title: Formaldehyde as a pre-treatment for dermal collagen heterografts.
abstract: The preparation, stability both in vitro and in vivo and resistance to bacterial collagenase of trypsin-purified pig dermal collagen cross-linked with a range of concentrations of formaldehyde in phosphate-buffered saline, was studied using 14C-labelled formaldehyde as a tracer. Washing in phosphate-buffered saline at 37 degrees C produced rapid loss of formaldehyde over 6 weeks before stability was reached. After 19 weeks washing, 12-20% of the initial radioactivity remained, representing 6, 18 and 35 mumol formaldehyde/g of collagen after 21 days reaction with 0.1, 1 and 5% formaldehyde, respectively. Collagen, incorporating stable-bound formaldehyde arising from reaction with formaldehyde in concentrations of 0.5% or over, was totally resistant to bacterial collagenase. The stabilizing effect of formaldehyde cross-linking was also demonstrated by implants of fibrous pig dermal collagen in rats. After 8 weeks a significant constant amount of formaldehyde was retained in all implants. There was no net loss of mass over a 24 week period when pre-treated with 1% formaldehyde but some loss when pre-treated with 0.1% formaldehyde.
mesh_terms: D000818:Animals; D003094:Collagen / Q000378:metabolism; D003432:Cross-Linking Reagents; D005557:Formaldehyde; D007700:Kinetics; D008297:Male; D003012:Microbial Collagenase / Q000378:metabolism; D051381:Rats; D012867:Skin / Q000032:analysis; D013552:Swine; D014357:Trypsin
chemical_list: D003432:Cross-Linking Reagents; D005557:Formaldehyde; D003094:Collagen; D014357:Trypsin; D003012:Microbial Collagenase