Inhibition of autophagy by geniposide protects against myocardial ischemia/reperfusion injury.

Geniposide (GP), extracted from a traditional Chinese herb Gardenia jasminoides, has extensive pharmacological effects. But the effects and the potential mechanisms of GP on myocardial ischemia/reperfusion (I/R) injury are poorly understood. In present study, we investigated the effect of GP on myocardial I/R injury in vivo and hypoxia/reoxygenation (H/R) in vitro respectively, and its mechanism. The results showed that GP reduced myocardial infarct size, alleviated acute myocardial injury, improved cardiac function, regulated apoptosis-related proteins and inhibited apoptosis. In vitro experiments revealed that GP enhanced the cell viability, regulated apoptosis-related proteins and prevented cell apoptosis during H/R in H9c2 cells. GP inhibited the expression of autophagy-related proteins and autophagosome accumulation both in vivo and in vitro. The effects of GP were blocked by rapamycin (RAPA) administration. In summary, our results showed that GP protected against myocardial I/R injury and involved inhibition of autophagy, which might be through activating AKT/mTOR signaling pathways.