| Peripheral nerve injury is a frequently occurring disease in clinicalpractice and tumor is a common cause. Direct suture of the defect often lead toformation of nerve pseudotumor that would affect the recovery of neurologicalfunction, especially when the lesion is more than10mm wide it’s actuallyimpossible to do the suture. Auto-graft is a useful alternative, but may causeneurological symptoms in the transplanted area, and the graft can hardlyachieve the desired recovery state. In short, the clinical treatment of nervedefects is fairly difficult currently. As the lifestyle become more fast-paceddue to widely used transportation, rate of peripheral nerve injury is increasingyear by year, and this seriously impacts the quality of people’s lives and work.Therefore, the clinical treatment of medium-long segment peripheral nerveinjury has become an important issue in the field of neural transplantationresearch. In recent years, with the rapid development of biomedicine, thenerve conduit, particularly, bio-degradable conduit has become a leader in thefield of neural transplantation, consolidating the basis of clinical neuraltransplantation. However, the high price and unavoidable rejection make itdifficult for the wide application of it in clinical practice. Crab membrane (i.e.a layer of tough, transparent membrane in the crab pincers, referred to as crabmembrane) is a bio-originated degradable material. In this project, weestablished a rat model of peripheral nerve sheath tumor, transplanted crabmembrane to the rats’ sciatic nerve defects (≥10mm), and observed theimprovement of peripheral nerve repair, providing a solid foundation andtheoretical basis for further studies. Objective:The repair function of crab membrane for nerve defects was investigatedby observing nerve regeneration and functional recovery of the10mm sciaticnerve defect due to nerve sheath tumors, and detailed data was gathered forsubsequent studies.Methods:1Preparation of nerve sheath tumor model:16clean grade SD rats wereselected as subjects, their right sciatic nerve were transected and then suturedend to end.4weeks later, the nerve sheath tumor model is formed. All ratswere then randomly distributed into test group A that would receive crabmembrane repair and negative control group B.2Preparation of crab membrane:10crabs with big pincers were selected.The transparent membrane in the pincers was soaked with normal saline toremove the impurities. Then the membrane was placed in sterile EP tubes andfreezed for72h in an ultra-low-80°C refrigerator to remove the antigencomponents. At last, after rewarming at room temperature for48h, it’s readyfor use.3For both groups, the sheath tumors were first resected(Nerve defect toachieve10mm). Then, the defect ends was bridged with crab membrane forgroup A while both ends were directly sutured to adjacent abdominal wall forgroup B. Nerve growth and functional recovery and some other conditionswere observed.4General situation was observed throughout the experiment, usingfootprints measurement method of sciatic nerve indexes were measured in30minutes minutes and2,4,6,8,10,12weeks after surgery, nerve growthconditions were observed4,8,12weeks after surgery under a electronicmicroscope and electrophysiological test were perform12weeks after surgery.Results were compared between the two groups.Results:1General observation:Observed within30minutes after surgery, all rats drooped their right foot,their toes close together, and they drag their body when they walk. No retraction movements or claw-spread reflex were observed when the rats wereacupunctured at the right toe.3weeks after surgery, refractory movements andclaw-spread reflect can be observed;6-10weeks later, most of the rats’retraction movements and claw-spread reflect became sensitive;11weeks later,all8rats of group A showed agile response to acupuncture and normal activity;and till12weeks after surgery,2rats of group B showed agile response andnormal activity,3were less sensitive, and the other3were still refractory.2Under-scope observation:4weeks after surgery, both group A and group B showed surroundingtissues adhesion, and it’s more severe in group A than in group B.8weeksafter surgery, the tissue adhesion in group A become less severe than in groupB; for group A, regeneration of nerve fibers and remote connection can beseen when cut open, and absorption of the crab membrane can be detected.12weeks later, nerve fibers grow into the remote ends; for group A, the crabmembrane is completely absorbed, no obvious tissue adherent can be seen,and nerve continuity is fairly good; as for group B, some pseudotumor formedwhich impeded nerve regeneration. Nerve regeneration of group A is betterthan that of group B.3Sci-atic functional index:Sci-atic functional index measured within30minutes after surgery,2,4,6,8,10,12weeks after surgery, and comparison was performed between thetwo groups: at2,4weeks, no significant difference was observed; but at6,8,10,12weeks and especially12weeks the results were distinct, the recovery ofgroup A is significantly accelerated.4Electrophysiology and regenerative morphology:12weeks after surgery, electrophysiology and regenerative morphologywas compared between the two groups: the conduction velocity, maximumamplitude, myelinated axon diameter, myelin thickness and fiber density ofgroup A were all significantly higher than those of group B (P<0.01).Conclusions:Crab membrane can significantly promote the nerve regeneration and functional recovery after the10mm sciatic nerve damage due to nerve sheathtumors. |
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