Application Of New Peptide Hydrogel Repair Of Traumatic Peripheral Nerve Defect In Experimental Research

Objective: The incidence of peripheral nerve injury is very high in the world,in which the peripheral nerve defect of the nerve fiber has seriously affected the quality of life of the patients,and the peripheral nerve injury has become the focus of the world.Although the microsurgical technique has made remarkable progress,the autologous nerve transplantation as the gold standard for clinical treatment of peripheral nerve defects still has many limitations.such as limited sources of donor nerve and Limited donor.Therefore,the search for new peripheral nerve defect repair material becomes a research hotspot.This study used peptides hydrogels to repair the defect of sciatic nerve in rats and evaluated its effectiveness.Methods: The prepared polypeptide hydrogel(The material is provided by T-singhua university materials institute)was transplanted into the chitosan catheter,and the polypeptide hydrogel compound chitosan catheter was constructed.We inoculated the schwann cells and the dorsal root ganglion in the polypeptide hydrogel,and observed the number and the tendency of growth in vitro.In vivo,we established a model of 10 mm long defect of sciatic nerve(n=60),dividing them into five groups randomly(n=12)and chitosan conduit only(CCO),IKVAV peptide hydrogel(IKVAV),RGI peptide hydrogel(RGI),RGI+IKVAV peptide hydrogel(RGI+IKVAV)and autologous nerve grafts(ANG),respectively.After 12 weeks,we evaluate the effect of four bridging materials on repairing sciatic nerve defects in rat by through gait analysis,neural electrophysiology(NEP),sciatic nerve functional index(SFI),recovery rate of gastrocnemius muscle wet weight and histopathology methods such as immunofluorescence staining,toluidine blue staining and transmission electron microscope observation.Result: RGI+IKVAV peptide hydrogels can significantly promote thenumber of SCs and secrete myelin proteins and accelerate the growth of DRG axons,which are better than IKVAV and RGI peptide hydrogels.At 12 weeks after transplantation,the results of gait analysis,SFI,NEP,recovery ratio of muscle wet weight and histopathology inRGI+IKVAV peptide hydrogels,IKVAV peptide hydrogel group,RGI peptide hydrogel and ANG group RGI+IKVAV peptide hydrogels group,IKVAV peptide hydrogel group,RGI polypeptide hydrogel group and ANG group are all obviously superior to CCO group..However,there was no significant difference between IKVAV polypeptide hydrogel group and RGI polypeptide hydrogel group.Conclusion: The new polypeptides hydrogel plant of RADA/IKVAV+RGI has excellent biocompatibility and can effectively repair the peripheral nerve defects in rats,and its therapeutic effect is close to autologous nerve transplantation.