BACKGROUND: Activation of leucocyte and endothelial cell in ischemic area of brain and the expression of adhesive molecule on the surface can cause aggregation and infiltration of leucocyte which deteriorated cerebral injury due to cytotoxicity. Ligustrazine can inhibit thrombosis and improve microcirculation.OBJECTIVE: To observe the effect of ligustrazine on adhesion of leucocyte and endothelial cell in focal area after cerebral ischemia-reperfusion injury.DESIGN: Randomized controlled animal study.SETTING: Second Division of Brain, Department of Neurology, Daping Hospital of the Third Military Medical University of Chinese PLA; Department of Psychiatry, the Second People's Hospital of Yuxi, Yunnan Province.MATERIALS: The experiment was carried out at the Second Cerebral Laboratory of Neurological Department of Daping Hospital Affiliated to the Third Military Medical University of Chinese PLA. A total of 32 male Wistar rats weighing 250-300 g were randomly divided into normal control group (n=8), cerebral ischemia-reperfusion group (n=12) and cerebral ischemia-reperfusion + ligustrazine group (n=12).METHODS: Rats in ligustrazine group were venously injected with 15 g/kg ligustrazine phosphoric acid, and rats in normal control group and cerebral ischemia-reperfusion group were venously injected with the same volume of saline. Cerebral ischemia-reperfusion injury and adhesive changes of leucocyte in focal area after administration of ligustrazine were observed with immunofluorescent labeling technique and micro-ultra-speed imaging system.MAIN OUTCOME MEASURES: ① Adhesive density index of leucocyte of arteriole in focal area after cerebral ischemia-reperfusion injury; ② Adhesive changes of leucocyte in focal area after administration of ligustrazine.RESULTS: All experimental animals were involved in the finalanalysis.① As compared with those in control group, adhesive density index of leucocyte of arteriole in focal area in cerebral ischemia-reperfusion group was increased, broken stress between leucocyte and endothelial cell was decreased remarkably, adhesion was increased obviously, and there was significant difference (P ＜ 0.01). ② As compared with those in cerebral ischemia-reperfusion group, adhesive density index and adhesion of leucocyte in ligustrazine group were decreased and reached the lowest values after 24 hours. Broken stress was increased and maintained at a higher level. There was no significant difference from that in normal control group till 24 hours.CONCLUSION: Ligustrazine can relieve adhesion between endothelial cell and leucocyte after cerebral ischemia-reperfusion injury.