Regeneration of facial nerve defects with xenogeneic acellular nerve grafts in a rat model.

BACKGROUND Because of ease of harvest and low immunogenicity, xenogeneic acellular nerve graft (XANG) may be an alternative to autologous nerve to repair facial nerve defects. METHODS Facial nerve defects of Wistar rats were repaired by XANG, and nerve gap regeneration was investigated by electrophysiological test, horseradish peroxidase (HRP) retrograde tracing and histomorphometric analysis, as compared to autograft. RESULTS Twenty weeks after the grafting, electrophysiology showed that whisker pad muscles responded to the electrical stimuli given at the site proximal to the transplantation in 2 groups. Some HRP-labeled facial motorneurons were located on the facial nucleus of the operated side, and an abundance of myelinated axons were found at the middle of the grafts and obvious motor endplates in the target muscles in 2 groups, although they were inferior to the contralateral side in numbers. CONCLUSION XANG represents an alternative approach for the reconstruction of peripheral facial nerve defects.