心梗后心力衰竭SERCA2a基因甲基化的实验研究

Experimental study of heart failure on SERCA2a methylation in rats with CHD

目的探究心梗后心力衰竭大鼠心肌中SERCA2a(SR Ca2+ATPase 2a,肌浆网Ca2+-ATP酶2a)的DNA甲基化水平及干预效果,为防治心力衰竭提供新靶点。方法取大鼠随机分为3组:对照组、实验组(心衰组)和干预组。心衰组:采用结扎大鼠左冠状动脉前降支的方法制作大鼠心梗后2周心力衰竭模型,根据组织颜色、心电图和心脏彩超检查EF≤55%证明心力衰竭模型成功,心衰组和干预组:结扎后2周分别给予腹腔注射生理盐水0.25 m L/(kg·d)和5-杂氮-2'-脱氧胞苷(5-Aza-2'-deoxycytidine,5Azadc)0.25 mg/(kg·d),每隔两天一次,共3次;对照组于前降支留置一松结,不进行结扎。4周后分别提取大鼠左室心肌组织,分别检测各组心肌中SERCA2a的DNA甲基化水平。结果造模之前各组大鼠超声心动图显示心脏结构及其功能无明显差异。4周后,与对照组相比,心衰组和干预组大鼠的左室舒张末期内径(LVEDD)和左室收缩期末期内径(LVESD)增加,而左室射血分数(LVEF)变小,差异有统计学意义(P<0.05)。与心衰组相比,干预组大鼠的LVEDD和LVESD减小,LVEF增加,差异有统计学意义(P<0.05)。SERCA2a甲基化水平:与对照组相比,心衰组和干预组SERCA2a基因启动子区目标序列中的4个Cp G位点甲基化水平显著升高,差异有统计学意义(P<0.05);而与心衰组相比,干预组SERCA2a基因启动子区目标序列中的4个Cp G位点甲基化水平有所降低,差异有统计学意义(P<0.05)。结论 SERCA2a基因启动子区的DNA甲基化在心力衰竭的发病机制中起着一定的作用,对SERCA2a的DNA甲基化进行干预有望成为治疗心力衰竭的一个新方向和新靶点。

Objective To explore the level of DNA methylation on SERCA2a aboat CHD heart failure rats and its intervention, and find a new target in therapy for the prevention heart fail- ure. Methods The rats were randomly divided into three groups： control group, heart failure （ not intervention） group, and the intervention group. The model of CHD heart failure rats was ligated the left anterior descending coronary artery. If myocardial infarction model was success- ful was judged according to the myocardial tissue and ECG, and the survival rats with EF ≤ 55% underwent ultrasonic cardiogram after 4 weeks. The intervention group was intervented by 5-aza-dc 0. 25 mg/（ kg· d） intraperitoneal injection after produced AMI rat model 2 for weeks, one time every two days, and a total of three times. The control group only had a loose knot on the left anterior descending coronary artery without ligation. After Four weeks, each group rats＇ left ventricular myocardial tissues were extracted respectively, and then the level of DNA methylation about sarcoplasmic reticulum Ca^2＋ ATPase2a （SR Ca^2＋ ATPase 2a, SERCA2a） of myocardial tissue extracted above were detected. Results Before manufacted model, the cardiac structure and function of each groups had no significant difference on echo- cardiography display. Four weeks after the myocardial infarction models, compared with the control group, left ventricular end-diastolic diameter （LVEDD） and left ventricular end-systolic diameter （LVESD） were increased in heart failure group and the intervention group, whereas the left ventricular ejection fraction （LVEF） was smaller, and the difference was statistically significant （ P 〈 0.05 ）. Compared with the heart failure group, LVEDD and LVESD were smaller, but LVEF were increased in the intervention group. Compared with the control group, the 4 CpG loci in the target sequence of SERCA2a gene promoter region were significantly methylated in heart failure group and the intervention group, and the difference was statistically significant （P 〈 0. 05）. When compared with heart failure group, the 4 CpG loci in the inter- vention group had fallen than heart failure group. Conclusion The methylation of SERCA2a gene promoter region maybe play a certain role on the pathogenesis of heart failure. Intervention treatment for DNA methylation of SERCA2a can be expected to become a new direction in the treatment of heart failure and targets.