A nerve conduit filled with Wnt5a-loaded fibrin hydrogels promotes peripheral nerve regeneration

Aims Peripheral nerve injury is a significant clinical problem with a substantial impact on quality of life, for which no optimal treatment has been found. This study aimed to analyze the effect and mechanism of Wnt5a-loaded fibrin hydrogel on a 10-mm rat sciatic nerve defect. Methods The Wnt5a-loaded fibrin hydrogel was synthesized by mixing a Wnt5a solution with thrombin and fibrinogen solutions. The loading capacity and release profile of Wnt5a-loaded fibrin hydrogel and the effect of Wnt5a on Schwann cells were evaluated in vitro. We also assessed the in vivo repair status via histological analysis of the regenerative nerve and gastrocnemius muscle, electrophysiological examination, gait analysis, and muscle wet weight. Results We developed a nerve conduit filled with Wnt5a-loaded fibrin hydrogel (Fn) as a sustained-release system to repair a 10-mm rat sciatic nerve defect. In vitro, Wnt5a could promote SC proliferation and the gene expression of vascular endothelial growth factor (VEGF), nerve growth factor (NGF), and cholinergic neurotrophic factor (CNTF), as well as the protein secretion of VEGF and NGF. In vivo, the Wnt5a/Fn group was superior to the hollow, fibrin hydrogel, and Wnt5a groups in terms of axonal growth, myelination, electrophysiological recovery, target organ innervation, and motor function recovery 12 weeks after the operation. Conclusion The Wnt5a/Fn nerve conduit can promote peripheral nerve defect regeneration, with potential clinical applications. The mechanism for this may be the facilitation of multiple neurotrophin secretion, combining vascularization and neurotrophic growth cues.