MicroRNA-21 mediates the protective role of emulsified isoflurane against myocardial ischemia/reperfusion injury in mice by targeting SPP1

Isoflurane has demonstrated to exert protective impacts against ischemia/reperfusion (I/R) injury in some organs. This research explored the role of emulsified isoflurane (EI) in myocardial I/R injury through the interaction with microRNA-21 (miR-21). The myocardial I/R injury mouse models established by coronary artery ligation were respectively treated with EI, miR-21 mimic/inhibitor or silenced secreted phosphoprotein 1 (SPP1) plasmids. Then, the pathology, fibrosis and cardiomyocyte apoptosis in mouse myocardial tissues were observed. Furthermore, the expression levels of miR-21, SPP1, oxidative stress indices, inflammatory factors and apoptotic proteins in mouse myocardial tissues were determined. The targeting relation between miR-21 and SPP1 was confirmed. MiR-21 was poorly expressed and SPP1 was highly expressed in myocardial I/R injury mice. EI treatment, elevated miR-21, or silenced SPP1 improved cardiac function and suppressed the oxidative stress, myocardial fibrosis, inflammatory reaction and cardiomyocyte apoptosis in myocardial I/R injury mice, thereby reliving the myocardial I/R injury. These therapeutic effects of EI were repressed by miR-21 inhibition. Additionally, SPP1 was targeted by miR-21. Results in our research indicated that miR-21 mediated the therapeutic effect of EI on myocardial I/R injury in mice by targeting SPP1. This study may provide a novel treatment strategy for myocardial I/R injury.

Automated summary

The study revealed that by increasing miR-21 expression or inhibiting SPP1, EI can improve cardiac function and alleviate oxidative stress, myocardial fibrosis, inflammatory response, and cardiomyocyte apoptosis caused by myocardial I/R injury. Inhibition of miR-21, however, suppresses the therapeutic effects of EI.