[Effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with experimental heart failure].
Zhonghua Xin Xue Guan Bing Za Zhi
; 35(5): 476-9, 2007 May.
Article
em Zh
| MEDLINE
| ID: mdl-17711695
ABSTRACT
OBJECTIVE:
To investigate the effects of metoprolol on cardiac function and myocyte calcium regulatory protein expressions in rabbits with heart failure.METHODS:
Rabbit heart failure model was established by aortic insufficiency induced volume overload followed 14 days later by pressure overload induced by abdominal aorta constricting (HF, n = 11), another 8 rabbits with heart failure were treated with metoprolol (ME) for 6 weeks, sham-operated rabbits (n = 11) served as control. Cardiac function was measured by echocardiography at the end of study. Caffeine-induced calcium transients of myocytes loaded by Fluo-3/AM were observed under Laser scanning confocal microscope. Calcium regulatory protein expression was determined by Western blot analysis.RESULTS:
Compared to control animals, the ejection fractions [EF, (45.7 +/- 3.0)% vs. (72. 6 +/- 5.0)%, P < 0.01] and the amplitude of caffeine-induced calcium transients [(16.0 +/- 3.5) FI vs. (43.5 +/- 6.2) FI, P < 0.01] were significantly decreased while its time to peak was significantly prolonged [(129.8 +/- 14.5) s vs. (52.2 +/- 7.4) s, P < 0.01] in HF rabbits. The RyR2 (0.106 +/- 0.007 vs. 0.203 +/- 0.021, P < 0.01) and the ratio of SERCA2a and NCX (1.22 +/- 0.23 vs. 1.96 +/- 0.12, P < 0.01) were also significantly reduced in myocytes of HF rabbits. Metoprolol significantly attenuated the decrease of EF [(60.2 +/- 5.1)%], the amplitude of calcium transient [(32.8 +/- 5.4) FI], the RyR2 expression (0.164 +/- 0.016) and the ratio of SERCA2a and NCX (1.68 +/- 0.17, all P < 0.05 vs. HF rabbits) and attenuated the increase of the time to peak of caffeine-induced calcium transients [(91.4 +/- 10.9) s, P < 0.05 vs. HF rabbits].CONCLUSION:
Metoprolol could improve the cardiac function possibly by preventing the alterations of calcium regulatory proteins and increasing calcium transients in failing heart.
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Base de dados:
MEDLINE
Assunto principal:
Insuficiência da Valva Aórtica
/
Miócitos Cardíacos
/
Insuficiência Cardíaca
/
Metoprolol
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
Zh
Ano de publicação:
2007
Tipo de documento:
Article