Armstrong R, Toews A D, Morell P
Biological Sciences Research Center, University of North Carolina, Chapel Hill 27514.
J Neurosci. 1987 Dec;7(12):4044-53. doi: 10.1523/JNEUROSCI.07-12-04044.1987.
Focal demyelination was produced in rat sciatic nerve by unilateral intraneural injection of anti-galactocerebroside serum. A functional lesion was confirmed by the presence of nerve conduction block. Histologically, this corresponded to demyelination of 50-70% of the fibers in nerve cross sections; axonal structures appeared intact. At the time of maximal demyelination (7 d), 35S-methionine or 3H-fucose was injected bilaterally into the spinal cord ventral horn. At later times (5 hr-7 d), the sciatic nerve was removed and radioactivity in successive nerve segments was quantitated. The transport rates (approximately 260 mm/d) and the composition of transported proteins and glycoproteins (separated on 7-15% polyacrylamide gradient gels) were not altered in lesioned nerves relative to contralateral control nerves. Light microscopic autoradiographic analysis revealed a similar localization of axonally transported and deposited glycoproteins in demyelinated and control fibers. Initially (8 hr), the majority of label was over axons. Labeled glycoproteins remaining in the nerve after 1 week were retained mainly in axolemmal regions. We conclude that acute focal primary demyelination does not lead to major alterations in the transport or deposition of newly synthesized macromolecules.
通过向大鼠坐骨神经单侧神经内注射抗半乳糖脑苷脂血清产生局灶性脱髓鞘。神经传导阻滞的存在证实了功能性损伤。从组织学上看，这对应于神经横切面上50 - 70%的纤维脱髓鞘；轴突结构看起来完整。在最大脱髓鞘时（7天），将35S - 蛋氨酸或3H - 岩藻糖双侧注入脊髓腹角。在随后的时间（5小时 - 7天），取出坐骨神经并对连续神经节段中的放射性进行定量。相对于对侧对照神经，损伤神经中的运输速率（约260毫米/天）以及运输的蛋白质和糖蛋白的组成（在7 - 15%聚丙烯酰胺梯度凝胶上分离）没有改变。光学显微镜放射自显影分析显示，在脱髓鞘纤维和对照纤维中，轴突运输和沉积的糖蛋白具有相似的定位。最初（8小时），大部分标记物位于轴突上。1周后留在神经中的标记糖蛋白主要保留在轴膜区域。我们得出结论，急性局灶性原发性脱髓鞘不会导致新合成大分子的运输或沉积发生重大改变。
