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目的:探讨血小板β淀粉样蛋白(Aβ)在动脉粥样硬化(AS)发生中的作用机制以及雌激素受体α(ERα)对血小板淀粉样前体蛋白(APP)代谢的调节作用。方法:分别提取12只6月龄APP/PS1鼠和6只同月龄野生型小鼠的血小板。将所获得的血小板分为3组:正常对照组、APP/PS1组和APP/PS1+ERα激动剂(PPT)组。在APP/PS1+PPT组的血小板悬液中加入PPT溶液;在正常对照组和APP/PS1组的血小板悬液中加入等量生理盐水。ELISA法检测各组血小板释放Aβ的量以及α、β内分泌酶活性;离心提取各组血小板悬液的上清,并将其加入主动脉内皮细胞的培养液中,用流式细胞仪JC-1法检测主动脉内皮细胞线粒体膜电位。结果:与正常对照组相比,APP/PS1组血小板释放Aβ的量明显增加(P<0.01);APP/PS1+PPT组血小板释放Aβ的量与APP/PS1组血小板相比明显减少(P<0.01);APP/PS1+PPT组血小板而α内分泌酶活性较APP/PS1组增强(P<0.01);与对照组血小板的上清相比,APP/PS1组血小板上清可增强血管内皮细胞线粒体膜电位的去极化(P<0.01)。相比之下,APP/PS1+PPT组血小板的上清对血管内皮细胞线粒体膜电位的作用较APP/PS1组血小板的上清明显减弱(P<0.01)。结论:血小板Aβ的过度生成可导致内皮细胞凋亡,这可能是血小板Aβ促进AS形成的机制之一。激活ERα可通过增强α分泌酶介导的血小板APP代谢减少血小板Aβ的生成,为AS的防治提供了新思路和新途径。
AIM: To investigate the role of platelet β-amyloid (Aβ) in the pathogenesis of atherosclerosis (AS) and the regulatory effect of estrogen receptor alpha (α) on platelet amyloid precursor protein (APP) metabolism. Methods: The platelets of 12 APP / PS1 mice of 6 months old and 6 wild mice of the same age were respectively extracted. The obtained platelets were divided into 3 groups: normal control group, APP / PS1 group and APP / PS1 + ERα agonist (PPT) group. The PPT solution was added to the platelet suspension of APP / PS1 + PPT group; the same volume of saline was added to the platelet suspension of normal control group and APP / PS1 group. ELISA method was used to detect the amount of released Aβ and the activity of α and β endocrine enzymes in each group. The supernatant of platelet suspension was extracted by centrifugation and added to the culture medium of aortic endothelial cells. Method to detect aortic endothelial cell mitochondrial membrane potential. Results: Compared with the normal control group, the amount of Aβ released from the platelet of APP / PS1 group was significantly increased (P <0.01). The amount of Aβ released from the platelet of APP / PS1 + PPT group was significantly decreased compared with the platelet of APP / PS1 group (P < 0.01). Compared with APP / PS1 group, APP / PS1 + PPT group had higher platelet α-secretase activity than APP / PS1 group (P <0.01). Compared with control group, platelet supernatant of APP / PS1 group enhanced mitochondria of vascular endothelial cells Depolarization of membrane potential (P <0.01). In contrast, the effect of supernatant of APP / PS1 + PPT group on mitochondrial membrane potential of vascular endothelial cells was significantly weaker than that of APP / PS1 group (P <0.01). Conclusion: Overproduction of platelet Aβ leads to apoptosis of endothelial cells, which may be one of the mechanisms by which platelet Aβ promotes AS formation. Activation of ERα can enhance the secretion of platelet Aβ by enhancing α-secretase-mediated platelet APP metabolism, providing new ideas and new ways for the prevention and treatment of AS.