Myocardial ischemia reperfusion injury (MIRI) is the leading cause of poor prognosis in patients undergoing clinical cardiac surgery. miRNAs are involved in MIRI. However, the effect of miR-760 on MIRI and molecular mechanism have not been revealed. In vivo experiments, twenty rats were randomly divided into two groups (n = 10): Sham group and Ischemia/Reperfusion (I/R) group. In vitro experiments, H9C2 cells were exposed to hypoxia for 6 h, and then reoxygenated to establish hypoxia / reoxygenation (H/R) model. High expression of miR-760 was observed in MIRI rats and H/R-H9C2 cells. Besides, lactate dehydrogenase (LDH) and malonaldehyde (MDA) levels and myocardial infarct size were notably enlarged in MIRI group, suggesting miR-760 may aggravate MIRI. miR-760 low-expression enhanced the inhibitory effect of NaHS on apoptosis of H/R-H9C2 cells as well as the expression of cleaved caspase 3 and cleaved PARP. TargetScan and dual luciferase reporter assay further confirmed the targeting relationship between dual-specificity protein phosphatase (DUSP1) and miR-760. Additionally, miR-760 overexpression and H/R treatment in H9C2 cells inhibited the expression of DUSP1, which further promoted apoptosis. Furthermore, DUSP1 enhanced the protective effect of NaHS on MIRI. Taken together, these findings suggest that miR-760 restrains the protective effect of NaHS against MIRI.

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