Vascularized Nano Composite Material PDLLA/PRGD/HAP/VPA Nerve Conduit Repairs Defects Of Sciatic Nerve In Rats

Objective To investigate the effect of n-PDLLA/PRGD/HAP/VPA nerve conduit on the injury of sciatic nerve in rats.Methods 60 adult male SD rats were randomly divided into 4 groups to prepare the right sciatic nerve 1.5cm defect model,with 15 rats in each group.Rats in A group were connected with PDLLA/PRGD/HAP/VPA nerve conduit combining with pHVEGF16 locally injected while those in B group bridged with PDLLA/PRGD/HAP/VPA nerve conduit alone,and C group with autologous nerve transplantation,D group with silicone tube.Sciatic nerve function index was detected every 2 weeks after operation and the general condition of the animals were observed.General observation,electrophysiological examination,gastrocnemius muscle wet weight test,histological observation and transmission electron microscope observation were used to analyze the nerve regeneration in 12th week.Results Sciatic nerve function index showed that the recovery of motor function in the A group was the fastest,followed by the autologous nerve transplantation group,once again for the B group,the recovery of the slowest for the silicone tube group.General situation:group A happened plantar ulcer and gangrene in 2 rats,with the same situation happened in 5 rats in B group,4 rats in C group,6 rats in D group.Electrophysiological results:there was no significant difference in sciatic nerve conduction velocity between A and C group(P>0.05)after 12 weeks of operation,but the A group was better than B and D group,the difference was statistically significant(P<0.05).Gastrocnemius muscle wet weight:A group was significantly better than B and D group(P<0.05),A group and C group was not statistically significant(P>0.05).Histology and transmission electron microscope observation:at 12 weeks after operation,a group,the regenerated nerve fibers were arranged in dense,regeneration nerve fibers mature and become close to normal nerve tissue,visible minority freshmen childish have myelinated nerve fibers,under electron microscope,a large number of mature regenerated nerve fibers,individually visible demyelination,vacuolar changes in schwann cell were uncommon,axon counts were significantly higher than those in B and D group(P<0.05),there is no significant difference between A and C group.Conclusion The use of n-HAP/PRGD/PDLLA/VPA composite materials nerve catheters with local injection of vascular endothelial growth factor gene(pHVEGF16)in treatment of rat sciatic nerve defect showed good restoration effect and indicated better effect of the composite material nerve catheter for nerve regeneration and angiogenesis significantly.