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背景:Wallerian变性时髓鞘溃变碎片的清除对于神经的再生至关重要,但溃变碎片的清除机制一直没有彻底阐明,关于参与清除的细胞成分类型仍有很大争议。目的:探讨大鼠坐骨神经再生过程中许旺氏细胞的自噬作用。设计:完全随机自身对照研究。地点和对象:本实验由第一军医大学解剖教研室、汕头大学医学院中心实验室和西南大学达拉斯医学中心精神病学部共同完成,研究对象为成年Wistar大鼠30只,雌雄各半,体质量180-250g。干预:横切大鼠坐骨神经制作Wallerian变性模型,分别于造模后0,0.5,1,1.5,2,3,4,5,7,10,15d取远断端组织行电镜观察。主要观察指标:电镜观察轴突和髓鞘的超微结构,Gomori染色后检查酸性磷酸酶活性。结果:轴突在第0.5天时从髓鞘脱离,溃变呈空泡状。第2天开始髓鞘皱褶、断裂形成碎片,许旺氏细胞内见大的膜结合髓鞘碎片和许多散在小碎片,并与溶酶体融合形成自噬泡,呈酸性磷酸酶(AcPase)阳性。第4天时内膜区偶见幼稚细胞,1周后见大量幼稚细胞。第7天后许旺氏细胞内自噬泡数量开始减少。实验全程偶见巨噬细胞,内有吞噬泡。结论:大鼠坐骨神经再生过程中溃变髓鞘主要经许旺氏细胞自噬清除,许旺氏细胞脱分化为许旺氏细胞祖细胞后大量增殖分化参与神经再生过程。
BACKGROUND: The removal of myelin sheath fragments during Wallerian degeneration is crucial for nerve regeneration. However, the mechanism of clearance of the ulcer fragments has not been completely elucidated. There is still considerable controversy regarding the types of cellular components involved in clearance. Objective: To investigate the autophagy of Schwann cells in the process of sciatic nerve regeneration in rats. Design: Completely randomized self-controlled study. Location and object: The experiment was completed by the Department of Anatomy, First Military Medical University, Central Laboratory of Shantou University Medical Center and the Department of Psychiatry, Dallas Medical Center, Southwest University. The object of study was 30 adult Wistar rats, male and female, 180- 250g. Intervention: Transverse rat sciatic nerve was made Wallerian degeneration model, respectively, at 0,0.5,1,1.5,2,3,4,5,7,10,15 d after modeling distal far end of the line electron microscopy. MAIN OUTCOME MEASURES: The ultrastructures of axons and myelin sheaths were observed under electron microscope. Acid phosphatase activity was examined after Gomori staining. RESULTS: Axons were detached from the myelin sheath on day 0.5, and were degenerated into vacuoles. On the second day, the myelin folds began to rupture to form fragments, and the large membrane-bound myelin fragments and many scattered small fragments in Schwann cells formed autophagic vacuoles with lysosomes, which showed acid phosphatase (AcPase) Positive. On the fourth day, the immature cells in the endometrium were occasionally seen, and a large number of naive cells were seen after one week. After 7 days, the number of autophagic vacuoles in Schwann cells began to decrease. Occasionally observed macrophages throughout the experiment, there phagocytic bubble. CONCLUSION: The myelin sheath is mainly cleared by Schwann cells during autologous sciatic nerve regeneration. The Schwann cells dedifferentiated into Schwann cells and proliferated and differentiated into neural regeneration process.