MiR-204 reduces apoptosis in rats with myocardial infarction by targeting SIRT1/p53 signaling pathway

The aim of this study was to investigate the influence of micro ribonucleic acid (miR)-204 on rats with myocardial infarction by targeting the silent information regulator 1 (SIRT1)/p53 signaling pathway.

A total of 36 Sprague-Dawley rats were randomly divided into three groups, including: sham-operation group (n=12), model group (n=12) and miR-204 mimics group (n=12). The rats in the sham-operation group only underwent thoracotomy, without myocardial infarction injury. Meanwhile, the rats in model group and miR-204 mimics group were utilized to establish the models of myocardial infarction, and then, intervened with normal saline and miR-204 mimics, respectively. The morphology of myocardial tissues was observed via hematoxylin-eosin (HE) staining. Immunofluorescence was performed to detect the expression of Caspase-3. Target genes of miR-204 were analyzed using bioanalysis software. Western blotting (WB) assay was applied to measure the relative protein expression of SIRT1. MiR-204 expression and the messenger RNA (mRNA) expressions of SIRT1 and p53 were measured via quantitative Polymerase Chain Reaction (qPCR). Furthermore, cell apoptosis was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay.

HE staining showed that the morphology of myocardial tissues was normal in sham-operation group. Severe myocardial tissue injury was visible in model group, and the injury was relieved in miR-204 mimics group when compared with model group. The results manifested that the positive expression of Caspase-3 in cardiac tissues increased remarkably in the model group and miR-204 mimics group in comparison with sham-operation group (p<0.05). Meanwhile, it was evidently lower in miR-204 mimics group than model group (p<0.05). Based on the analysis via bioanalysis software, SIRT1 was the target gene of miR-204. WB results revealed that the relative protein expression level of SIRT1 was elevated notably in the other two groups compared with the 2sham-operation group (p<0.05). However, it was markedly lowered in miR-204 mimics group in contrast with model group (p<0.05). QRT-PCR results demonstrated that the model group and miR-204 mimics group exhibited distinctly lower expression of miR-204 but higher mRNA expressions of SIRT1 and p53 than sham-operation group (p<0.05). However, miR-204 mimics group exhibited prominently higher expression of miR-204 but lower mRNA expressions of SIRT1 and p53 than model group (p<0.05). Finally, the results of TUNEL assay demonstrated that the apoptosis rate increased remarkably in the model group and miR-204 mimics group when compared with sham-operation group (p<0.05). However, it decreased notably in miR-204 mimics group in comparison with model group (p<0.05).

MiR-204 reduces the apoptosis level in rats with myocardial infarction via targeted inhibition of the SIRT1/p53 signaling pathway.