The influence of locally deposited fibrin on the biomechanical properties of developing granulation tissue in rats.

A recently developed method for the occlusion of fistulas with a fibrin clot has stimulated studies concerning the effects of deposited fibrin on the formation of granulation tissue (g.t.). In this study the influence of artificially implanted fibrin on the biomechanical properties of developing g.t. was investigated in rats. Perforated Teflon cylinders either empty or fibrin filled, were implanted subcutaneously for two weeks. The g.t. from fibrin filled cylinders was found to adhere significantly better to the cylinder walls which is an important property in the case of fistula closure with fibrin. Mechanical testing, however, showed that the maximum load and the maximum strain were significantly higher in cylinders implanted empty. However, the collagen concentration was no higher in cylinders implanted empty suggesting that in the newly formed g.t. studied, factors other than the collagen concentration determined the strength of the tissue.