Herbal formula Xinshuitong capsule exerts its cardioprotective effects via mitochondria in the hypoxia-reoxygenated human cardiomyocytes

Background: The collapse of mitochondrial membrane potential (Delta psi m) resulted in the cell apoptosis and heart failure. Xinshuitong Capsule (XST) could ameliorate left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) classes and the quality of life in patients with chronic heart failure in our clinical study, however, its cardioprotective mechanisms remain unclear. Methods: Primary human cardiomyocytes were subjected to hypoxia-reoxygenation and treated with XST200, 400 and 600 mu g/ml. The model group was free of XST and the control group was cultured in normal conditions. Cell viability,Delta psi m, the activity of mitochondrial respiratory chain complexes, ATPase activity, reactive oxygen species (ROS) and apoptosis cells were determined in all the groups. Results: The cell viability in the XST-treated groups was significantly higher than that in the model group (P < 0.05). Coupled with the restoration of the Delta psi m, the number of polarized cells increased dose dependently in the XST-treated groups. XST also restored the lost activities of mitochondrial respiratory chain complexes I-IV induced by the oxidative stress. The total of mitochondrial ATPase activity was significantly elevated at XST400 and 600 mu g/ml compared to the model group (P < 0.05). The levels of mitochondrial ROS and the number of apoptosis cells declined in the XST-treated groups compared to those in the model group (P < 0.05). Conclusions: XST, via restoration of Delta psi m and the mitochondrial respiratory chain complexes I-IV activities, and suppression of mitochondrial ROS generation and the apoptosis cells, maintained the integrity of the mitochondrial membrane to exert its cardioprotective effects in the hypoxia-reoxygenated human cardiomyocytes.