Confocal imaging of Schwann-cell migration along muscle-vein combined grafts used to bridge nerve defects in the rat

Schwann cells guide axonal regrowth during peripheral nerve repair. In a ca se of a nerve lesion with substance loss, a graft conduit is necessary to e nable axons to reach the distal nerve stump, If a non-nervous autograft is used, the question arises as to the presence and origin of Schwann cells al ong the grafted tube. We addressed this issue using a tubulization techniqu e based on the use of an autologous vein filled with fresh skeletal muscle for the repair of sciatic nerve defects in the rat. We showed that both end s of the graft were early and progressively colonized by a number of glial fibrillar acid protein-immunopositive and S-100 immunonegative cells, an im munocytochemical pattern typical of immature Schwann cells. These cells, wh ich were located in the interstice between grafted skeletal muscle fibers, are mainly organized into long chains oriented along the main axis of the g raft and progressively colonize all the graft, Schwann cells coming from th e distal nerve end are suitable for being responsible for guiding regenerat ion of nerve fibers along the graft toward the correct periphery (tissue sp ecificity). (C) 2001 Wiley-Liss, Inc.