[Abnormal abundances of calcium cycling regulatory proteins in rabbit myocytes with heart failure].
OBJECTIVE
To investigate the abnormal abundances of calcium regulatory proteins in rabbit myocytes with failing hearts.


METHODS
Sixteen rabbits were divided into two groups: 8 rabbits with heart failure induced by volume plus pressure overload and 8 sham-operated animals. The hemodynamic parameters and cardiac structure and function were detected via catheterization and echocardiography respectively. L-type calcium channel (LTCC), Ryanodine receptor 2 (RyR2), Sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a), and Na(+)-Ca(2+) exchanger (NCX) protein abundances were determined by Western blot analysis.


RESULTS
The ratio of left ventricular mass to body weight, heart rate and left ventricular end diastolic pressure in heart failure rabbits were significantly increased compared with sham-operated rabbits (P < 0.01), but their left ventricular shorten fraction [(21.3 +/- 4.00)% vs. (36.5 +/- 1.36)%] and ejection fraction (0.45 +/- 0.07 vs. 0.70 +/- 0.02) were decreased (P < 0.01). In heart failure rabbits, the abundances of LTCC and RyR2 were significantly decreased (R(LTCC/actin): 0.287 +/- 0.029 vs. 0.624 +/- 0.009; R(RyR2/actin): 0.106 +/- 0.001 vs. 0.203 +/- 0.011; P < 0.01), whereas the expressions of SERCA2a and NCX were markedly increased (R(NCX/actin): 0.497 +/- 0.015 vs. 0.221 +/- 0.014; R(SERCA2a/actin): 0.611 +/- 0.036 vs. 0.433 +/- 0.008; P < 0.01).


CONCLUSIONS
Reductions of LTCC and RyR2 might contribute to risk factors of systolic dysfunction in failing hearts. In early stage of heart failure, upregulated SERCA2a and NCX protein levels may be helpful for maintaining cardiac performance.
Zou
Cao
C
Department of Cardiology, First Affiliated Hospital of Suzhou University, Suzhou 215006, China.
Liu
Zhi-hua
ZH
Jiang
Bin
B
Miao
Li-yan
LY
Qian
Mei-ying
MY
Zhang
Hua
H
Song
Jian-ping
JP
Yang
Xiang-jun
XJ
Jiang
Ting-bo
TB
Jiang
Wen-ping
WP
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis*; D005260:Female; D006333:Heart Failure / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D019837:Ryanodine Receptor Calcium Release Channel / Q000378:metabolism; D012519:Sarcoplasmic Reticulum / Q000737:chemistry; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000378:metabolism
D002135:Calcium-Binding Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D002118:Calcium