Cardiac shock wave therapy protects cardiomyocytes from hypoxia-induced injury by modulating miR-210

Cardiac shock wave therapy (SWT) has been described as a novel therapeutic strategy that is able to alleviate myocardial ischemic injury. microRNA (miRNA/miR)-210 plays a cytoprotective role in cardiomyocytes in response to hypoxia by regulating cell apoptosis. The aim of the present study was to investigate whether cardiac SWT could protect cardiomyocytes from hypoxia-induced injury by regulating miR-210 expression. The murine adult cardiomyocyte cell line HL-1 was incubated for 5 h in hypoxic conditions, followed by reoxygenation for 12 h and treatment with SWT immediately following hypoxia in the present study. The cell viability was determined using an MTS assay. Western blot analyses were performed in order to detect cell signaling changes. Reactive oxygen species production was detected using dihydroethidium staining, and malondialdehyde levels were measured using the thiobarbituric acid method. miRNA and mRNA expression levels were confirmed via reverse transcription-quantitative PCR. Apoptosis was evaluated by means of flow cytometry. HL-1 cells were then transfected with miR-210 mimics or inhibitors in order to alter miR-210 expression levels, and the effects on HL-1 cells were determined. Hypoxia led to elevated oxidative stress, enhanced cell apoptosis and upregulated miR-210 expression levels in HL-1 cells, while SWT could alleviate hypoxia-induced cell injury and further promote miR-210 expression. miR-210 overexpression decreased apoptosis and oxidative stress during hypoxic stress in HL-1 cells, whereas inhibition of miR-210 increased cell apoptosis and promoted oxidative stress. Furthermore, miR-210 inhibition could reverse the effects of SWT on HL-1 cells. Finally, the mRNA analysis revealed that SWT significantly attenuated apoptosis-inducing factor mitochondrion-associated 3 and caspase 8 associated protein 2 mRNA expression levels in cardiomyocytes exposed to hypoxia, which were two targets of miR-210. SWT could exert cardioprotective effects against hypoxia-induced cardiac injury by modulating miR-210.