美托洛尔对心力衰竭大鼠心肌细胞肌浆网 Ca2+释放通道数量及其mRNA表达的影响

目的探讨美托洛尔（倍他乐克）对心力衰竭大鼠心肌细胞肌浆网（SR）钙离子释放通道（RyR2）数量及其mRNA表达的影响.方法通过结扎大鼠左侧冠状动脉建立慢性心力衰竭模型,用倍他乐克进行干预,对照观察血流动力学,[^3H]-ryanodine与左室心肌RyR2最大结合量（Bmax）,RyR2 mRNA表达的水平.结果与对照组（C组）相比,心力衰竭组（H组）左室舒张末压（LVEDP）值显著升高（P〈0.01）,射血分数（EF）值显著降低（P〈0.01）,倍他乐克组（B组）相对于H组LVEDP值显著降低（P〈0.01）,EF值显著升高（P〈0.01）;B组[3H]-ryanodine与RyR2最大结合量显著高于H组,H组[^3H]-ryanodine与RyR2最大结合量显著低于C组,H组RyR2 mRNA表达水平显著低于B组和C组.结论心力衰竭大鼠心肌细胞SR钙离子释放通道数量及RyR2基因表达减少,而倍他乐克则有增加心力衰竭心肌细胞SR钙离子释放通道数量及RyR2基因表达的作用.

Effects of Betaloc on mRNA Expression of Calcium Release Channels of Myocardial Sarcoplasmic Reticulum in Dysfunctional Heart

Objective To study the effect of Betaloc on mRNA expression of Ca 2 release channels (RyR2) of myocardial sarcoplasmic reticulum in dysfunctional heart.Methods Ninety rats were divided into heart failure group, Betaloc group and control group. Hemodynamic parameters,Bmax of [3H]-ryanodine binding RyR2 and RyR2 mRNA concentration were determined.Results Compared with control group, LVEDP was significantly higher in the heart failure group(P<0.01). Compared with the Betaloc group, LVEDP was also significantly higher in the heart failure group(P<0.01).Compared with control group and Betaloc group, EF was significantly lower in heart failure group. Bmax of [3H]-ryanodine bind in g RyR2 in heart failure group was significantly lower than that in control group and Betaloc group (P<0.01). In the RT-PCR assay, the mRNA concentration of RyR2 was also significantly lower in heart failure group than that in the control group and Betaloc group.Conclusion The result indicated that Betaloc could improve the amount and the expression of RyR2 of myocardial sarcoplasmic reticulum(SR) in chronic heart failure and contribute to the improvement of cardiac function.