Preparation And Evaluation Of PLCL/ECM Nerve Conduitconduits With Using Electrospinning Technique

Objective:To prepare a nerve repair conduit containing an extracellular matrix（ECM）by using electrospinning technology and evaluate its function.Methods:Two types of nerve conduits were prepared by electrospinning,namely,a polylactic acid-polycaprolactone（PLCL）conduit formed by electrospinning a 10%PLCL solution,and ECM was added to the 10%PLCL solution,and then The PLCL/ECM conduit formed by electrospinning was examined by scanning electron microscope,staining,mechanical properties,cytotoxicity and cytocompatibility.Then,54 adult male Wistar rats were selected,and the sciatic nerve was severed and bridged with different materials.The distance between the distal and proximal nerves was 8mm.Animal experiments are divided into three groups based on the transplant material.Group A:PLCL/ECM conduit group;Group B:PLCL conduit group;Group C:Rat autologous nerve transplantation group.The behavioral（SFI）,electrophysiological（NCV）,mid-calf circumference,and toluidine blue staining were measured at 4 weeks,8 weeks,and 12 weeks after operation,and the effects of sciatic nerve regeneration were analyzed and evaluated.Results:After the PLCL/ECM conduit was stained with Coomassie brilliant blue,a uniform ECM distribution on the PLCL material was seen under the microscope.The mechanical tensile results of the sutures of the two conduits can be seen.The modulus of elasticity of the PLCL/ECM conduit is greater than that of the PLCL conduit（p<0.05）,but the yield stress of the PLCL/ECM conduit and the yield of the PLCL conduit The difference in stress is not large（p>0.05）,which indicates that the addition of ECM does not have much effect on the mechanical tensile effect of the suture of the nerve conduit.The cytotoxicity test results showed that the OD450 of each concentration group of PLCL and PLCL/ECM was significantly higher than the OD₄₅₀of the positive control group and was not much different from the OD₄₅₀50 of the negative control group under different culture time.It can be found by calculating the cell survival rate of each group,The cell survival rates of the PLCL/ECM and PLCL groups were not significantly different at different concentrations of the extracts at24h（p>0.05）,but the cell survival rates of the PLCL/ECM group were all at 48,72,and 96h after culture.Cell survival rate was higher than that of PLCL group（p<0.05）.Comparing the cell adhesion of the two groups under scanning electron microscopy,it can be seen that the cell adhesion of the PLCL/ECM group is better than that of the PLCL group,which indicates that the PLCL/ECM group is better than cell growth.There were no deaths or incision infections,no significant rejection and other complications related to the operation.After the transplantation,over time,all aspects of functions in group A,B,and C are gradually recovering,group C recovers faster,and groups A and B recover slowly.Indicators at 4 weeks after operation:At 4weeks,the results of behavioral and mid-calf perimeter experiments were not significantly different between the three groups,but the NCV in group C was significantly better than the other two groups（p<0.05）,and myelin axons The number was also significantly greater than the other two groups（p<0.05）.Indexes at8 weeks after operation:（1）Sciatic nerve index:group C is better than group A and group B（p<0.05）,and there is no significant difference between group A and group B（p>0.05）;（2）Electrophysiological test:group C NCV is better than group A Group,but no significant difference（p>0.05）,NCV in group C was higher than group B（p<0.05）,NCV in group A was higher than group B,but there was no significant difference（p>0.05）;（3）Mid-calf perimeter detection:The calf muscle resilience in group C was better than those in groups A and B（p<0.05）,but there was no significant difference between groups A and B（p>0.05）;（4）Toluidine blue staining:Compared with 4 weeks,the myelin fragments in each group decreased and the number of myelinated axons increased significantly in 8 weeks.The number of myelinated axons regenerated in group C was significantly more than that in groups A and B（p<0.05）;the number of myelinated axons in group A was significantly increased and more than that in group B（p<0.05）.Indexes at 12 weeks after operation:（1）Sciatic nerve index:Although group C is still better than group A（p<0.05）,the difference is smaller than that at 8 weeks.Group A is better than group B（p<0.05）;（2）Electrophysiological testing:The NCV in both groups A and B was significantly higher than that at 8 weeks（p<0.05）.Although the NCV in group A was still smaller than that in group C（p<0.05）,the difference was smaller than that at 8 weeks.Difference（p<0.05）;（3）Mid-calf perimeter detection:the muscle recovery rate of each group was improved compared to 8 weeks,and the muscle recovery rate of group C was higher than that of group B（p<0.05）and there was no significant difference between group A（p>0.05）,there is still no significant difference between group A and group B（p>0.05）;（4）Toluidine blue staining:Compared with 8 weeks,the myelin fragments of 12 weeks are basically missing,and the myelin axons of group A The number was significantly increased and better than that of group B（p<0.05）,and was comparable to that of group C（p>0.05）.Conclusion:The addition of acellular matrix not only improves the biocompatibility of nerve ducts,but also promotes the repair of sciatic nerve,and provides new possibilities for the study of repair of peripheral nerve defects.