Increased expression of intercellular adhesion molecule-1 i n mouse focal cerebral ischemia model

Objective To quantitatively measure the temporal profiles of intercellular adhesion molecule-1 (ICAM-1) protein in mouse brain after middle cerebral artery occlusion (MCAO).Methods Adult male CD-1 mice received 0, 3, 6, 12, 24, 48 and 72 hour(s) of permanent MCAO with an intraluminal suture technique. The degree and the extent of occlusion were determined using a laser Doppler flowmeter. ICAM-1 positive expression in ischemic regions was determined immunohisto-chemically and ICAM-1 protein was quantitatively measured using immunoprecipitation and Western blot analysis. Results After MCAO, surface cerebral blood flow (CBF) in the ischemic hemisphere decreased to 9%-15% of the baseline in each time point of 7 to 8 animals. There were no significant differences in CBF measurement during occlusion between groups. Immunohistochemistry showed that ICAM-1 positive microvascular endothelial cells were observed both in the ischemic core and in the perifocal region. There was a tendency for increasing expression of ICAM-1 positive microvascular endothelial cells from the ischemic core to the ischemic margin. Western blot analysis showed that ICAM-1 expression in the ischemic hemisphere began to increase 3 h after MCAO, peaked at 6 h to 12 h, and persisted to 72 h.Conclusions ICAM-1 expression increases in mice with permanent MCAO because ICAM-1 can mediate leukocyte-endothelial adhesion and progression of leukocyte infiltration after permanent focal cerebral ischemia. ICAM-1 is one of the important factors participating in ischemic cerebral damage and pathogenesis of stroke.