Compound K Inhibits Autophagy-Mediated Apoptosis Through Activation of the PI3K-Akt Signaling Pathway Thus Protecting Against Ischemia/Reperfusion Injury

Abstract

Background/Aims: A series of reports revealed that autophagy and apoptosis exerted detrimental effects on the pathology of cardiac ischemia/reperfusion (I/R) injury. Ginsenoside compound K (CK), a major intestinal metabolite underlying the pharmacological actions of orally administered ginseng, has a protective effect against myocardial I/R injury. However, the molecular mechanisms by which CK protects against I/R injury remain unclear. In this study, we hypothesized that the cardioprotective effects of CK against I/R injury are mediated by inhibiting autophagy/apoptosis-related signaling pathways in H9c2 cardiomyocyte cells. Methods: H9c2 cells were incubated with CK and exposed to I/R. Cell viability and damage was analyzed by MTT and lactate dehydrogenase assays. Reactive oxygen species (ROS) generation, mitochondrial damage, and cell apoptosis were analyzed by flow cytometry and TUNEL staining. The expression of autophagy, apoptosis, and related signaling proteins was analyzed by Western blotting and immunofluorescence staining. Results: CK pretreatment promoted cell viability and attenuated ROS accumulation and intracellular mitochondrial damage induced by I/R injury Moreover, CK reduced autophagy by regulating the formation of phagocytic precursors to autophagosomes and also inhibited apoptosis through a mitochondrial-mediated pathway. Additionally the cardioprotective effect of CK against I/R injury was mainly through the activation of the PI3K-Akt signaling pathway. Conclusions: CK pretreatment inhibits autophagy-mediated apoptosis induced by I/R injury through the activation of the PI3K-Akt signaling pathway, which reveals that CK may be one of the key bioactive ingredients of ginseng for the treatment of myocardial I/R injury.