ANALYSIS OF THE MECHANISM OF BLEOMYCIN-INDUCED CUTANEOUS FIBROSIS IN MICE

Abstract

Mouse skin assays for collagen, determined as hydroxyproline, were carried out on a bleomycin-treated group and on untreated controls. Animals receiving bleomycin showed cutaneous collagen levels approximately 1.75 time higher than those exhibited by the untreated controls. With respect to the ratios of hydroxy proline in soluble collagen fraction to cutaneous total hydroxy proline content, the bleomycin-treated group displayed a roughly 50 per cent decrease in neutral salt soluble fraction and a slight diminution of the acid soluble fraction, as compared with the untreated controls. The findings indicate a significant increase in insoluble collagen content in the skin of mice receiving bleomycin. In an attempt to clarify the mechanism of collagenolysis by the anticancer antibiotic, cutaneous tissue specimens taken from animals treated with the antibiotic were grown in vitro, and crude collagenase preparations isolated from tissue cultures assayed radiologically, using 14C-glycine labelled collagen as the substrate. Lower cutaneous collagenolytic activity was observed in mice treated with bleomycin.