Abstract: This paper investigated the possible mechanism underlying the protective effect of Zige lyophilized powder for injection against the microvascular permeability after cerebral ischemia- reperfusion injury of rats in the celebral microcirculation.320 male Sprague- Dawley rats were randomly divided into sham group,model group,puerarin injection group,nimodipine injection group,three groups of Zige lyophilized powder.Middle cerebral artery occlusion( MCAO) model was produced by using an intraluminal filament technique in rats. Drugs were administered intravenously( i.v.) 2 h after MCAO and reperfusion for 1,4,7 and 14 d.The expression levels of MMP-9,ZO- 1,Occludin and Claudin- 5 protein of the brain microvessel in the lateral ischemic cerebral cortex were detected by Western blot. In reperfusion for 4,7 and 14 d,compared with model group,Zige lyophilized powder groups( 16.40,32.70 and 65.40 mg·kg- 1) could reduce MMP-9 protein expression in microvessel of the lateral ischemic cerebral cortex,and could increase ZO- 1,Occludin and Claudin- 5 protein expression in the corresponding time.These results suggested that the protective effect of Zige lyophilized powder for injection on the microvascular permeability after cerebral ischemia- reperfusion injury was mediated by reducing MMP-9 and increasing ZO-1,Occludin,Claudin-5 protein expression.