Hydrogen‐rich saline alleviates cardiomyocyte apoptosis by reducing expression of calpain1 via miR‐124‐3p

Abstract Aims Molecular hydrogen has been exhibited a protective function in heart diseases. Our previous study demonstrated that hydrogen‐rich saline (HRS) could scavenge free radicals selectively and alleviate the inflammatory response in the myocardial ischaemia/reperfusion (I/R) injury, but the underlying mechanism has not been fully clarified. Methods and results Adult (10 weeks) C57BL/6 male mice and neonatal rat cardiomyocytes were used to establish I/R and hypoxia/reoxygenation (H/R) injury models. I/R and H/R models were treated with HRS to classify the mechanisms of cardioproctective function. In this study, we found that miR‐124‐3p was significantly decreased in both I/R and H/R models, while it was partially ameliorated by HRS pretreatment. HRS treatment also alleviated ischaemia‐induced apoptotic cell death and increased cell viability during I/R process, whereas silencing expression of miR‐124‐3p abolished this protective effect. In addition, we identified calpain1 as a direct target of miR‐124‐3p, and up‐regulation of miR‐124‐3 produced both activity and expression of calpain1. It was also found that compared with the HRS group, overexpression of calpain1 increased caspase‐3 activities, promoted cleaved‐caspase3 and Bax protein expressions, and correspondingly decreased Bcl‐2, further reducing cell viability. These results illustrated that calpain1 overexpression attenuated protective effect of HRS on cardiomyocytes in H/R model. Conclusions The present study showed a protective effect of HRS on I/R injury, which may be associated with miR‐124‐3p–calpain1 signalling pathway.