室旁核大电导钙激活钾通道下调介导慢性心力衰竭大鼠交感神经兴奋亢进  

Downregulation of large conductance calcium-activated potassium channels in paraventricular nucleus contributes to sympathoexcitation in rats with chronic heart failure

作　　者：王仁俊 温美玲 周琴 未晓巍 李华 赵永斌 齐云峰 栾剑 周晓馥 Wang Renjun, Wen Meiling, Zhou Qin, Wei Xiaowei, Li Hua, Zhao Yongbin, Qi Yunfeng, Luan Jian, Zhou Xiaofu(Departments of Biotechnology, College of Life Science, Jilin Normal University, Siping 136000, China)

机构地区：[1]吉林师范大学生命科学学院生物技术系,四平136000

出　　处：《中华心血管病杂志》2018年第3期178-186,共9页Chinese Journal of Cardiology

基　　金：国家自然科学基金（81202527）;吉林省科技发展计划（20130522002JH）

摘　　要：目的观察慢性心力衰竭（CHF）大鼠室旁核内大电导钙激活钾通道（BKCa）的变化及其与交感神经活动的关系。方法雄性Wistar大鼠，6~7周龄，随机数字表法分为2组，即假手术组和CHF组。通过结扎冠状动脉左前降支的方法建立大鼠CHF模型，假手术组仅穿线不结扎。建模术后2周，对大鼠行下丘脑室旁核慢性灌注BKCa选择性阻断剂IBTX术，取假手术组和CHF组大鼠各24只，进一步分成8个亚组，即假手术＋溶剂人工脑脊液（aCSF）组、CHF＋aCSF组、假手术＋IBTX低剂量组、CHF＋IBTX低剂量组、假手术＋IBTX中剂量组、CHF＋IBTX中剂量组、假手术＋IBTX高剂量组和CHF＋IBTX高剂量组，每组6只大鼠，IBTX低、中、高剂量分别为0.125、1.25、12.5 nmol/nl。另取建模术后2周大鼠，行下丘脑室旁核微量注射病毒术，取假手术组和CHF组大鼠各12只，进一步分成4个亚组，即假手术病毒对照组、假手术基因敲减KCNMB4组、CHF病毒对照组和CHF基因敲减KCNMB4组，每组6只大鼠。超高分辨率小动物超声实时影像系统测定各组大鼠心功能指标，包括左心室射血分数（LVEF）、左心室舒张末期容积（LVEDV）和左心室舒张末期内径（LVEDD）等。进一步对大鼠行右侧颈总动脉插管，通过PowerLab生物信号采集与分析系统，采集大鼠的平均动脉压（MAP）、左心室收缩压（LVSP）和左心室舒张末期压（LVEDP）等指标。在肾脏部位游离出肾交感神经，记录肾交感神经放电（RSNA），心电图采用标Ⅱ导联记录，同步得到心率。分别记录在药物或病毒干预后4周上述各指标变化。待超声心动图、血液动力学和肾交感神经记录结束后，经大鼠腹主动脉采血，ELISA法测定大鼠血浆去甲肾上腺素（NE）及血清N末端B型利钠肽原（NT-proBNP）水平。取血结束后取大鼠心脏及肺脏称重，计算右心室体重比和肺重比。对大鼠心脏进行ObjectiveTo elucidate the association between large conductance calcium-activated potassium channels （BKCa） in the paraventricular hypothalamic nucleus （PVN） and sympathetic outflow in rats with chronic heart failure （CHF） .MethodsMale Wistar rats （6-7 weeks old） were randomized to sham operated group and CHF group （coronary artery ligation） . Two weeks after operation, BKCa inhibitor Iberiotoxin （IBTX） was infused into PVN by osmotic minipumps, rats were divided into following groups： sham＋aCSF, CHF＋aCSF, sham＋low dose IBTX （0.125 nmol/nl） , CHF＋low dose IBTX, sham＋moderate dose IBTX （1.25 nmol/nl） , CHF＋moderate dose IBTX, sham＋ high dose IBTX （12.5 nmol/nl） , and CHF＋high dose IBTX （n=6 each） . Additional rats were grouped as follows： sham＋vehicle, sham＋KCNMB4 knockdown （by rAAV2-KCNMB4 shRNA virus injection in PVN） , CHF＋vehicle, CHF＋ KCNMB4 knockdown group （n=6 each） . The cardiac function was determined by echocardiography, left ventricular hemodynamics were measured invasively, renal sympathetic nerve activity （RSNA） was recorded at 6 weeks after coronary artery ligation or sham operation. The contents of norepinephrine （NE） and N-terminal pro-B-type natriuretic peptide （NT-proBNP） in plasma were determined by enzyme-linked immunosorbent assay. The protein and mRNA expression of KCNMB4 in PVN were measured by immunofluorescence staining, Western blot, and real-time PCR, mRNA expression of BKCa in PVN was detected by real-time PCR.ResultsCompared with the sham operation group, the cardiac function of the heart failure group was significantly reduced （P〈0.05） , and the plasma NE and the serum NT-proBNP were significantly elevated （P〈0.05） . The protein and mRNA expression of KCNMB4 in PVN were obviously down-regulated in CHF rats （P〈0.05） . After perfusion of IBTX or KCNMB4 knockdown by microinjection of rAAV2-KCNMB4 shRNA virus,right ventricular weight/body weight and lung weight/body weight ratio as we

关 键 词：心力衰竭 下丘脑室旁核 大电导钙激活钾通道 交感神经系统 

分 类 号：R541.6[医药卫生—心血管疾病]