脑缺血再灌注(CI/R)损伤内皮细胞，启动血小板膜糖蛋白GPIb为核心的血栓炎性病变，破坏血脑屏障(BBB)。Epac是cAMP直接激活的新型效应分子，缺氧致内皮屏障渗漏时伴随Epac通路活性下调，但它与CI/R损伤关系鲜见报道。我们发现，阻断GPIb可改善MCAO小鼠血栓炎性病变，增强BBB功能，减少颅内出血，其机制尚未阐明。预实验显示CI/R小鼠Epac下调并抑制Rap1，提示Epac/Rap1通路可能参与CI/R发病，阻断GPIb通过调控Epac通路保护BBB可能是防治CI/R损伤并降低出血转归的新思路。为验证此假说，本项目拟建立小鼠MCAO和脑血管内皮细胞缺氧模型，应用免疫荧光、激光共聚焦、siRNA等技术及药理学工具药，研究GPIb调控脑缺血损伤致BBB渗漏的分子机制，为靶向阻断GPIb治疗脑卒中的新策略提供进一步的实验依据。

Cerebral ischemia reperfusion (CI/R) can damage vascular endothelial cells, activate the central role of platelet membrane glycoprotein GPIb, induce thrombo-inflammation, and destroy blood-brain barrier (BBB). Epac (exchange factor directly activated by cyclic AMP-activated guanine nucleotide) belongs to a new family of proteins that can directly mediate the action of the intracellular second messenger cAMP by activating a downstream the Raslike small GTPase Rap1. Hypoxia–reoxygenation (H/R) induced inactivation of Epac pathway in cultured vascular endothelial cells accompanied by hyperpermeability and loss of barrier function. However, whether Epac plays a role in CI/R injury is not well known. We found that blocking GPIb could improve the thrombo-inflammatory lesions, enhance BBB function, alleviate CI/R injury and reduce intracranial hemorrhage, but the mechanism has not been clarified. Preliminary experiments showed that Epac in CI/R mice decreased and inhibited Rap1 production, suggesting that cAMP-mediated Epac/Rap1 pathway might be involved in the pathogenesis of CI/R, blocking GPIb regulation of Epac/Rap1 pathway to protect BBB might be a new way to prevent CI/R injury and reduce intracerebral hemorrhage. To prove this hypothesis, we will establish MCAO model in mice and H/R model in cerebral vascular endothelial cell. Meanwhile, immunofluorescence, laser confocal, siRNA and other technologies and pharmacological tools will also be used. This study will clarify the potential molecular mechanism of the role of GPIb through Epac/Rap1 pathway in regulation BBB, aggravating CI/R injury, may provide further experimental basis for new treatment strategy of stroke by targeting blockade of GPIb.