Gypenoside XVII protects against myocardial ischemia and reperfusion injury by inhibiting ER stress–induced mitochondrial injury

BACKGROUND: Effective strategies are dramatically needed to prevent and improve the recovery from myocardial ischemia and reperfusion (I/R) injury. Direct interactions between the mitochondria and endoplasmic reticulum (ER) during heart diseases have been recently investigated. This study was designed to explore the cardioprotective effects of gypenoside XVII (GP-17) against I/R injury. The roles of ER stress, mitochondrial injury, and their crosstalk within I/R injury and in GP-17–induced cardioprotection are also explored. METHODS: Cardiac contractility function was recorded in Langendorff-perfused rat hearts. The effects of GP-17 on mitochondrial function including mitochondrial permeability transition pore opening, reactive oxygen species production, and respiratory function were determined using fluorescence detection kits on mitochondria isolated from the rat hearts. H9c2 cardiomyocytes were used to explore the effects of GP-17 on hypoxia/reoxygenation. RESULTS: We found that GP-17 inhibits myocardial apoptosis, reduces cardiac dysfunction, and improves contractile recovery in rat hearts. Our results also demonstrate that apoptosis induced by I/R is predominantly mediated by ER stress and associated with mitochondrial injury. Moreover, the cardioprotective effects of GP-17 are controlled by the PI3K/AKT and P38 signaling pathways. CONCLUSION: GP-17 inhibits I/R-induced mitochondrial injury by delaying the onset of ER stress through the PI3K/AKT and P38 signaling pathways.