gms | German Medical Science

Introduction: Peripheral nerve injury is a common and devastating complication after trauma and can cause irreversible impairment or even complete functional loss of the affected limb. While surgical reapposition of peripheral nerve results in some axonal regeneration and functional recovery, the clinical outcome in long distance nerve defects is disappointing and research continues to utilize further interventional approaches to optimize functional recovery. In our study, we describe the use of constructs consisting of decellularized vein grafts filled with spider silk fibers as a guiding material to bridge a 6.0 cm tibial nerve defect in adult sheep. We compared allogenic nerve constructs to autologous nerve grafts. The present study was performed to determine if our constructs can integrate and facilitate axonal regeneration, remyelination and node of Ranvier formation.

Material and methods: We transected tibial nerves with a defect of 6.0 cm from adult sheep followed by microsurgical repair by transplantation of vein/spider silk constructs (n=8). 8 months later, nerves were removed and prepared for histology.

Results: The constructs survived and integrated into the repaired nerves. Regenerated nerves were stained for anti-S100β indicating migration of Schwann cells into the construct and neurofilament demonstrating axonal regrowth throughout the 6.0 cm nerve defect. Positive staining for MBP revealed remyelination of regenerated nerve fibers in the constructs. Nodes of Ranvier between Schwann cells in the construct were observed and identified by intense sodium channel (NaV 1.6) staining on the regenerated axons.

Conclusion: Spider silk constructs transplanted at the surgical repair site of transected nerves were able to bridge the lesion site and were associated with regenerated axons. This study demonstrates that spider silk enhances Schwann cell migration, axonal regrowth and remyelination in a long-distance peripheral nerve gap model. This improvement in nerve regeneration could have significant clinical implications for reconstructive nerve surgery.