Rat sciatic nerve regeneration across a 10-mm defect bridged by a chitin/CM-chitosan artificial nerve graft

Chitosan as a natural bioactive biopolymer has been commonly employed in guidance conduit for repairing peripheral nerve injury, due to its excellent properties of low toxicity, antibacterial properties, high biocompatibility and biodegradability. In this study, chitin and CM-chitosan were prepared from pharmaceutical grade chitosan. Moreover, a novel composite chitosan-based nerve graft comprising microporous chitin-based conduit and internal CM-chitosan fiber was constructed and applied to bridge sciatic nerve across a 10-mm defect in SD rats. The chitin/CM-chitosan artificial nerve graft could promote the proliferation of rat Schwann cells (RSC96) with good cell biocompatibility. After implantation, the artificial nerve graft showed slow degradation. No apparent toxicity was observed, and tissue inflammation was very slight after implantation, indicating favorable bio-safety of the nerve graft. Furthermore, the chitin/CM-chitosan artificial nerve graft could effectively promote restoration of damaged neurons with similar effect compared to the autograft. In conclusion, the composite biodegradable chitin/CM-chitosan nerve grafts possessed favorable biocompatibility and good potential in repairing peripheral nervous injury.