Moreno-Flores M T, Olazábal U E, Kreutzberg G W
Max-Planck-Institute of Psychiatry, Department of Neuromorphology, Martinsried, Germany.
Exp Neurol. 1997 Jul;146(1):10-6. doi: 10.1006/exnr.1997.6526.
Nerve injuries lead to metabolic and morphological changes in the cell bodies of the neurons of origin. Increases in glucose turnover in axotomized facial and hypoglossal motor nuclei have been described. Glucose-regulated protein 78 kDa (GRP78) is implicated in cellular protein folding and subunit assembly and responds to glucose deficiency. We performed Western blot and immunohistochemistry to determine the effect of axotomy on the expression and regulation of GRP78 in the facial nucleus (FN). Facial nerve axotomy caused a larger and longer increase of GRP78 in the ipsilateral FN than in the contralateral FN. In right ipsilateral FN, axotomy resulted in elevation of GRP78 protein levels, first detected at 12 h and which reached significant, maximal induction at 24 h (75 +/- 27% increase). GRP78 protein levels decreased at later time points, but remained elevated over sham-operated controls. In contrast, no significant increase in GRP78 concentrations was found in contralateral left FN. Immunocytochemically, positive GRP78 staining was found mainly in the cytoplasm of motoneurons; there was no nuclear staining. Prominent GRP78-immunostaining appeared in axotomized motoneurons at 24 h postaxotomy as compared with the contralateral, unoperated controls. This augmentation was also observed at 4 and 7 days postaxotomy. The possibility that glucose metabolism and GRP78 levels are two parallel events in the injured facial nucleus is discussed.
神经损伤会导致起源神经元细胞体发生代谢和形态变化。已有研究描述了切断轴突后，面神经和舌下运动核中葡萄糖代谢周转率的增加。葡萄糖调节蛋白78 kDa（GRP78）参与细胞蛋白质折叠和亚基组装，并对葡萄糖缺乏作出反应。我们进行了蛋白质免疫印迹和免疫组织化学实验，以确定切断轴突对面神经核（FN）中GRP78表达和调控的影响。面神经切断术导致同侧FN中GRP78的增加幅度更大、持续时间更长，而对侧FN则不然。在右侧同侧FN中，切断轴突导致GRP78蛋白水平升高，在12小时首次检测到，在24小时达到显著的最大诱导水平（增加75±27%）。GRP78蛋白水平在随后的时间点下降，但仍高于假手术对照组。相比之下，在对侧左侧FN中未发现GRP78浓度有显著增加。免疫细胞化学结果显示，GRP78阳性染色主要见于运动神经元的细胞质；无细胞核染色。与对侧未手术的对照组相比，切断轴突后24小时，切断轴突的运动神经元中出现明显的GRP78免疫染色。在切断轴突后4天和7天也观察到这种增强现象。本文讨论了葡萄糖代谢和GRP78水平在受损面神经核中是否为两个平行事件的可能性。
