In the present study, both the protein levels of BDNF and NGF were significantly higher in the L-CCH+OW group than those in the L-CCH group at 2 weeks after surgery, which might be, at least in part, responsible for the improved nerve regeneration in the L-CCH+OW group. Despite the finding that elevated protein levels of BDNF and NGF was observed in the L-CCH+OW group, the source of BDNF and NGF was not identified in the present study. SCs regain the ability of synthesizing neurotrophic factors after peripheral nerve injury, thus are probably the main source of BDNF and NGF. In addition, omentum might be served as a pool for BDNF. It has been shown that BDNF expression was noted in vascular endothelial cells, which were abundantly found in omentum. The omentum implanted at the local site of nerve scaffold might contribute to the up-regulation of BDNF observed in the LCCH+OW group. The mechanism underlying the up-regulated expression of BDNF and NGF needs to be clarified in the future studies. Large peripheral nerve defects are frequently caused by trauma, and patients with those injuries should be advised to seek emergency surgery immediately. Otherwise, the dispersed axonal growth would lead to neuroma formation, and the atrophy of denervated target organs would increase the risk of permanent disability. Autologous omentum is not only free of ethical issues but also easily harvested through laparoscopic techniques without many intraabdominal complications associated with laparotomy. In addition, omentum is easy to integrate with local sites and avoid questions regarding immunogenicity, thus exhibits therapeutic potential in the immediate repair of large nerve defects while combined with nerve scaffolds. The encouraging outcomes in the present study indicate that the combined usage of omentum and nerve scaffolds, if further confirmed in larger animals and even humans, may serve as a potent alternative to nerve autografts. Moreover, nerve autograft contains Schwann cells and basal lamina micro-channels, which are responsible for axonal regeneration achieved by nerve autograft, while the longitudinally oriented micro-channels within the L-CCH scaffold and omentum wrapped around the channels might largely account for axonal regeneration achieved by the omentum-wrapped LCCH scaffold. Although the nerve regeneration achieved by omentum-wrapped L-CCH scaffold is not superior to that by nerve autograft, it is still encouraging that these two grafts achieved similar performance in promoting nerve regeneration in the present study. It can be hypothesized that seeding SCs and incorporating neurotrophic factors into the omentum-wrapped LCCH scaffold may achieve better nerve regeneration and functional recovery than nerve autograft, which will be investigated in our future studies. In conclusion, the combined usage of omentum and the L-CCH scaffold described here has several potential advantages over other strategies for promoting large nerve defect regeneration. Firstly, the L-CCH scaffold is relatively easy to prepare, handle, store, and sterilize. Secondly, the longitudinally oriented micro-channels in the L-CCH scaffold are capable of guiding the linear growth of Reversine regenerated axons, and the interconnected porous structure may facilitate penetration of blood vessels.