Willison H J, Trapp B D, Bacher J D, Quarles R H
Developmental and Metabolic Neurology Branch, NINCDS, Bethesda, MD 20892.
Brain Res. 1988 Mar 15;444(1):10-6. doi: 10.1016/0006-8993(88)90907-9.
A model of peripheral nerve regeneration in the cat in which freshly severed proximal axons penetrate a permanently transected distal stump, composed of quiescent Schwann cells has been used to study the pattern of myelin protein expression during myelination associated with axonal regeneration. The expression of the myelin-associated glycoprotein (MAG) and the compact myelin proteins P0 and P1 has been analyzed by immunoassays at sequential distances down the regenerating nerve. In the most proximal regenerating zone of this model, MAG is expressed at a significantly higher level (7.9% of normal) than P0 (2.3% of normal) or P1 (1.7% of normal). In addition, elevated levels of MAG are sustained farther into the distal stump than those of P0 and P1. These results are similar to the pattern of accumulation of myelin proteins seen during normal feline development and indicate that MAG, which is localized in part to the periaxonal Schwann cell membranes, may play an important role in the early events of establishing and maintaining the relationship between Schwann cell and axon. Neither MAG, nor P0, were detected in non-myelinating Schwann cells in the distal stump, although it is possible that they are present at levels below the detection threshold of the assays, which are approximately 0.1% of normal.
在猫的外周神经再生模型中，新鲜切断的近端轴突穿透由静止的施万细胞组成的永久性横断远端残端，已被用于研究与轴突再生相关的髓鞘形成过程中髓鞘蛋白表达的模式。通过免疫测定法分析了再生神经沿线不同距离处髓鞘相关糖蛋白（MAG）以及紧密髓鞘蛋白P0和P1的表达。在该模型的最近端再生区域，MAG的表达水平（为正常水平的7.9%）显著高于P0（为正常水平的2.3%）或P1（为正常水平的1.7%）。此外，MAG水平升高在远端残端持续的距离比P0和P1更远。这些结果与正常猫发育过程中所见的髓鞘蛋白积累模式相似，表明部分定位于轴突周围施万细胞膜的MAG可能在建立和维持施万细胞与轴突之间关系的早期事件中起重要作用。在远端残端的无髓鞘施万细胞中未检测到MAG和P0，尽管它们有可能以低于检测阈值（约为正常水平的0.1%）的水平存在。
