小胶质细胞P2X7信号通路介导室旁核OT和AVP能神经元敏感化参与急性心肌梗死的调控机制

The mortality and incidence of acute myocardial infarction (AMI) showed a trend of escalation year by year. Furthermore, the pathogenesis of AMI is complicated and the special therapeutic strategy for AMI is insufficient. In our previous study, we demonstrate that the microglia in hypothalamic paraventricular nucleus were activated induced by AMI and the expression of P2X7 receptor protein was up-regulated in time-dependent manner in the progress of AMI. So far, the regulative mechanism of the P2X7 receptor on AMI induced by myocardial ischemia has not been reported. Based on our previous study, we would adopt AMI animal model of rats and P2X7-/- mouse as research object, combining with in vivo and in vitro experiment, to investigate the molecular and neural regulative muchanism of P2X7 receptor on vasopressin (AVP) and oxytocin (OT) neurons sensitization. In order to explorate the neural signaling network involved in the regulative effects of P2X7 receptor on AMI, we consider inflammatory cytokines IL-1βas research access and adopte multiple electrophysiological, molecular experimental research methods such as gene knockout, si-RNA, brain area microinjection, westernblot, RT-PCR, immunohistochemistry, patch-clamp, extracellular nerve discharges recording and HLPC. This research would clarify the the neural and molecular mechanism of P2X7 receptor in hypothalamic paraventricular nucleus on peripheral sympathetic nervous activity and cardiac function in AMI rats. Meanwhile, these research would be looked forward to provide new drug target for AMI treatment and theoretical basis for research.

急性心肌梗死发病率及死亡率呈逐年上升趋势，其发病机制复杂且缺乏特异性的治疗措施。我们最近的研究发现急性心肌梗死激活了下丘脑室旁核内小胶质细胞并伴随有膜蛋白P2X7的高表达，其对急性心肌梗死的调控机制未见报道。本课题在已有研究的基础上，拟采用大鼠、P2X7-/-小鼠急性心肌梗死模型为研究对象，结合在体及离体实验，应用基因敲除、si-RNA、脑核团微量注射、蛋白免疫印迹、RT-PCR、免疫组化、膜片钳、细胞外记录神经放电、HLPC等电生理及分子生物学手段，以小胶质细胞P2X7受体蛋白激活后释放的炎性细胞因子IL-1β为研究切入点，从不同角度深入探讨小胶质细胞P2X7受体蛋白对OT及AVP能神经元敏感化的分子机制及神经信号网络。阐明室旁核小胶质细胞P2X7受体对急性心肌梗死大鼠外周交感神经紧张性及心功能的神经调控及分子作用机理，以期为急性心肌梗死的治疗提供新的药物作用靶点和理论依据。

脑内特定核团调控急性心肌梗死是治疗该疾病的主要手段之一。下丘脑室旁核在调控大鼠急性心肌梗死过程中具有重要作用，抑制小胶质细胞激活可以减轻急性心肌梗死损伤，提示下丘脑室旁核对急性心肌梗死损伤大鼠外周交感活动起重要调节作用。本项目研究了抑制室旁核区小胶质细胞激活减轻心梗损伤、衰减肾交感神经紧张性的作用与机制。首先，我们发现并证实：心肌梗死诱使下丘脑室旁核小胶质细胞激活，且其激活与其胞膜P2X7受体生理活动改变相关联；其次，在体与离体细胞实验研究发现并证实：激活的小胶质细胞释放炎症细胞因子IL-1β，其能敏感化OT与AVP能神经元、进一步影响肾交感神经紧张性、加重急性心肌梗死损伤。这些研究结果不仅丰富了神经调控内脏缺血性损伤的理论，更为急性心肌梗死损伤的临床治疗提供新策略。在本项目的资助下，已发表SCI论文1篇，获授权专利2项。