缺血后海马高迁移率族蛋白与星形胶质纤维酸蛋白表达及相关性

Expression and correlation between astrocytes glial fibrillary acidity protein and high mobility group protein in the hippocampus of middle cerebral artery occlusion/reperfusion

目的研究大鼠局灶性脑缺血再灌注星形胶质纤维酸蛋白(GFAP)与高迁移率族蛋白(HMGB1)在海马CA1区表达变化,探讨二者之间的关系。方法采用大脑中动脉栓塞2h制备SD大鼠脑缺血模型,60只雄性SD大鼠随机分为假手术组、缺血再灌注组,按1d、3d、7d、14d、28d时间点再分5个亚组,各时间点处死取脑,用免疫组化和荧光双标结合共聚焦扫描的方法来检测高迁移率族蛋白和星形胶质纤维酸蛋白在脑内海马CA1区表达变化。结果不同时间点缺血再灌注组GFAP、HMGB1表达均高于同时期的假手术组(P<0.05)。缺血再灌注组星形胶质细胞1d、3d、7d逐渐激活增生,7d达到高峰,14d开始下降;HMGB1在1d、3d、7d、14d是表达增加,14d达高峰,28d下降(与前一时间点比较P<0.05)。缺血再灌注组GFAP和HMGB1表达具有相关性(P<0.05),存在HMGB1和GFAP共定位细胞。结论脑缺血再灌注后,海马CA1区HMGB1增加与星形胶质细胞激活成正相关,过度表达的HMGB1和增殖的星形胶质细胞可能与缺血再灌注后神经元的迟发性损伤有关。

Objective To explore the correlation between astrocytes glial fibrillary acidity protein（GFAP） and high mobility group protein（HMGB1） by investigating the expression and location of HMGB1 and GFAP in the hippocampus of middle cerebral artery occlusion/reperfusion（MCAO） in rats.Methods A two-hour MCAO model was adopted in adult male Sprague Dawley（SD） rats to induce a transient cerebral ischemia.Sixty male SD rats were randomly divided into sham-operated group and ischemia-reperfusion group.The rats were killed when they were reperfused for1,3,7,14 and 28d respectively.Immunohistochemical staining and fluorescent double staining combined with confocal scanning were used to analyze the time course of expression of HMGB1 and GFAP in the hippocampl CA1 region after MCAO.Results The difference in GFAP and HMGB1 expression between the two groups（sham-operated group and ischemia-reperfusion group） were significant at all time points（P〈0.05）.The astrocytes were activated on 1d,with the GFAP expression increasing and approaching its peak value on 7d,and beginning to decline;at the same time,HMGB1 increased in the hippocampal CA1 region during 1d to 14d,but not on 28d after MCAO,its peak was reached on 14d（compared with previous time point in the ischemia-reperfusion group P〈0.05）.The expression of GFAP and HMGB1 were correlative and HMGB1 siginficantly co-localized with GFAP in the hippocampl CA1 region in ischemia-reperfusion group（P〈0.05）.Conclusions The expression of HMGB1 was closely related with activation of astrocytes in the hippocampal CA1 region after MCAO.The excessive expression of HMGB1 and activation of astrocytes might in turn contribute to the pathological process of delaying neuronal injury after MCAO.