[Effects of ACE inhibitor on the calcium transient and calcium handling proteins in ventricular myocytes from rats with heart failure].
OBJECTIVE
To investigate the influence of ACE inhibitor (perindopril) on the contractility and calcium transient and calcium handling proteins in ventricular myocytes from rats with experimental heart failure.


METHODS
Male Wistar rats were randomized to heart failure group treated with perindopril (CHF-T, 3 mg.kg(-1).d(-1)), heart failure group without treatment (CHF-C) and sham-operated group (PS) after heart failure was induced by constricting abdominal aorta for 16 weeks. All groups were further followed up for 12 weeks. Left ventricular myocytes were isolated, and single cell shortening fraction and [Ca(2+)](i) were simultaneously measured through laser scanning confocal microscope under the field stimulation (1.0 Hz). RT-PCR and Western blot were performed to evaluate the level of mRNA and protein of Na(+)-Ca(2+) exchanger (NCX(1)), sarcoplasmic Ca(2+)-ATPase (SERCA(2)) and phospholamban (PLB).


RESULTS
The fraction of cell shortening (FS%) and [Ca(2+)](i max) (nmol/L) were significantly smaller in group CHF-C than group PS (FS%: 7.51 +/- 1.15 vs 13.21 +/- 1.49; [Ca(2+)](i max): 330.85 +/- 50.05 vs 498.16 +/- 14.07; both P < 0.01). And in CHF-T group, FS and [Ca(2+)](i max) were greater than those in CHF-C group. In CHF-C group, the left ventricular mRNA of NCX(1) and PLB were significantly higher than those in PS group (R(NCX)(1)/beta-Actin: 0.51 +/- 0.12 vs 0.19 +/- 0.06, P < 0.01; R(PLB)/beta-Actin: 0.26 +/- 0.12 vs 0.20 +/- 0.08, P = 0.045), yet SERCA(2) mRNA was lower than PS group (0.48 +/- 0.10 vs 0.80 +/- 0.11, P < 0.01). In CHF-T group, the mRNA levels of NCX(1) and SERCA(2) were just in the midst of the CHF-C and PS group, and had statistical significance respectively (all P < 0.05). In CHF - C and CHF - T group, the protein levels of NCX(1) were 1.141 +/- 0.047 and 1.074 +/- 0.081 times PS group, respectively (both P < 0.05), and SERCA(2) protein levels were respectively 0.803 +/- 0.100 and 0.893 +/- 0.084 times as high as in PS group (both P < 0.05). The protein expression of NCX(1) and SERCA(2) were also different between CHF-C and CHF-T groups (both P < 0.05).


CONCLUSIONS
ACE inhibitor could improve cardiac function in CHF through directly enhancing the contractility of single myocardial cell, and these effects were probably mediated by its role in preventing the deleterious changes of calcium transient and calcium handling proteins in CHF.
Wang
Li-chun
LC
Department of Cardiology, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, China.
Ma
Hong
H
He
Jian-gui
JG
Liao
Xin-xue
XX
Mai
Wei-yi
WY
Chen
Wen-fang
WF
Leng
Xiu-yu
XY
Ma
Li
L
Zeng
Wu-tao
WT
Liu
Jun
J
Tao
Jun
J
Dong
Yu-gang
YG
Tang
An-li
AL
Feng
Chong
C
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism; D006333:Heart Failure / Q000188:drug therapy / Q000378:metabolism*; D008297:Male; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism*; D020913:Perindopril / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar
D002147:Calmodulin; D002118:Calcium; D020913:Perindopril