MiR-808 inhibits cardiomyocyte apoptosis and expressions of caspase-3 and caspase-9 in rats with myocardial infarction by regulating TGF-β1 signaling pathway

J.-W. Zhang, T.-Y. Long, W. Pan, Q.-Q. Zhong, Z.-X. Qian, R. Jing

Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart Lung and Blood Vessel Disease, Beijing Key Laboratory of Precision Medicine of Coronary Atherosclerotic Disease, Clinical Center for Coronary Heart Disease, Capital Medical University, Beijing, China. rjing811@gmail.com

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• Cardiology

OBJECTIVE: To investigate the effects of micro ribonucleic acid (miR)-808 on cardiomyocyte apoptosis and expressions of caspase-3 and caspase-9 in rats with myocardial infarction (MI) by regulating the transforming growth factor-β1 (TGF-β1) signaling pathway.

MATERIALS AND METHODS: A total of 24 specific pathogen-free female Sprague-Dawley rats were enrolled and randomly divided into normal group, model group, and miR-808 group, 8 rats in each group. In the model group and miR-808 group, MI model was prepared by ligation of the left anterior descending coronary artery in the rats. The miR-808 group was transfected with miR-808 lentivirus after the model was established. After one week of intervention, the expression of TGF-β1 was detected by reverse transcription-polymerase chain reaction (RT-PCR). The cardiac function of rats was determined by echocardiography. The myocardium of rats was observed by Masson staining. The cardiomyocyte apoptosis of rats was examined by TdT-mediated dUTP-biotin nick end labeling (TUNEL) method. The expression levels of caspase-3 and caspase-9 were detected by Western blotting.

RESULTS: The expression of TGF-β1 mRNA was higher in the model group than that in the normal group (p<0.05), but compared with that in the model group, it was lower in the miR-808 group. The myocardial function and cardiomyocyte survival rate in the miR-808 group was better and higher than those in the model group (p<0.05). The expression levels of caspase-3 and caspase-9 in the miR-808 group were lower than those in the model group (p<0.05).

CONCLUSIONS: MiR-808 can inhibit cardiomyocyte apoptosis in rats with MI by down-regulating TGF-β1 expression and inhibiting the expressions of caspase-3 and caspase-9.

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