活血化瘀中药对慢性间歇性低氧介导的动脉粥样硬化过程中血小板活化及PI3Kβ表达的影响

Obstructive sleep apnea (OSA) caused by chronic intermittent hypoxia (CIH) can cause vascular endothelium damage, promote the development of atherosclerosis (AS). How the CIH induced AS remains unclear. Platelet activation is one of the critical roles during the development of AS. High platelet activation situation among OSA patients is regarded as a specific characteristic of "Blood stasis"on the basis of traditional Chinese medicine. Our previous studies have shown that high PI3Kβ expression among OSA patients, while PI3Kβ is involved in the progress of platelet activation. We infer that PI3Kβ plays an important role in the development of CIH-induced AS. Previous studies have shown that Tetramethylpyrazine (TMP), an bioactive component of Chuanxiong, has certain effect on anti-platelet and anti-AS. In the current study, we investigate the role of PI3Kβ in human platelet activation model in vitro induced by CIH and in AS model of ApoE-/- rats induced by CIH and fat dietary feed in vivo. Meanwhile, the effects of TMP on platelet activation and vascular endothelial injury are also investigated. We aim to explore the role of PI3Kβ in the development of platelet activation during CIH-induced AS and the mechanism or target of activated blood circulation of Chinese drugs. To provide experimental evidence for their clinical application in the prevention and treatment of vascular secondary diseases induced by OSA.

阻塞性睡眠呼吸暂停（OSA）导致的慢性间歇性低氧（CIH）可引起血管内皮损伤，促进动脉粥样硬化（AS）的发生发展，但CIH介导AS发生的机制尚不明确。血小板活化是AS形成的关键环节之一，OSA患者存在血小板活化状态与中医血瘀证密切相关。课题组前期研究发现PI3Kβ在OSA患者血小板上高表达，同时发现其参与血小板活化的过程。推测PI3Kβ可能在CIH介导AS的发生过程中扮演了重要角色。研究证实活血化瘀中药川芎的有效成分川芎嗪保护血管内皮、抗血小板及抗AS疗效肯定。本研究借助CIH诱导人血小板建立体外血小板活化模型，以CIH复合高脂饲料喂养ApoE基因敲除小鼠诱发AS动物模型，以PI3Kβ为切入点，观察CIH介导AS形成过程中血小板活化与PI3Kβ的表达变化及川芎嗪的干预效应，探讨PI3Kβ在其中的作用机制以及活血化瘀中药的作用靶点，为活血化瘀药物防治OSA继发血管病变的临床应用提供实验依据。

阻塞性睡眠呼吸暂停（OSA）导致的慢性间歇性低氧可引起血管内皮损伤，促进动脉粥样硬化的发生发展，但慢性间歇性低氧介导动脉粥样硬化发生的机制尚不明确。血小板活化是动脉粥样硬化形成的关键环节之一，OSA患者存在血小板活化状态与中医血瘀证密切相关。课题组前期研究发现PI3Kβ在OSA患者血小板上高表达，同时发现其参与血小板活化的过程。推测PI3Kβ可能在慢性间歇性低氧介导的动脉粥样硬化形成过程中扮演了重要角色。围绕以上假说，本项目体外研究借助间歇性低氧（IH）诱导人血小板建立体外血小板聚集活化模型，研究发现：①IH可诱导人血小板体外聚集、活化，同时发现被IH体外诱导聚集、活化的血小板Akt磷酸化及PI3Kβ蛋白表达明显增强。②川芎嗪可明显降低由IH体外诱导的血小板聚集及活化水平，其机制与降低血小板钙离子内流、抑制PI3Kβ的激活相关。体内研究以慢性间歇性低氧复合高脂饲料喂养ApoE基因敲除小鼠诱发动脉粥样硬化动物模型，以PI3Kβ为研究切入点，观察慢性间歇性低氧介导动脉粥样硬化形成过程中血小板活化与PI3Kβ的表达变化及川芎嗪的干预机制，研究发现：① 慢性间歇性低氧复合高脂饲料可明显促进ApoE基因敲除小鼠主动脉血管内皮损伤、粥样硬化斑块的形成，其过程中伴随Akt磷酸化的增加及PI3Kβ蛋白及mRNA表达的增强。② 川芎嗪(0.15g/kg/d)可明显改善小鼠模型血脂异常水平，抑制血小板活化水平及炎症反应，减轻慢性间歇性低氧介导的ApoE基因敲除小鼠主动脉组织内皮损伤及粥样硬化病变的程度，其机制与抑制PI3K/Akt信号通路的激活，下调PI3Kβ的表达相关。本项目发表学术论文13篇，其中SCI收录5篇，项目负责人于项目执行期间入选北京市科技新星人才计划。本项目的研究完成为活血化瘀药物川芎嗪防治OSA继发血管病变的临床应用提供了较高水平的实验证据，为后续研究的开展奠定了较好的基础。