Enhancing Functional Recovery after Segmental Nerve Defect using Nerve Allograft treated with Plasma-Derived Exosome.

BACKGROUND: Nerve injuries can result in detrimental functional outcomes. Currently, autologous nerve graft offers the best outcome for segmental peripheral nerve injury. Allografts are alternatives, but do not have comparable results. This study evaluated if plasma-derived exosome can improve nerve regeneration and functional recovery when combined with decellularized nerve allografts.

METHODS: The effect of exosomes on Schwann cell proliferation and migration were evaluated. A rat model of sciatic nerve repair was used to evaluate the effect on nerve regeneration and functional recovery. A fibrin sealant was used as the scaffold for exosome. 84 Lewis rats were divided into Autograft, Allograft, and Allograft with exosome groups. Gene expression of nerve regeneration factors were analyzed on postoperative day 7. At 12 and 16 weeks, rats were subjected to maximum isometric tetanic force (ITF) and compound muscle action potential (CMAP). Nerve specimens were then analyzed via histology and immunohistochemistry.

RESULTS: Exosomes were readily taken up by Schwann cells (SCs) that resulted in improved SCs viability and migration. Treated allograft group had comparable functional recovery (CMAP, ITF) as the autograft group. Similar results were observed in gene expression analysis of nerve regenerating factors. Histological analysis showed no statistically significant differences between treated allograft and autograft groups in terms of axonal density, fascicular area, and myelin sheath thickness.

CONCLUSION: Plasma-derived exosome treatment of decellularized nerve allograft may provide comparable clinical outcomes to that of an autograft. This can be a promising strategy in the future as an alternative for segmental peripheral nerve repair.