Experimental Study Of Repairing Peripheral Nerve Defects With Chemical Decellularized Allogeneic Nerve Complex SVF Cells

Objective:Peripheral nerve injury is one of the important causes of physical disability.At least 2 million people worldwide suffer from peripheral nerve injury every year,causing serious economic and living burdens.When the nerve defect segment cannot be completed by microsurgical techniques,nerve transplantation becomes one of the methods for treating peripheral nerve injury.Autologous nerve transplantation has certain limitations as a gold standard,so finding suitable peripheral nerve defect repair materials has become a research hotspot.Based on the concept of tissue engineering,seed cells also play an important role in the repair of peripheral nerve injury.In this study,the sciatic nerve extracellular matrix(ECM)was used as a nerve conduit,and stromal vascular fraction(SVF)and adipose-derived stem cells(ADSCs)were used as seed cells to evaluate their effects on nerve cell and rat sciatic nerve injury repair in vivo and in vitro and then evaluate its effectiveness.Methods:The SD rat sciatic nerve was taken and chemically decellularized by sodium dodecyl sulfate(SDS),and the extracellular matrix components retained were physically and chemically evaluated.In vitro,ADSCs and isolated SVF were obtained by culture,and ADSCs were evaluated by flow cytometry and multi-directional differentiation;At the same time,SVF,ADSCs and dorsal root ganglion(DRG)were co-cultured to compare the effects of promoting axon growth in vitro.In vivo,a 15 mm defect model of rat sciatic nerve was established,and SVF and ADSCs were combined with sciatic nerve ECM graft to repair rat sciatic nerve defect.At 6 weeks postoperatively,the distal part of the graft was taken and immunofluorescence staining was performed to observe the remyelination.At 12 weeks postoperatively,gait analysis,sciatic functional index,gastrocnemius muscle wet weight ratio analysis,toluidine blue staining,transmission electron microscopy and Masson staining were used to evaluate the repair effect of bridging materials on rat sciatic nerve defects.Results:Decellularized sciatic nerve grafts have a 3D grid-like structure while retaining a large amount of collagen,laminin and fibronectin components.ADSCs can be induced to differentiate into adipocytes,bone cells and chondrocytes in vitro;at the same time,SVF and ADSCs can promote axon growth in vitro.The sciatic nerve ECM graft combined with SVF and ADSCs were superior to the simple decellularized nerve transplantation group(the control group)by gait analysis,sciatic nerve index,gastrocnemius muscle wet weight ratio analysis,toluidine blue staining,transmission electron microscopy and Masson staining,the difference was statistically significant.Conclusion(s):In this study,the preparation of sciatic nerve ECM graft and combined SVF and ADSCs can effectively promote the growth of peripheral nerve cells in vitro.The in vivo evaluation can effectively promote the repair of peripheral nerve defects in rats,and the therapeutic effect is close to autologous nerve transplantation.