Ito Umeo, Kuroiwa Toshihiko, Nagasao Jun, Kawakami Emiko, Oyanagi Kiyomitsu
Department of Neuropathology, Tokyo Metropolitan Institute for Neuroscience, Tokyo, 2-6, Musashidai, Fuchu-shi, Tokyo 183-8526, Japan.
Stroke. 2006 Aug;37(8):2134-9. doi: 10.1161/01.STR.0000231875.96714.b1. Epub 2006 Jun 29.
Because the recovery process of axon terminals, synapses, and spine-dendrites in the ischemic penumbra of the cerebral cortex is obscure, we studied the temporal profile of these structures up to 12 weeks after the ischemic insult, using a gerbil model.
Stroke-positive animals were selected according to their stroke index score during the first 10-minute left carotid occlusion done twice with 5-hour interval. The animals were euthanized at various times after the second ischemic insult. Ultra-thin sections including the 2nd to 4th cortical layers were obtained from the neocortex coronally sectioned at the infundibular level, in which the penumbra appeared. We counted the number of synapses, spines and multiple synapse boutons, measured neurite thickness, and determined the percent volume of the axon terminals and spines by Weibel point counting method.
The number of synapses, synaptic vesicles and spines and the total percent volume of the axon terminals and spines decreased until the 4th day. From 1 to 12 weeks after the ischemic insult, these values increased to or exceeded the control ones, and neuritic thickening and increase in number of multiple synapse boutons occurred.
In the ischemic penumbra, the above structures degenerated, with a reduction in their number and size, until 4 days and then recovered from 1 to 12 weeks after the ischemic insult.
由于大脑皮质缺血半暗带中轴突终末、突触以及棘突-树突的恢复过程尚不明确，我们利用沙鼠模型研究了缺血损伤后长达12周这些结构的时间变化情况。
在间隔5小时进行两次持续10分钟的左侧颈动脉闭塞过程中，根据卒中指数评分选择卒中阳性动物。在第二次缺血损伤后的不同时间点对动物实施安乐死。从漏斗水平冠状切片的新皮质获取包含第2至4皮质层的超薄切片，其中会出现半暗带。我们计数突触、棘突和多个突触扣结的数量，测量神经突厚度，并通过韦贝尔点计数法确定轴突终末和棘突的体积百分比。
突触、突触小泡和棘突的数量以及轴突终末和棘突的总体积百分比在第4天前减少。在缺血损伤后1至12周，这些值增加至或超过对照值，并且出现神经突增粗和多个突触扣结数量增加的情况。
在缺血半暗带中，上述结构在缺血损伤后4天内发生退化，数量和大小减少，然后在1至12周后恢复。
