The Basement Membrane Of Femoral Nerve Branches Repair Sciatic Nerve Defect In Rats

Objective: With the rapid development of social economy,the incidence of peripheral nerve injury is also increasing year by year,which has adversely affected the quality of life of patients and the harmonious development of society.In addition to small nerve defects that can be sutured,autologous nerve transplantation is still the gold standard in the treatment of clinical long-distance nerve defects,but it has many problems,such as limited source and secondary damage in the donor area.Allogeneic decellularized nerve grafts for repairing peripheral nerve defects have been used clinically and have achieved good results.The basement membrane(BM)is the main component of the decellularized nerve,however,whether there are differences of BM in different types of decellularized nerve grafts is unknown,and no relevant researches have been reported.This study explored the difference between the femoral cutaneous branch and the muscular branch basement tube in rats,and observed whether the acellular nerve graft had different effects in repairing the sciatic nerve defect in rats,which could provide some reference for the selection of different kinds of nerve grafts and 3D printing of tissue engineered nerves in clinic.Methods:(1)The cutaneous branches and muscular branches of fresh femoral nerves of healthy 8-week-old male Sprague-Dawley rats were used to detect the expression of structure protein in femoral cutaneous branch and muscular branch by QAR-CAA-67 antibody protein chip technique,and the differentially expressed proteins were obtained;At the same time,its ultrastructural and histological staining were observed.(2)The femoral nerve and its branches of SD rats were taken for chemical decellularization,and then its ultrastructure,histology and Raman spectroscopy were evaluated.(3)In vivo,acellular femoral nerve cutaneous branch grafts(CBG)and acellular femoral nerve muscular branch grafts(MBG)combined with chitosan conduits were to build the tissue engineered nerve grafts that used to repair rat sciatic nerve defects(10 mm).The experimental animals were randomly divided into 4 groups(n=10),CBG(CBG group),MBG(MBG group),Hollow chitosan conduit(HCC group)and autologous nerve grafts(ANG group)were implanted respectively to repair the defect.Postoperative gait analysis,morphology and histology were used to evaluate the effect of repairing rat sciatic nerve defects.Results: In the thickness of myelin sheath and basement membrane canal(28-37 nm),the muscular branch of femoral nerve was larger than the cutaneous branch.The proportion of the positive part of the acetylcholinesterase staining of the femoral nerve muscular branch was larger,while the proportion of the negative part of the cutaneous branch was larger.Gene ontology(GO)enrichment analysis showed that extracellular space was highly enriched of cellular components,and more related genes were up-regulated in the muscular branches of femoral nerve.12 weeks after operation,the results of gait analysis,wet weight recovery rate of gastrocnemius muscle and pathological observation in CBG,MBG and ANG groups were better than those in HCC group,but the results were similar between the CBG group and the MBG group.There is no significance between two groups,but the results of the two groups were slightly worse than the ANG group,and there were statistical significance.Conclusion: Although there are differences in composition and basement membrane structure between sensory nerve(cutaneous branch)and motor nerve(muscle branch)nerve grafts,the repair effect in vivo is similar.When printing nerve grafts in 3D,the thickness of the inner nerve basement membrane tube(28-37 nm)and three-dimensional spatial orientation structure must be taken into account.