Protective role of microRNA‐374 against myocardial ischemia‐reperfusion injury in mice following thoracic epidural anesthesia by downregulating dystrobrevin alpha‐mediated Notch1 axis

AbstractIschemia‐reperfusion (I/R) injury often leads to myocardial apoptosis and necrosis. Studies have demonstrated the role microRNAs (miRs) played in myocardial I/R injury. Thus, we established a myocardial I/R injury model and a thoracic epidural anesthesia (TEA) model in mice to explore whether microRNA‐374 (miR‐374) affects myocardial I/R injury. We collected myocardial tissues to evaluate whether TEA exerts a protection effect on myocardial tissues. In addition, the levels of miR‐374, dystrobrevin alpha (DTNA), and the statue of the Notch1 axis were detected. Subsequently, cardiomyocytes extracted from TEA mice were treated to regulate their levels of miR‐374 and DTNA. After that, cell viability, cell cycle distribution, and apoptosis of cardiomyocytes were assessed. This was followed by the detection of the myocardial infarction area. The mice models of myocardial I/R injury were associated with poorly expressed miR‐374 and highly expressed DTNA. TEA was found to protect myocardial tissues against myocardial I/R injury by elevating miR‐374 and reducing DTNA. Dual‐luciferase reporter assay validated that DTNA was the target gene of miR‐374. Cardiomyocytes with overexpressed miR‐374 were shown to have downregulated DTNA levels and blocked Notch1 axis. Overexpressed miR‐374 was also found to promote the viability and inhibit the apoptosis of cardiomyocytes, as well as to increase the number of cells arrested in the S phase. In accordance with this, the myocardial infarction area was decreased with the upregulated miR‐347 and downregulated DTNA. Collectively, these results demonstrated that, by inhibiting the activity of DTNA‐mediated Notch1 axis, miR‐374 could protect against myocardial I/R injury in mice after TEA.