Axonal Regeneration and Remyelination Evaluation of Chitosan/Gelatin-Based Nerve Guide Combined with Transforming Growth Factor-β1 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 artificial 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 constructed with collagenous matrices as a vehicle for Schwann cells and transforming growth factor-beta 1 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 immunohistochemistry 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 connective 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 analysis are further provided in support of improving axonal regeneration and remyelination. A designed graft incorporating all of the tissue-engineering strategies for peripheral nerve regeneration may provide great progress in tissue engineering for nerve repair.