星形胶质细胞活化在局部脑缺血扩布性抑制中的作用

目的研究树鼩局部脑血栓形成过程中,缺血对侧皮层白细胞介素（interluekin,IL）-8水平及星形胶质细胞（astrocyte,AS）胶质纤维酸蛋白（glial fibrillary acidic protein,GFAP）表达的改变,并探讨扩布性抑制（spreading depression,SD）的可能机制。方法采用光化学反应诱导树鼩血栓性局部脑缺血,经免疫组化法和酶联免疫吸附分析法分别检测缺血对侧星形胶质细胞GFAP表达的灰度值及脑组织IL-8水平,并观察不同浓度IL-8对体外培养条件下星形胶质细胞增殖的影响。结果脑血栓形成后72h缺血对侧皮层IL-8水平及GFAP表达明显增加（P〈0.01）,于培养的星形胶质细胞内加入不同浓度（0.1-1.0μg/ml）IL-8,GFAP阳性细胞数呈时间与剂量依赖方式增加（P〈0.01）。结论脑血栓形成后缺血对侧皮层GFAP表达的改变与IL-8水平升高所致AS活化有关,可能是引起SD的重要因素。

Possible Mechanism of Astrocytes Reaction and Spreading Depression After Focal Cerebral Thrombosis in Tree Shrews

Objective To investigate the changes of expression of glial fibrillary acidic protein（GFAP） of astrocytes and the interluekin-8（IL-8） levels in the contralateral cortex and to explore the possible mechanism of spreading depression（SD） during focal cerebral thrombosis. Methods The focal cerebral thrombotic ischemia was induced by photochemical reaction in tree shrews. The absorbance of GFAP expression in astrocytes was detected by immunohistochemistry and IL-8 levels were detected by enzyme-linked immunosorbent assay（ELISA） in the ischemic contralateral cortex after treating cultured cells with the IL-8 of different concentration（ 0.1μg - 1.0μg/mL）. Results The GFAP expression and IL-8 levels increased markedly（ P 〈 0. 01） in the ischemic contralateral cortex at 72h after focal cerebral thrombosis. After adding IL-8 into cultured cells, the number of GFAP positive cells was increased markedly in dose- and time-dependent mode（ P 〈 0. 01）. Conclusion The change of contralateral GFAP expression may involve the astrocytes activation due to increase of IL-8 level, it may be an＇important factor of leading to SD after focal cerebral thrombosis.