Phillips D E
Department of Biology, Montana State University, Bozeman 59717.
Exp Neurol. 1989 Jan;103(1):90-100. doi: 10.1016/0014-4886(89)90190-8.
This study was designed to morphologically evaluate the effects of limited postnatal alcohol exposure on the development of myelin and axons in the rat optic nerve. Rat pups were artificially reared on Days 5-18 with a supplemented milk diet fed via a chronic gastrostomy tube. Experimental animals received 4% ethanol in their diet on Days 5-9, otherwise the experimental and control animals received identical diets in identical volumes. Optic nerve tissues were prepared for electron microscopy on Days 10, 16, 22, 29, and 90. The cross-sectional areas of optic nerves were smaller, there were fewer myelinated nerve fibers per unit area, and the progress of myelination was slowed on Day 10 in the ethanol-exposed animals. All of these effects were compensated for at later times. The ratio of myelin thickness to axon diameter was similar in experimental and control animals, indicating that the interaction between axon size and myelin formation was not affected by alcohol. The general distribution of axon sizes was unaffected by ethanol except at 10 days when the largest fibers were smaller. There was no evidence of alcohol-induced degeneration of axons, myelin, or glial structures. Thus, alcohol exposure during myelin development causes a delay in myelin acquisition that is later compensated for.
本研究旨在从形态学角度评估出生后有限期酒精暴露对大鼠视神经髓鞘和轴突发育的影响。在出生后第5至18天，通过慢性胃造瘘管给幼鼠人工饲养补充乳类饮食。实验动物在第5至9天的饮食中摄入4%的乙醇，除此之外，实验动物和对照动物以相同体积摄入相同的饮食。在第10、16、22、29和90天制备视神经组织用于电子显微镜检查。在第10天，乙醇暴露组动物的视神经横截面积较小，每单位面积的有髓神经纤维较少，髓鞘形成进程减缓。所有这些影响在后期都得到了补偿。实验动物和对照动物的髓鞘厚度与轴突直径之比相似，表明轴突大小与髓鞘形成之间的相互作用不受酒精影响。除了在第10天最大的纤维较小外，轴突大小的总体分布不受乙醇影响。没有证据表明酒精会导致轴突、髓鞘或神经胶质结构变性。因此，在髓鞘发育期间暴露于酒精会导致髓鞘形成延迟，但后期会得到补偿。
