Effect of Collagen Gel on Sciatic Nerve Regeneration in the Polyvinylidene Fluoride Tube

Background: The limited availability of donor sites for nerve grafting has continued to stimulate research toward finding suitable alternatives for autograft. The aim of this research was to study the effect of piezoelectric channel and collagen gel on nerve regeneration. Materials and methods: This research is an experimental study. Forty eight male rats (200-250 gr) were used. After axotomy, 1cm segment of the sciatic nerve in rats was resected, and the gap was then bridged by one of the four methods (Polyvinylidene fluoride or PVDF + Collagen gel, Autograft, Sham and Control). All animals were evaluated at 7, 21, 35, 46, 60 and 90 days after operation by sensory test, sciatic functional index (SFI) and at 90 days by electrophysiologic testing. Sciatic nerve was studied by light and electron microscope after 4 and 12 weeks of implantation. Findings: At 90 days after operation, there was no difference in sensory testing between groups. The mean SFI at the 9 weeks, in autograft group was superior to that of Collagen gel + PVDF group (P<0.01). Mean motor nerve conduction velocity in the difference between experimental groups was not significant (P=0.05). After 4 weeks of implantation, regenerated tissue cables into PVDF tube were round shaped and the mean number of myelinated axons in Autograft group was superior to that of Collagen gel + PVDF group (P<0.001). Mean number of myelinated axons in Collagen gel + PVDF group were lower than autograft group (P<0.01), after 12 weeks of implantation. Conclusion: The positive effects of collagen gel on regeneration of nerve through a PVDF channel seen in this study suggest that it may by useful for treating peripheral nerve injuries.