miRNA Expression Profile and Effect of Wenxin Granule in Rats with Ligation-Induced Myocardial Infarction

miRNAs are small (approximately 22 nucleotides) noncoding RNAs which post-transcriptionally regulate gene expression by binding complementary sequences within messenger RNA transcripts. miRNAs are likely to regulate many complex processes in the body, indeed aberrant expression of various miRNAs has been implicated in numerous disease states. They have been shown to participate in cardiovascular disease pathogenesis including atherosclerosis, coronary artery disease, myocardial infarction (MI), heart failure and cardiac arrhythmias. To investigate the expression profiles of miRNA in MI, left ventricular tissues from 3 MI rats and 3 non-MI rats (control) that were collected for miRNA expression microarray analyses to explore the role of miRNA in the pathogenesis of MI. To assess the pathways predicted to be targeted by differentially expressed miRNAs in MI, we performed pathway analysis using the online DIANA miRPATH tool. The miR-1 and miR-133, the most abundant miRNAs in the heart, were chosen for further validation by the quantitative real-time polymerase chain reaction, and their expression trends were consistent with the microarray data. Additionally, the effect of Wenxin Granule on miR-1 and miR-133 expression was observed in present study. The male Sprague-Dawley (SD) rats weighted 200±20 g, were acquired from Beijing Vital River Laboratory Animal Technology Co., Ltd, (license number SCXK (Beijing) 2012-0001). All rats received humane care in compliance with the Guide for the Care and Use of Laboratory Animals. The study was performed with approval of the Animal Care Committee of Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine. And efforts were made to minimize the number of animals used. The MI Rat Model was established by a direct coronary artery ligation surgery method. Before surgery, the rats were anaesthetized with1% pentobarbital sodium (50mg / kg) intraperitoneally, and a twelve-lead electrocardiogram (ECG) was performed preoperatively. After left thoracotomy, the left anterior descending coronary artery was ligated directly at the location between the pulmonary cone and the left atrial appendage under its origin 2-3mm in model group except the control (sham-operated) group. In the control group, the left anterior descending artery was not occluded. Additional a twelve-lead ECG was performed postoperatively the day after the surgery. Whether the surgery was successful can be judged by Q wave in postoperative ECG, compared with preoperative ECG. Three rats with successful coronary artery ligation surgery were assigned into the model group. Meanwhile, three rats without coronary artery ligation were assigned to the control group. Distilled water was administered to the rats intragastrically for 4 weeks, after which the rats were euthanized and dissected to isolate the heart for the subsequent experiments. Left ventricular samples were obtained for RNA extraction and hybridization on Agilent miRNA Microarrays.