Axonal Regeneration and Remyelination Evaluation of Chitosan/ Gelatin-Based Nerve Guide Combined with Transforming Growth Factor-b1 and Schwann Cells

Despite efforts in peripheral nerve injury and regeneration, it is difficult to achieve a functional recovery following extended peripheral nerve lesions. Even if arti- ficial nerve conduit, cell components and growth factors can enhance nerve regeneration, integration in peripheral nerve repair and regeneration remains yet to be explored. For this study, we used chitosan/gelatin nerve graft con- structed with collagenous matrices as a vehicle for Schw- ann cells and transforming growth factor-b1 to bridge a 10-mm gap of the sciatic nerve and explored the feasibility of improving regeneration and reinnervation in rats. The nerve regeneration was assessed with functional recovery, electrophysiological test, retrograde labeling, and immu- nohistochemistry analysis during the post-operative period of 16 weeks. The results showed that the internal sides of the conduits were compact enough to prevent the connec- tive tissues from ingrowth. Nerve conduction velocity, average regenerated myelin area, and myelinated axon count were similar to those treated with autograft (p ( 0.05) but significantly higher than those bridged with chitosan/gelatin nerve graft alone (p 0.05). Evidences from retrograde labeling and immunohistochemistry anal- ysis are further provided in support of improving axonal regeneration and remyelination. A designed graft incor- porating all of the tissue-engineering strategies for peripheral nerve regeneration may provide great progress in tissue engineering for nerve repair.