Animal Experiment Study On Repairing Peripheral Nerve Defects With BBC Combined With Exosomes

Objective: The nerve injury caused by trauma brings great burden to social economy and mental pressure to family.Peripheral nerve injuries accounted for about2.8 % of all injuries.Although peripheral nerves have the ability to repair themselves,it is difficult to achieve complete functional recovery,especially for long nerve injuries and proximal nerve defects.At present,there are many clinical treatments for peripheral nerve injury,but the functional recovery effect is not ideal,and the repairing materials are expensive and risky.Therefore,this study intends to use BC membranes combined with Mscs-derived Exosomes(EXO)to repair sciatic nerve defects in rats,so as to explore new materials and strategies for peripheral nerve defects.Methods :(1)The right sciatic nerve long segment nerve defect model of SD rats was established,36 adult rats of SPF 3 weeks old were randomly divided into 6groups: group A: nerve auto graft group,group B: EXO injected via gastrocnemius muscle after autogenous nerve bridge group,group C: BBC soak EXO group,group D: EXO injected via gastrocnemius after BBC bridge group,group E: BBC group,group F: fascia group.Postoperative B and D groups were injected with EXOs via gastrocnemius.(2)The rats’ footprints were analyzed at 4 and 8 weeks after establish animal model and the Sciatic Nerve function index(SFI)was calculated.A hot plate instrument was used to determine the incubation period of thermal pain.(3)Eight weeks after the establish animal model,the distal portion of the broken sciatic nerve was taken and the semi-thin sections were prepared by immunohistochemistry staining.The number and diameter of the regenerated medullated fibers were calculated by imaging analysis.Results:(1)At 4 weeks and 8 weeks after operation,the motor function and the degree of toe separation of the rats in group A and Group B were significantly better than those in other groups,among which group C was better than group E,while group E was better than group F.(2)To measure the recovery degree of SFI and heat pain incubation period,group A and C were significantly better than group E and F,and the difference was statistically significant(P P<0.05).SFI values at 4 weeks and 8 weeks after surgery were significantly better in group B than in other groups,and the difference was statistically significant(P & LT;0.05),in which Group C was better than group E,and Group E was also better than group F,the difference was statistically significant(P<0.05).(3)The number and diameter of nerve fibers 4weeks and 8 weeks after surgery,group A and Group C were superior to group E,and the difference was statistically significant(P & LT;The number and diameter of nerve fibers in group E at 8 weeks were also better than those in group F(P & LT;0.05).Conclusion: Bridging peripheral nerve defects with BC membrane alone can lead to nerve regeneration,and the effect of promoting peripheral nerve regeneration is not as good as that of BC membrane combined with EXO.(1)BC membrane can guide nerve regeneration,(2)EXO derived from MSC can play an auxiliary role in nerve regeneration.