Platelet-endothelial cell interaction in brain microvessels of angiotensin II type-2 receptor knockout mice following transient bilateral common carotid artery occlusion.

The purpose of this study was to investigate the behavior of platelets (rolling and adhesion) in cerebral microvessels of angiotensin II type-2 receptor-knockout (AT2RKO) mice after transient bilateral carotid artery occlusion using intravital fluorescence microscopy. Twenty AT2RKO mice, consisting of 11 mice in the sham group and 9 mice in the ischemia reperfusion group (reperfusion after 15 min of bilateral, total carotid artery occlusion) were used in this study. The hole traversed the bone and dura mater, but arachnoid, pia mater, and cerebral parenchyma were preserved. Platelets were harvested from donor mice and stained using carboxyfluorescein diacetate succinimidyl ester. The number of platelets showing rolling and adhesion to pial vessels in AT2 deficient mice at 3 and 6 h after cerebral ischemia reperfusion was significantly higher than that in the sham group (P < 0.05). In addition, AT2 receptor has an inhibitory role in platelet rolling and adhesion after cerebral ischemia reperfusion.