| Objective:. To plant fetus rabbit Schwann cells that were cultured and purified in vitro into the extracted nerve graft of homogeneity and made it into bridging complex. Then transplanted the bridging complex into the rabbit defective sciatic nerve. Observed the regeneration and the functional recovery of rabbit sciatic nerves. Accordingly, it could confirm that the bridging complex not only offered favourable supporting effects but also induced and promoted the regeneration of neuraxises and medullary sheathes. Confirmed that the complex neural bridge without antigen or small .This method would provide experimental basis for the repairing of defect of peripheral nerve.Methods: 1. Preparation of the Schwann cell cultures: Executed the adopted pregnancy New Zealand white rabbit and taken out the fetus rabbits of 28 days conceptus age. Under operation microscope, both sides of sciatic nerves were achieved and the external connective tissue of the nerve segments was stripped, and then the segments were scissored up to shreds. We applied enzyme digestion (trypsin / collagenase) to culture Scs. In order to remove fibroblast, the double 30min differential adhesion was applied. We even added NGF to FBS to promote SCs growing. Observed SCs under the microscope and made them go down to posterity. Collected and counted the good growth cells of the second filial generation. Accredited them with S-100. 2. Preparation of Extracted Nerve Grafts (eNG): Two sides of the adult New Zealand white rabbit sciatic nerves were used to prepare the eNG. Before the extraction, sheared the adipose tissue and part of the epineurium with the operating microscope. Divided them into 3cm one section. Then they were dipped in 4oC distilled water immediately, Soaked for 6hs. After that, immerged them into 3% Triton X-100 solution. 12hs later, the sciatic nerves would be put into 4oC distilled water again for another 6hs. Then they would be treated by 3% Triton X-100 for the second 12hs. The process would not stop until the sciatic nerves were treated by 3% Triton X-100 totally for 96hs. The eNG were examined with paraffin section stained in Hematoxylin-Eosin .The other piece of nerve was observed with scanning electron microscope. 3.Preoperative from the experimental group of 18 healthy adult New Zealand white rabbits blood T-lymphocyte subsets and IL-2 for testing. 4.The experimental study of populating Schwann Cells into the extracted nerve graft of homogeneity in repairing of rabbit sciatic nerve: Cell suspension containing about 108/ml of SCs were micro-injected in the extracted nerve graft by a stainless needle, glass-cylinder 100ul microsyringe. And then transplanted it into the rabbit defective sciatic nerve quickly(experiment group).The control group did not transplant Schwann cells. Observed the ulcers on the feet of the rabbit 4, 8 and 12 weeks after operation. Detected the regeneration of neuraxises, motor end plate and medullary sheathes of rabbit sciatic nerves by EMG light microscope and electron microscope and so on .Then analyzed them in statistics.5.After 5 and on the 12th for rabbit blood IL-2 detection and T-lymphocyte subsets detection and statistical analysis: t-test.6. Tectology espial:observe the growth of Schwann cells 5 days after operation.7.Observe their psychosis,bite and sup,and cicatrisation after operationResults: All rabbits′s mental state and meatand drink very good.They were lame and there was no infection in cuts.Schwann cells interconnected and aligned in microtubulein reactivate nerve fiber and they formed cell-chain like Büngner's band. The experimental study of populating Schwann Cells into the extracted nerve graft of homogeneity in repairing of rabbit sciatic nerve: 4,8 and 16 weeks after operation. The experimental group was better than the control group in healing of ulcers,the number of nerve fibres,the ultramicrostructure of medullary sheaths ,the regeneration nerve , the structure of the motor end plate and muscle. Before and after transplant proleulzin , CD4~+ and CD8+T lymph-cell′s ratio in peripheral blood had no change,and CD4~+/CD8~+ also had no change. Conclusions: 1. It could confirm that the bridging complex just only offered favourable supporting effects but also induced and promoted the regeneration of neuraxises and medullary sheathes.The acellular nerve allografts transplanted with SCs could significantly promote the reconstruction of the nerve-muscle structure and functional recovery of injured sciatic nerve.2.The compound nerve maded by fetus rabbit Schwann into acellular nerve allograft has all-right histocompatibility and has no rejection in host and didn't cause general immune reaction. So the compound nerve maded by fetus rabbit Schwann cells into acellular nerve allograft is possible to become an ideal tissue engineered nerve.
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