| It was an attractive idea to use absorbable macromolecule nerve conduits to repair peripheral nerve gaps. There were many advantanges with nerve conduits to repairing nerve gaps. First neurotrophic factors could be concentrated within nerve conduits. Second fibre-bridge to anastomose two parts of nerve gaps could be formed ecxactly. Third operation of nerve conduits could be transplanted easily. Two factors were related to the effect of repair peripheral nerve injury with nerve conduits. one were category, physical and chemical character of materials. Another were microenvironment in nerve conduits ,which include fluid, extracellular matrix(ECM) and cells. Research of microenvironment werefocused on the neurotrophic factors (NTFs). Many studies have been done to use nerve conduits filled with exogenetic NTFs with the intention of promote axonal regeneration to the greatest extent efficiently. However concentration of exogenetic NTFs and the means of releasing NTFs still need to be studied. Meanwhile the types and volume of NTFs are most beneficial to peripheral nerve regeneration still need further investigation. Schwann cells are structural and functional cells of peripheral nerve, which can excrete all kinds of NTFs and generate ECM and cellular adhesion molecules. Several lines of investigation have confirmed the marked effects of Shwann cells on promote peripheral nerve regeneration. According to our early research, polyester-polycarbonate nerve conduits made by Zheijang University Macromolecule Institution and us had good permeability, compatibility and degradate time. The conduits could promote peripheral nerve regeneration and functional repair, but the quality of regenerate nerve was still inferior to normal nerve. It is possible theoretically that polyester-polycarbonate nerve conduits filled with Schwann cells cultured in vitro can improve effects of repairing nerve gaps. So we design this experiment that use polyester-polycarbonate nerve conduits filled with Schwann cells to repair nerve gaps in order to define the effects of this conduits. ObjectiveTo evaluate effects of polyester-polycarbonate nerve conduits filled with Schwann cells on repairing sciatic nerve gaps of rats. Materials and MethodsUsing the method of predegeneration to cluture Schwann cell and identified through immoumocytochemical stain. Forty - five adult SD rats were divided into three groups randomly, with 15 in each group. A gap of 10mm~12mm of right sciatic nerve was removed and then bridged with polyester-polycarbonate nerve conduits. In group A, nerve conduit was filled with Schwann cells and DMEM culture fluid. In group B, nerve conduit was filled with DMEM culture fluid. In group C, nerve conduit was empty. After operation walk manner of rats was observed at stated intervals time. They were put to death 20 weeks later. Before death they were mensured sciatic function index(SFI). After death, nerve regeneration was observed. Nerve conductive velocity(NCV) and wet weight of tibial muscle(including experimental and normal side) are mensured. Specimens of sciatic nerve were made according to transverse section and vertical section. Regeneration nerve fiber and myelinated axons were observed and takend count of with microscope. Part of Specimens were examined to know status about myelin sheaths by electron microscope. The data of SFI, NCV, wet weight of tibial muscle and nerve fiber were analysed with statistical software SPSS10.0 (statistically significantdifference P<0.05). Results1 Identification of cells Identification of cells in immoumocytochemical stain, body and protuberance of Schwann cells present dark-brown, positive cells is about 90% of the total cells.2 Observation During experimental time, no rats died and improvement of flexing and contractive limb were found after 4 weeks. Nerve conduits have completely collapsed after 20 weeks, The bridge of conduits and nerves had enlarged. There weren't atrophy of top and bottom segment of nerves. There were many increasing vessels and much conglutination ar... |
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