心衰心脏收缩蛋白分子变化及与收缩力的关系

THE RELATIONSHIP BETWEEN THE MOLECULAR GENE EXPRESSIONOF MYOSIN, ACTIN AND CARDIAC CONTRACTILITY DURING HEART FAILURE

采用ＤＯＣＡ硅胶管皮下埋入法建立大鼠心衰模型，从基因转录水平检测正常与心衰大鼠心肌组织中心肌收缩蛋白分子基因α－ＭＨＣ、β－ＭＨＣ、α－ｃａｒｄｉａｃａｃｔｉｎ、α－ｓｋｅｌｅｔａｌａｃｔｉｎ表达的变化。结果显示：（１）心衰大鼠心肌收缩力指标ｄｐ／ｄｔｍａｘ较正常大鼠明显降低（下降２７．５１％，Ｐ＜０．０１），（２）心衰大鼠与正常大鼠相比，心肌组织中α－ＭＨＣ基因表达水平显著下降（降低２１．４３％，Ｐ＜０．０５），β－ＭＨＣ基因表达水平显著升高（升高６２．４３％，Ｐ＜０．０１）、α－ｃａｒｄｉａｃａｃｔｉｎ基因和α－ｓｋｅｌｅｔａｌａｃｔｉｎ基因表达水平未见明显改变，（３）α－ＭＨＣｍＲＮＡ的含量与心肌收缩力指标ｄｐ／ｄｔｍａｘ值之间存在正相关关系（ｒ＝０．４１４３，ｎ＝４３，Ｐ＜０．０５），β－ＭＨＣｍＲＮＡ的含量与ｄｐ／ｄｔｍａｘ值之间存在负相关关系。（ｒ＝－０．３９０２，ｎ＝４３，Ｐ＜０．０５）。

The animal model of heart failure was set up by means of deoxycorticosteroneacetate impregnated silicone rubber implants in Wistar rats, and gene expression of myocardial contractile protein, α-MHC、β-MHC、α-cardiac actin、α-skeletal actin in normal and heart failure rats were quantitatively analyzed at gene transcription level. The results showed that: (1)The cardiac contractility index dp/dt max in the heart failure rats is significantly lower than that in the normal (decreased by 27.51% , P<0.01). (2) α-MHC mRNA levels in hearts failure rat heart decreased significantly (21.43%, P<0.05), while β-MHC mRNA levels increased significantly (62.43%, P<0.01), but α-cardiac actin mRNA and α-skeletal actin mRNA levels showed no statistical difference in heart failure and normal rat heart. (3) The α-MHC mRNA level was positively correlated with the dp/dt max value (r=0.4143, n=43, P<0.05), while β-MHC mRNA level was negatively correlated with the dp/dt max value (r=-0.3902, n=43, P<0.05). The above results indicate that changes of MHC gene expression in myocardium is the key molecular basis for the decrease of cardiac contractility during heart failure.