局灶性脑缺血/再灌注时大鼠脑皮质GFAP及c-fos的表达变化

The changes of c-fos and glial fibrillary acidic protein expression following middle cerebral artery occlusion/reperfusion in rats

目的研究大鼠局灶性脑缺血/再灌注时皮质区星形胶质细胞胶质纤维酸性蛋白(GFAP)与神经元c-fos的表达变化。方法70只大鼠,随机分成缺血组及假手术组,缺血组再根据再灌注时间的不同,分别分为再灌注2、4、6、12、24、48、72 h 7个亚组,应用免疫组织化学单标记法、蛋白印迹法观察缺血皮质区各时间点GFAP和c-fos表达,用免疫组织化学双重染色法显示2组再灌注4、24、48 h GFAP和c-fos表达的相互关系。结果大鼠脑缺血2 h再灌注2 h神经元c-fos的表达增加,4 h达高峰,随之下降,2组间各时间点均有差异(P<0.05);于再灌注4 h星形胶质细胞被激活、GFAP表达增加,随时间延长而逐渐升高,于48 h达高峰,随后下降,2组间6、12、24、48、72 h 5个时间点具有差异(P<0.05);且在同一部位,c-fos阳性神经元周围伴有激活的星形胶质细胞表达GFAP。结论脑缺血/再灌注时皮质区星形胶质细胞及神经元均被激活,并伴有GFAP、c-fos的不同的时程规律表达变化。

Objective To study the changes in the expressions of astrocytes glial fibrillary acidic protein （GFAP） and neuronal c - los expression after reperfusion of focal cerebral ischemia in rats. Methods Seventy male rats were di- vided into one sham group and seven ischemia groups, which were reperfused for 2, 4, 6, 12, 24, 48 and 72 h respec- tively. Immunohistochemical single staining and Western blot method were used to study the time course of separate ex- press!ons of c - fos and GFAP in the cerebral cortex after the middle eerebra~ artery occiusion/reperfusion. The immuno- histochemical double staining method was applied to investigate the relation between GFAP and c - fos after 4, 24 and 48 h of reperfusion. Results Significant increase of c - fos expression was observed at 2 h of reperfusion, peak value was reached at 4 h （ P 〈 0.05 ）. The astrocytes were activated at 4 h, with the GFAP expression increasing and approaching its peak value at 48 h, and then beginning to decline. The difference in GFAP expression between the two groups were significant at all time points （ P 〈 0.05 ）. c - los positive neurons surrounded by GFAP positive astrocytes were located in the ischemic cortex. Conclusion The expressions of astrocytic GFAP and neuronal c - los are both activated in the ischemic cortex and proceed along a time course of regular pattern.