Du Dongshu, Jiang Meiyan, Liu Min, Wang Jin, Xia Chunmei, Guan Ruijuan, Shen Linlin, Ji Yonghua, Zhu Danian
Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Shanghai 200444, PR China.
Oregon Hearing Research Center, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA.
Neurosci Lett. 2015 Feb 5;587:22-8. doi: 10.1016/j.neulet.2014.12.026. Epub 2014 Dec 15.
Several pieces of evidence indicate that the microglial P2X7 receptor (P2X7R) regulate cardiovascular activities. We explored the possible roles of microglial P2X7R in the PVN mediated sympathoexcitatory responses in acute myocardial infarction (AMI) rat. Sprague-Dawley rats underwent coronary artery ligation to induce AMI. The rats received intraperitoneal administration of the P2X7R antagonist Brilliant Blue-G (BBG, 25 or 50 mg kg(-1), once a day for 5 days) prior to myocardial ischemia. Other rats received bilateral microinjection of P2X7R-siRNA (0.015 or 0.03 nmol 0.1μl per side, once a day for 2 days) targeting P2X7R mRNA into the PVN prior to myocardial ischemia. First, we examined the ATP levels and protein expression P2X7R in the PVN in different ischemia time groups, and we found that the change of P2X7R was positive correlated with the ATP levels in a time-dependent manner. The double-immunofluorescence evidence showed that P2X7R was mainly co-localizated with the microglial marker Iba-1 in the PVN. Second, gene knockdown of P2X7R with P2X7-siRNA or inhibition of P2X7R with BBG reduce the mRNA and protein expression of IL-1β and TNF-α in the PVN of AMI rat. Third, microinjected P2X7-siRNA also suppressed the up-regulation of P2X7R, oxytocin and vasopressin in the PVN of AMI rats. Fourth, P2X7-siRNA and BBG also attenuated the renal sympathetic nerve activity (RSNA) in the AMI rats. Our results indicate that microglial P2X7R activation in PVN mediating the production of proinflammatory cytokines that activate oxytocinergic and vasopressinergic neuron, which augmented the RSNA in the AMI rat.
多项证据表明，小胶质细胞P2X7受体（P2X7R）调节心血管活动。我们探讨了小胶质细胞P2X7R在急性心肌梗死（AMI）大鼠下丘脑室旁核（PVN）介导的交感兴奋反应中的可能作用。将Sprague-Dawley大鼠进行冠状动脉结扎以诱导AMI。在心肌缺血前，大鼠腹腔注射P2X7R拮抗剂亮蓝G（BBG，25或50 mg·kg⁻¹，每天一次，共5天）。其他大鼠在心肌缺血前双侧脑室内注射针对P2X7R mRNA的P2X7R-siRNA（每侧0.015或0.03 nmol/0.1μl，每天一次，共2天）。首先，我们检测了不同缺血时间组PVN中ATP水平和P2X7R蛋白表达，发现P2X7R的变化与ATP水平呈时间依赖性正相关。双重免疫荧光证据显示，P2X7R主要与PVN中小胶质细胞标志物离子钙结合衔接分子1（Iba-1）共定位。其次，用P2X7-siRNA敲低P2X7R基因或用BBG抑制P2X7R可降低AMI大鼠PVN中白细胞介素-1β（IL-1β）和肿瘤坏死因子-α（TNF-α）的mRNA和蛋白表达。第三，脑室内注射P2X7-siRNA也抑制了AMI大鼠PVN中P2X7R、催产素和血管加压素的上调。第四，P2X7-siRNA和BBG也减弱了AMI大鼠的肾交感神经活动（RSNA）。我们的结果表明，PVN中小胶质细胞P2X7R的激活介导促炎细胞因子的产生，这些细胞因子激活催产素能和血管加压素能神经元，从而增强了AMI大鼠的RSNA。
