Lee T H, Kato H, Kogure K, Itoyama Y
Department of Neurology, Tohoku University School of Medicine, Sendai, Japan.
Brain Res. 1996 Mar 25;713(1-2):199-210. doi: 10.1016/0006-8993(95)01510-8.
We studied the temporal profile of nerve growth factor-like immunoreactivity (NGF-LI) in the rat brains following 30 min of middle cerebral artery occlusion. The rats were decapitated at 4 h, 1, 3, 7, and 14 days of recirculation. Brain sections at the level of striatum were immunostained against NGF as well as a stress protein, HSP70. Also, double immunostaining of NGF and glial fibrillary acidic protein was performed. In the sham-control rats, NGF-LI was normally present in the cortical and striatal neurons. However, at 4 h of recirculation, there was a significant decrease of NGF-LI in the ischemic cortex and striatum. From 1 day, NGF-LI was absent completely in the ischemic striatum. However, in the ischemic cortex, NGF-LI decreased to the lowest level at 1 day, but it recovered gradually from 3 days and increased significantly to above sham-control level at 7 days. At 14 days of recirculation, NGF-LI returned to a near sham-control level. In the non-ischemic cortex, NGF-LI increased gradually from 4 h with a peak at 7 days, and returned to the sham-control level at 14 days of recirculation. A HSP70 was induced in the ischemic cortex at 1 and 3 days, when there was a significant reduction of NGF-LI. The number of reactive astrocytes increased gradually and NGF-LI in the reactive astrocytes became gradually intense after ischemia. The present finding showing that NGF-LI can be recovered in the stressed cortical neurons suggests a possible involvement of NGF in the process of neuronal survival after focal cerebral ischemia. The expression of NGF in reactive astrocytes indicates that astrocyte may also play a role in supporting neuronal survival after ischemia.
我们研究了大脑中动脉闭塞30分钟后大鼠脑内神经生长因子样免疫反应性（NGF-LI）的时间变化情况。在再灌注4小时、1天、3天、7天和14天时将大鼠断头。对纹状体水平的脑切片进行针对NGF以及一种应激蛋白HSP70的免疫染色。此外，还进行了NGF和胶质纤维酸性蛋白的双重免疫染色。在假手术对照大鼠中，NGF-LI正常存在于皮质和纹状体神经元中。然而，在再灌注4小时时，缺血皮质和纹状体中的NGF-LI显著减少。从1天起，缺血纹状体中完全没有NGF-LI。然而，在缺血皮质中，NGF-LI在1天时降至最低水平，但从3天开始逐渐恢复，在7天时显著增加至高于假手术对照水平。在再灌注14天时，NGF-LI恢复到接近假手术对照水平。在非缺血皮质中，NGF-LI从4小时开始逐渐增加，在7天时达到峰值，并在再灌注14天时恢复到假手术对照水平。在1天和3天时，缺血皮质中诱导出HSP70，此时NGF-LI显著减少。缺血后反应性星形胶质细胞的数量逐渐增加，反应性星形胶质细胞中的NGF-LI也逐渐增强。目前的研究结果表明，应激的皮质神经元中NGF-LI能够恢复，这提示NGF可能参与局灶性脑缺血后神经元存活的过程。反应性星形胶质细胞中NGF的表达表明，星形胶质细胞在缺血后支持神经元存活方面可能也发挥作用。
