Paeoniflorin ameliorates reperfusion injury in H9C2 cells through SIRT1-PINK1/parkin-mediated mitochondrial autophagy

Myocardial ischemia-reperfusion injury (MIRI) injury is a serious health problem, which can seriously affect the recovery of patients with myocardial infarction and even lead to death. Paeoniflorin (PF) is a potential therapeutic drug to prevent reperfusion injury. However, the mechanism of PF in MIRI is not clear. Compared with other cells, cardiomyocytes have the largest number of mitochondria. Therefore, this study researched the protective mechanism of paeoniflorin pretreatment on myocardial ischemia-reperfusion injury (AMI) from the perspective of mitochondrial autophagy. Paeoniflorin was given or not given to H9C2 cells 12 h before reperfusion. Pretreatment of paeoniflorin can significantly increase the viability of H9C2 cells and inhibit the increase of ROS secretion induced by OGD/R. The increase of MDC autophagy fluorescence and mitochondrial membrane potential (MMP) suggested that the myocardial protective effect of paeoniflorin may also be related to mitochondrial autophagy. Next, we detected the related signals in the classical mitochondrial autophagy pathway of PINK1/parkin by Q-PCR and Western blots. The results showed that the pretreatment of paeoniflorin could promote the levels of SIRT1, Beclin1, PINK1, parkin and LC3, inhibit the level of P62. In order to further clarify whether paeoniflorin-induced SIRT1 activation is necessary for autophagy and its potential mechanism, we detected the autophagy level of H9C2 cells with SIRT1 inhibitor (EX527). The results showed that after pretreatment of EX527, the protective effect of paeoniflorin on oxidative damage and autophagy pathway was significantly decreased. The mechanism may relate to SIRT1-PINK1/parkin mitochondrial autophagy pathway. In summary, these results suggested that paeoniflorin may protect H9C2 cells from OGD/R damage by activating SIRT1-PINK1/parkin pathway. This provides new experimental basis for paeoniflorin in the treatment of MIRI.