真核表达质粒pcDNA3-HERG转染抑制血管紧张素Ⅱ诱导乳兔心肌细胞肥大  

Eukaryotic expression vector pcDNA3-HERG transfection inhibits angiotensin Ⅱ induced neonatal rabbit ventricular myocyte hypertrophy in vitro

作　　者：赵永辉[1] 崔长琮[2] 李宇[2] 黄辰[3] 

机构地区：[1]河南省人民医院心内科,郑州450003 [2]西安交通大学第一医院心内科 [3]西安交通大学第一医院环境和疾病相关基因教育部重点实验室

出　　处：《中华心血管病杂志》2009年第10期931-935,共5页Chinese Journal of Cardiology

摘　　要：目的探讨HERG基因真核表达质粒pcDNA3-HERG（编码人快激活延迟整流钾通道d亚单位）转染抑制血管紧张素（Ang）Ⅱ诱导乳兔心室肌细胞肥大的电生理机制。方法培养乳兔心室肌细胞，观察10^-7mol／LAngⅡ作用6h和48h心肌肥大指标（细胞体积、总蛋白含量及膜电容）、动作电位时程（APD）及钙调神经磷酸酶（CaN）活性的变化。以真核表达质粒pcDNA3-HERG转染心室肌细胞，观察转染细胞经AngⅡ诱导48h后上述指标的变化。结果AngⅡ作用6h，心室肌细胞动作电位复极达90％时程（APD90）延长19．8％（P〈0．01），而此时并无心肌肥大和CaN活性增加。AngⅡ作用48h，心室肌细胞APD90延长22．1％（P〈0．01），细胞体积、总蛋白含量、膜电容以及CaN活性分别增加40．4％、40．4％、38．2％、114．7％（P均〈0．01）。pcDNA3-HERG转染可过度表达IHERC，其尾电流密度约为正常对照组快激活延迟整流钾电流（IKr）尾电流密度的3．6倍（P〈0．01），可促进复极，明显缩短AngⅡ引起的APD90延长（P〈0．01），显著抑制AngⅡ诱导心肌肥大和CaN活性增加。结论AngⅡ诱导乳兔心室肌细胞肥大过程中，APD延长并非继发于而是早于心肌肥大。APD延长，继而导致Ca^2＋内流和胞内Ca^2＋增加，激活CaN信号通路可能在AngⅡ诱导心肌肥大中起重要作用。Objective To explore the effects of eukaryotic expression vector pcDNA3-HERG transfection on angiotensin Ⅱ （ Ang Ⅱ ） induced myocyte hypertrophy in cultured neonatal rabbit ventrieular myocytes. Methods Neonatal rabbit ventricular myocytes and eukaryotic expression vector pcDNA3-HERG transfected ventricular myocytes were cultured in Dulbecco＇s-modified Eagle medium （DMEM）, containing 1% fetal bovine serum （FBS） for 6 h, then stimulated with Ang Ⅱ （10^-7 mol/L） for 48 h. Control ventrieular myocytes were cultured in Dulbecco＇s-modified Eagle medium （ DMEM ）, containing 1% fetal bovine serum （FBS） for 54 h. At 6 and 54 h, myocyte hypertrophic parameters including myocyte volume, total protein content and membrane capacitance, action potential duration （APD） and Calcineurin （CaN） activity were measured. Results Compared to control myocytes, APD at 90% repolarization （APD90） was prolonged by 19. 8% （P 〈 0. 01 ）, without signs of myocyte hypertrophy at 6 h post Ang Ⅱ stimulation, APD90 was prolonged by 22. 1% （ P 〈 0. 01 ） , myocyte volume, total protein content and membrane capacitance and CaN activity were significantly increased by 40.4%, 40.4%, 38.2% and 114. 7% respectively （all P 〈0. 01 ） at 48 h after Ang Ⅱ stimulation. HERG gene transfeetion upregulated IHERG tail current （3.6-fold higher than IKr -- rapidly activating delayed rectifier potassium current, P 〈 0. 01 ）. HERG gene transfection also accelerated and replarization and ashortened APD90 and inhibited myocyte hypertrophy and CaN activation induced by Ang Ⅱ . Conclusions Ang Ⅱ induced prolongation of APD90 is directly associated with myocyte hypertrophy by increasing the Ca^2＋ influx and resulting in the increment of intracellular Ca^2＋ and activation of CaN reaction pathway.

关 键 词：肌细胞 心脏 肥大 血管紧张素Ⅱ 质粒 转染 

分 类 号：R686[医药卫生—骨科学]