The Experimental Study Of The Effect Of Fresh Amniotic Membrane To Nerve Injury And Repair

Objective: The injury of peripheral nerve which is a common clinical disabling disease directly reduces the ability of labor. And it is a heavy burden to family life and society. The repair of the injury the peripheral nerves is affected by many factors and the main factors are the micro environment at neural incision and the local scarring. For this purpose, improving the local micro environment and preventing treatment from the local scarring are the effective means in the treatment of the injury the peripheral nerves. Amniotic membrane which is a semi permeable ensure that the nutrient smooth through and the axons grow, and promote the proliferation of Schwann cells. In addition, the amniotic membrane can inhibit the biological activity of the surrounding fibroblast and the formation of the surrounding scar. Besides, it can limit that the peripheral nerves attack the stump of nerve and the nerve adjoin, so on and so forth.Construct the model of sciatic nerve injury in rats and the nerve is connected under microscope which is packaged by fresh human amnion at neural incision. The effects were evaluated by anatomical observation, light and electron microscope observation, SFI and electrophysiological assessment. Evaluate the effect that the repair of the injury the peripheral nerves is promoted by fresh amniotic membrane.Method: Sixty healthy rats(220-250g) were randomly divided into 3 groups after constructing the model of sciatic nerve injury on one side leg of the rats. In group A, the nerve is wrapped by fresh human amnion at neural incision after the repair of nerve. In group B, A, the nerve is wrapped by biological membrane at neural incision after the repair of nerve. In group C, the blank test. 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: Gross observation:(1) In three groups of rats after opermion incision occullred 7 days after infection, incisionsuture removal, a healing period.(2) Weeks after operation of lower limb slightly swollen, activity was significantly reduced and claudication, spirit is bad, eat less, 2 weeks after the mental status and diet restored gradually. The claudication time of rats in A and B group was shorter than that of group C, and the amount of activity recovery earlier.(3) The rats in A and B group have smaller size and shorter recovery time than the rats in C group in the skin ulcer of foot and toe.(4) After 2 weeks amniotic membrane of people and biological membrane localized slightly absorption, 4week of absorption, 8 weeks completely absorbed.(5) Group A and group B allograft nerve and surrounding tissue adhesion and adhesion slightly loose, group C allograft nerve and surrounding tissue of extensive and close adhesion, blunt and not easy to separate.Light microscopic observation: after 2, 4, 8, 12 weeks in the A group and group B were higher than that of group C nerve recovery. After 4 weeks the regeneration of nerve fibers were not obvious and Lamellar structures are not clear in three groups after 8,12 weeks, The rats in A and B group have more number of regenerated nerve fibers and clear Lamellar structures than the rats in C group. And the rats in A and B group have more thick myelin sheath and greater Axon diameter than the rats in C group. Immunohistochemical technique: The expression of S-100 protein in A, B group was better than that of group C. Axon image analysis: A, B group was better than that of group C about myelinated nerve fiber diameter, the thickness of myelin sheath and number of regenerated nerve fibers. There was a significant difference by statistical analysis(P<0.05). The electrophysiological examination: after 8weeks of neural electrophysiological testing results showed that, in A, B group than in C group. Long incubation period, slow nerve conduction velocities, low amplitude, has statistically significant difference(P<0.05). The sciatic function index: A, B group sciatic nerve function in recovery rate was higher than that in group C, has statistically significant difference(P<0.05).Conclusion: It can ease the adhesion which is between the damaged nerve and surrounding tissues, and it can prevent scarring. It promotes the regeneration of nerve fibers, the increases of axon diameter and the thickening of myelin sheath. It can ease the inflammatory response and the immune response at neural incision.