| Objcetive: Peripheral nerve injury(PNI)is a common clinical disabling disease.Up to now,the repair of peripheral nerve injury has been a hotspot and a difficult problem for scholars.Though various methods have been tried,no adequate treatment exists and none is routinely used in the clinical practice.Human amniotic membrane(HAM)is a thin film on the inner surface of the amniotic cavity,which is easy to get.It can replace the damaged nerve cells and repair the damaged nerves.HAM can also secrete neurotrophic factors,improve microenvironment and promote nerve regeneration.Meanwhile HAM inhibits the inflammatory response and reduces the production of granulation and scar tissue.The amnion does not cause T-cell-mediated specific rejection.In this experiment,SD rat sciatic nerve clamp model was used to observe the injury and repair process of rat sciatic nerve periodically.Amniotic membrane was used to wrap the injured sciatic nerve to observe the effect of amniotic membrane on nerve repair and regeneration.Method:Ninetyty healthy rats(150-200g)were randomly allocated into 3groups: group A(nerve wrapped with amniotic membrane),group B(nerve wrapped with chitosan gel),group C(do nothing).The effects were evaluated by anatomical observation,light and electron microscope observation,SFI,electrophysiological assessment,axon imaging analysis,action potential,the function index of sciatic nerve and its recovery rate.Results:1.General observation: compared with the blank group,the mild postoperative limb swelling,neurohyperemia,and edema were obserbed.In addition,the conglutination with the surrounding tissue was mild in amniotic group.2.Light microscope observation: the inflammatory reaction was mild inthe amniotic group.There were few fibroblasts and newborn capillaries.3.Electron microscope observation: in amniotic group,function of organelles was active.There were few fibroblasts and less collagen.Compared with the blank group,the amniotic group spend less time to repair and regenerate the nerve.4.Immunohistochemistry showed that the more expression of S-100 protein was showed in the amniotic membrane group,indicating that the proliferation of Schwann cells was active.and the expression of S-100 last a long time.5.The axon image analysis showed that there was no significant difference in the number of myelinated fibers in the three groups(P>0.05).The thickness of the myelin sheath and the diameter of the myelinated fibers in the two groups(the amniotic membrane group and the chitosan group)were superior to those of the blank group(P<0.05),indicating that the amniotic membrane group had a high degree of myelinated fiber maturity.6.Neurophysiological stimulation: there was no significant difference on nerve conduction velocity among the three groups(P>0.05).The amplitude was significantly different among the three groups(P<0.05).There was no significant difference between the amniotic membrane group and the chitosan group(P>0.05)in the latent period.There was a statistical significant difference compared with the blank group(P<0.05).7.Sciatic nerve function index: the recovery rate of sciatic nerve in the amniotic membrane group and chitosan group were higher than that in the blank group(P<0.05).Conclusion: HAM can facilitate a relatively stable micro environment for nerve repair,reduce adhesion,inhibit inflammatory reaction,promote the proliferation of Schwann cells,promote the repair and regeneration of nerve,and show better therapeutic effect.The HAM has a long retention time in the body,which is beneficial to the regeneration of the nerve and the maintenance of the microenvironment,and the stimulation of the secretion of S-100,and is beneficial to the regeneration of the nerve and the recovery of the function.Inthis respect,the amniotic membrane is better than the chitosan.This experiment provides theoretical basis and animal experimental foundation for treatment of peripheral nerve injury with use of HAM. |
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