The protective effects of total paeony glycoside on ischemia/reperfusion injury in H9C2 cells via inhibition of the PI3K/Akt signaling pathway

At present, cardiovascular disease is the global leading cause of mortality. Total paeony glycoside (TPG) is a traditional Chinese medicine, which serves a pivotal role in the cardiovascular system. In the present study, the effects and underlying mechanisms of TPG on ischemia/reperfusion (I/R) injury-induced apoptosis of cardiomyocytes were investigated in vitro. Cell Counting kit-8 and flow cytometry were used to assess the viability, reactive oxygen species (ROS) content and apoptosis of H9C2 cells. The activities of lactate dehydrogenase (LDH), malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GPX) were analyzed by commercial detection kits. Reverse transcription-quantitative polymerase chain reaction and western blot analysis were conducted to evaluate the expression levels of various factors. The results demonstrated that the viability of H9C2 cells was not significantly altered in response to various concentrations of TPG. However, following I/R injury, TPG markedly enhanced cell viability in a time- and dose-dependent manner. Furthermore, TPG decreased the rate of apoptosis and ROS levels, and reduced the activities of MDA and LDH. Conversely, TPG increased SOD and GPX activities. In addition, TPG upregulated the expression levels of pro-caspase-3 and B-cell lymphoma2 (Bcl-2), whereas it downregulated cleaved-caspase-3, poly (ADP-ribose) polymerase 1, Bcl-2-associated X protein, phosphorylated (p)-phosphatidylinositol 3 kinase (PI3K) and p-protein kinase B (Akt) expression. Treatment with insulin-like growth factor-1 increased the apoptosis of H9C2 cells, thus suggesting that activation of the PI3K/Akt signaling pathway reversed the protective effects of TPG. Taken together, TPG may suppress I/R-induced apoptosis and oxidative stress of H9C2 cells possibly by inhibiting the PI3K/Akt signaling pathway; such a phenomenon may have a therapeutic effect on cardiovascular disease.