Rat’s Sciatic Nerve With Tetramethylpyrazine Pretreatment Promote Neural Regeneration After Allograft

Objective:To investigate the feasibility of sciatic nerve with tetramethylpyrazine pretreatment repair nerve defect on rat.To solve the problem of the nerve allograft liveness is not high in the process.Methods:Wistar rats and SD rats were selected as donors and recipients, respectively (3 months,SPF male rat,200±20g),the sciatic nerve segments of 15mm were harvested from the donors, then randomly preprocessed in 4℃ tetramethylpyrazine solution (0,50,100,200 mg/L, A, B, C, D group,n=16) for six weeks, the ultrastructure of sciatic nerve was observed by transmission electron microscope, Calcein-AM staining was used to observe the change of fluorescence intensity with laser scan confocal microscope(Laser scanning confocal microscope, LSCM). The recipients were randomly divided into A’, B’, C’, D’ group(n=11, corresponding to A, B, C, D group),10mm defect of recipient’s sciatic nerve was repaired by the nerve preprocessed for 6 weeks.One week after the operation, HE staining was used to observe the shift of inflammatory cell in allografts.The gross appearance and sciatic nerve function index(SFI) were detected at different period after the surgery, the electrophysiological changes, regenerated nerve image analysis and transmission electron microscope were performed at 20 weeks post-transplantation.Results:The sciatic nerve in rats pretreated for 6 weeks with 4℃, there were severe demyelination and neuraxis denaturation in group A, while these changes in groups B,C and D were mild, the fluorescence intensity in groups B,C and D were higher than that in group A, and group B was higher than that of group C and D(P<0.05), there was no significant difference in group C and group D(P>0.05). All rates survived to the end of the experiment,one week after the surgery,the observation of Light microscopy showed that the inflammatory cellsin filtrating of allografts in group B’, C’, D’significantly was significantly lighter than that of group A’.After 20 weeks, The SFI, electrophysiological detection, number of myelinated nerve fibers and thickness of myelin were observed at at different times post-transplantation,there were. significant differences between groups B’,C, D’and group A’, group B’and groups C’, D’(P< 0.05),and there were no significant differences between group C and group D’(P> 0.05). The observation of transmission electron microscopy showed that myelinated nerve fibers and thickness of myelin sheath in group A’ was thinner than that in groups B’,C’,D’, and that the hyperplasia of connective tissues in group A’ was more serious than that in groups B’,C’,D’.Conclusion:A certain concentration of Tetramethylpyrazine plays a protective role on sciatic nerve pretreatment, and can promote the nerve regeneration after allogeneic transplantation.