Axonal outgrowth in muscle grafts made acellular by chemical extraction

Purpose: To compare nerve regeneration in autologous detergent extracted an d freeze-thawed muscle grafts and to electrophoretically characterize the g rafts. Methods: Autologous acellular muscle grafts were created either by freeze/t hawing or by detergent extraction and then used to bridge a 10 mm gap in ra t sciatic nerve. The autologous grafts were compared with respect to protei n content, using electrophoresis preimplantation, and axonal outgrowth, Sch wann cell and macrophage content, using immunocytochemistry (neurofilaments , S-100 protein, ED 1 macrophages) at 5-20 days postimplantation. Results: The extracted muscle grafts were elastic, but the amount of severa l proteins was reduced and laminin was still present at a position of basal laminae of the muscle fibers. The freeze/thawed grafts were brittle and la cked elasticity, but resulted in minor changes in major proteins. The axons regenerated through both types of grafts (initial delay 6 days and rate 0. 7-0.8 mm/day), which shrunk in length by 25%. There were no apparent differ ences with respect to Schwann cells and macrophages. Conclusions: The results suggest that detergent extracted mucle tissue, in which some basal lamina proteins remain but cells are removed, could presen t a new favourable option for nerve grafting.