Influence of local fibrin deposition on granulation tissue formation. A biochemical study in the rat.

A recently developed method for occlusion of fistulas with a fibrin clot initiated studies of the effects of deposited fibrin on granulation tissue formation. Perforated Teflon cylinders, empty or fibrin-filled, were implanted subcutaneously in rats for 2, 3 and 4 weeks and the composition of the ingrowing granulation tissue was followed by sequential biochemical analysis. The concentration of fat and water and the cellularity, measured as DNA concentration, were the same throughout the period studied in the granulation tissue from cylinders implanted empty and fibrin filled. After 2 weeks of implantation, the collagen concentration was higher in fibrin-filled cylinders than in cylinders implanted empty. The higher collagen concentration was explained by a higher proportion of mature collagen-synthesising cells. After 3 and 4 weeks of implantation there was no difference in the collagen concentration between cylinders implanted empty and fibrin filled.