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

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(P0.05).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 P0.05).The expression of GFAP and HMGB1 were correlative and HMGB1 siginficantly co-localized with GFAP in the hippocampl CA1 region in ischemia-reperfusion group(P0.05).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.