bFGF-chitosan scaffolds effectively repair 20 mm sciatic nerve defects in adult rats.

The repair of peripheral nerve injury is still a great challenge in clinic. Autologous nerve transplantation is the gold standard for the treatment of long-distance peripheral nerve defects, but this method remains associated with high morbidity of the donor site and lack of matching donor. In this study, a novel chitosan scaffold loaded with control-released bFGF was used to repair 20 mm sciatic nerve defects in adult rat. The ultrastructure of bFGF-chitosan scaffold was observed by scanning electron microscope. The tensile tester and nano-indentation were used to evaluate its mechanical properties. Cholera toxin B-subunit (CTB )tracing, sciatic nerve function index(SFI), electromyography, immunofluorescence staining of regenerated nerve and motor endplate were used to evaluate the regeneration of sciatic nerve in rats. The results showed that the structure and mechanical properties of bFGF-chitosan scaffold was beneficial to the regeneration of sciatic nerve. At 12 weeks after operation, bFGF-chitosan scaffold facilitated sciatic nerve regeneration in rat. CTB successfully crossed the sciatic nerve defect area to reach the cell body of sciatic nerve. The motor endplate was reconstructed, thus promoting the behavioral recovery. These findings suggest that the bFGF-chitosan scaffold provides an effective means of repairing 20 mm sciatic nerve defects and shows great potential for clinical application.