Study On Using The Tissue Engineered Nerve With Schwann Cells Harvested By The Modified Method To Repair The Peripheral Nerve Defect In Mice

Objective: To explore a new method for in vitro pre-denaturation of peripheral nerves so as to harvest a large number of highly efficient Schwann cells in a short term,and to observe the effect of tissue engineered nerves on the regeneration of sciatic nerve defects.Methods: A mouse model of 5-mm sciatic nerve defect was constructed.Bone marrow-derived cells(BMDCs)of C57BL/6 mice were co-cultured with sciatic nerves in vitro as the experimental group(A group).Sciatic nerves alone were incubated without BMDCs in vitro as the control group(B group).7 days later,samples received general observation.After nerve denaturation,Schwann cells were cultured by enzymatic digestion.Schwann cells in both groups were prepared into 1×10 /ml.Tissue engineered nerves with poly(lactic acid)(PLA)tube,extracellular matrix and Schwann cells were constructed to repair sciatic nerve defects and to establish mouse models in A and B groups.Simultaneously,we set the control group(C group;tissue engineered nerves with PLA tube without Schwann cells for the repair of sciatic nerve defects)and the autologous nerve transplantation group(D group).At 12 weeks after model establishment,nerve conduction velocity and wet weight of triceps surae were calculated and tissue biopsy was conducted.Results: Nerve segments became thicker in a group than in B group at 7 days after culture.At 48 hours after enzymatic digestion,the number and purity of cells were higher in a group than in B group under inverted phase contrast microscope and fluorescence microscope.At 12 weeks after model establishment,nerve conduction velocity was faster,and the recovery rate of wet weight of triceps surae was higher in A group than in B and C groups(P < 0.01),and similar to that in D group.Under the light microscope and electron microscope,the number of nerve fibers was more and myelin sheath was thicker at the distal 1/3 segment of the regenerated nerves in A and D group compared with B and C groups.Conclusions: 1.The pre-denaturation of peripheral nerves with BMDCs in vitro could obtain a large number of highly efficient Schwann cells in a short term.2.Tissue engineered nerves formed by Schwann cells obtained in this way had better effect on regeneration of sciatic nerve defects.3.In this experiment,the tissue engineering neuroclinical application of compound schwann cells was used to treat peripheral nerve injury regeneration and repair,which provided the basis for animal experiment.