Age changes in cellular interactions among the endplate components (axon, Schwann cells, acetylcholine receptor, synaptic matrix) during reinnervation to the motor endplate

我们已经显示了再生NMJ中的一些年龄相关变化，例如坐骨神经挤压损伤后末端雪旺细胞和乙酰胆碱受体（乙酰胆碱受体，AChRs）区域的持续损伤。本研究旨在解决这些变化与信号机制的关系。制作比目鱼肌冰冻切片，首先标记NMJ上的组成成分（轴突、雪旺细胞、AChR区），免疫组化双标记神经调节蛋白（NRG）、神经调节蛋白受体（erB 2和erB 3）和胶质细胞源性神经营养因子（GDNF）的表达。接下来，由于已知NRG/erbB信号传导与AChR的聚集有关，我们检查了由α-银环蛇毒素标记的AChR区域中的抗肌萎缩蛋白（DYS，突触后细胞骨架蛋白）的表达。术后4-12周，观察NMJ再生情况。在 ...更多信息 幼年动物NRG分布在再生轴突的全长上，直至生长锥或终末。NRG受体的ErB_2和ErB_3分布于突触褶和终末雪旺细胞。术后4周，NRG/erB 2（或erB 3）表达短暂升高。GDNF定位于NMJ的许旺细胞链、突触褶和终末许旺细胞。GDNF的表达随再生的进行而增强，术后8周大量NMJ呈强阳性表达。在老年肌肉中，任何信号相关物质（NRG、erB 2、erB 3和GDNF）都显示出一些异常（延迟表达、弱染色、畸形）。2.在老年动物的受体区域的分布紊乱经常伴随着异常的DYS的表达（弱染色和部分缺乏）。结论1.突触前和突触后区域之间的相互作用对于NMJ的再生或结构特化是重要的，即，恢复生理功能据认为，与年龄相关的异常分布的信号分子在这里报告有关的再生不足的NMJ。2.老年模型是有用的，以研究在NMJ的信号机制的干扰。少

We have already shown some age-related changes in regenerating NMJs, such as persistent damage in the terminal Schwann cell and the acetylcholine receptor (acetylcholine receptors, AChRs) region after sciatic nerve crushing injury. This research aimed at solving the relation of these changes and the signal mechanism. Cryostat sections of the soleus muscle were made, and first, after the composition element (axon, Schwann cell, AChR region) on NMJ was labeled, the expression of signal-related-substances (neuregulin (NRG), NRG receptors (erB2 and erB3) and glial cell line-derived neurotrophic factor (GDNF)) was double labeled by immunohistochemistry. Next, since NRG/erbB signaling is known to be concerned with the aggregation of AChRs, we examined the expression of dystrophin (DYS, postsynaptic cytoskeleton protein) in the AChR region as labeled by alpha-bungarotoxin. Observation was performed at the time when regeneration of NMJ was in progress (4-12 postoperative weeks).Results. In the … More young animals NRG was distributed over the full length of regenerating axons, up to a growth cone or a terminal. ErB2 and erB3 of a NRG receptor were distributed over the synaptic folds and the terminal Schwann cells. Expression of NRG/erB2 (or erB3) became transiently increased at four postoperative week. GDNF was localized in the Schwann cell strands, and synaptic folds and terminal Schwann cells in the NMJ. Expression of GDNF was reinforced as regeneration progressed, and numerous NMJs showed the strong positivity at eight postoperative week. In the aged muscles any signal-related-substance (NRG, erB2, erB3, and GDNF) showed some abnormalities (delayed expression, weak staining, malformation). 2. Derangement in the distribution of a receptor region in aged animals frequently accompanied abnormalities in the expression of DYS (weak staining and partial lack). Conclusion. 1. The interaction between the presynaptic and postsynaptic region is important for regeneration or structural specialization of the NMJ, i.e., for recovery of a physiological function. It is thought that age-related abnormalities in the distribution of signal molecules reported here relate to the insufficiency of regeneration at the NMJs. 2. The old-age-model is useful in order to study the disturbance of the signal mechanism at NMJs. Less