目的探讨急性心肌梗死大鼠心肌组织中L型钙通道α1,β亚单位(Cacna1c、Cacnb2)、兰尼碱受体(Ryr2)、肌浆网钙ATP酶(Serca2a)、钠-钙交换体(Ncx1)等钙离子调控相关基因表达的变化。方法采用左冠状动脉前降支结扎法制备大鼠心肌梗死模型,术后6 h经TTC染色法观察并计算心肌梗死体积,经Real-time PCR法检测梗死区心肌组织中Cacna1c、Cacnb2、Ryr2、Serca2a、Ncx1 mRNA表达情况。结果与假手术组不同,模型组大鼠冠脉结扎后ECG可见明显的S-T段改变,且伴有不同程度的心律失常。模型组大鼠心肌梗死体积为(38.36±8.59)%,显著高于假手术组。与假手术组相比,模型组大鼠心肌L型钙通道α1,β亚单位mRNA表达水平差异无统计学意义(P〉0.05),而Ryr2、Serca2a、Ncx1 mRNA的表达均显著减少(P〈0.05,P〈0.01)。结论钙离子调控相关基因Ryr2、Serca2a、Ncx1在大鼠急性心肌梗死中扮演重要角色,其表达异常可能是导致梗死后心肌收缩和舒张功能障碍的机制之一。
Objective To investigate the changes of expression of Ca2+ handling related genes in rats with acute myocardial infarction ( A- MI), including L-type Ca^2+ channel α 1, β subunit (Cacnalc, Caenb2), ryanodine receptor 2 (Ryr2), sarco/endoplamic reticulum Ca^2+-ATPase 2a (Serea2a), and Na^+/Ca^2+ exchanger 1 (Ncxl). Methods Rat modds with myocardial infarction were induced by ligation of the left anterior descending coronary arteries. Infarct size was detected by TFC staining 6 hours after ligation, mRNA expression of Cacnalc, Cacnb2, Ryr2,Serca2a and Ncx1 were evaluated by real-time quantitative PCR in affected myocardial tissues. Results After coronary artery liga- tion,S-T segments in ECG were obviously changed accompanied with arrhythmia. Infarct size in AMI group (38.36%±8.59%) was significantly larger than the sham group. Compared with sham group, there was no significant difference in Cacnalc and Cacnb2 mRNA expression; however, Ryr2, Serez2a and Ncx1 mRNA expression was significantly reduced in AMI group (P 〈 0.05, P 〈 0.01 ). Conclusion Calcium handling related genes Ryr2, Serea2a and Ncxl play an important role in acute myocardial infarction of rats, and their abnormal expression might lead to the contractile and diastolic dysfunction after myocardial infarction.