[Eukaryotic expression vector pcDNA3-HERG transfection inhibits angiotensin II induced neonatal rabbit ventricular myocyte hypertrophy in vitro].
OBJECTIVE
To explore the effects of eukaryotic expression vector pcDNA3-HERG transfection on angiotensin II (Ang II) induced myocyte hypertrophy in cultured neonatal rabbit ventricular 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 ventricular 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 (APD(90)) was prolonged by 19.8% (P < 0.01), without signs of myocyte hypertrophy at 6 h post Ang II stimulation, APD(90) 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 transfection upregulated I(HERG) tail current (3.6-fold higher than I(Kr)-rapidly activating delayed rectifier potassium current, P < 0.01). HERG gene transfection also accelerated and repolarization and a shortened APD(90) and inhibited myocyte hypertrophy and CaN activation induced by Ang II.


CONCLUSIONS
Ang II induced prolongation of APD(90) 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.
Department of Cardiology, Henan Provincial People's Hospital, Zhengzhou 450003, China. zhaoyonghui2000@stu.xjtu.edu.cn
Yong-hui
YH
Zhao
Chang-cong
CC
Cui
Yu
Y
Li
Chen
C
Huang
D000804:Angiotensin II / Q000502:physiology; D000818:Animals; D019703:Calcineurin / Q000378:metabolism; D002478:Cells, Cultured; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D006352:Heart Ventricles / Q000166:cytology; D006801:Humans; D006984:Hypertrophy / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D010957:Plasmids; D011817:Rabbits; D014162:Transfection
D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D000804:Angiotensin II; D019703:Calcineurin