Protective effects of miR-34b and miR-337 against myocardial ischemia/reperfusion injury in rats by liposomal nano-delivery system

Abstract

Although a few microRNAs (miRNAs) are involved in the regulation of myocardial ischemia/reperfusion injury (MI/RI), their exact roles in this process, and the mechanisms involved have not been fully elucidated. This study was carried out to investigate the protective effects of miR-34b and miR-337 against MI/RI. For this purpose, 56 Sprague-Dawley (SD) rats were randomly divided into two groups: sham operation group and myocardial MI/RI group, with 28 rats in each group. Then, a rat model of MI/RI was established. Changes in myocardial tissues of the two groups were determined using hematoxylin-Eosin (H&E) staining. Serum level of myocardial troponin c(TnT) was assayed with ELISA method, while myocardial tissue mRNA expressions of miR in the two groups was determined with qRT-PCR. Results showed that the rat model of MI/RI was successfully established, as was evident in myocardial cell necrosis, disorganized myocardial fibers, interstitial edema, and neutrophil infiltration. There were significant increases in serum troponin content and mRNA expression levels of miR-337 and miR-34b in tissues. In conclusion, the expression levels of miR-337 and miR-34b are increased in myocardial tissues of rats with MI/RI. Thus, miR-337 and miR-34b may be involved in the pathogenesis of MI/RI via regulation of NOX4 and Samd7, respectively. Finally, by using liposomal nanocarrier, the therapeutic effect of miR-337 and miR-34b on MI/RI was investigated.