new collagen (22% at 22 weeks). Cross-linking with 5% formaldehyde temporarily inhibited collagen loss as compared with non-cross-linked grafts. However, at 22 weeks both had lost some 30% of their collagen mass, the gain of new collagen (some 8%) only partially compensating for the loss of original implant collagen.