Objective:To investigate the protective action of tanshinone IIA (TSN) on myocardial apoptosis induced by hydrogen peroxide (H2O2) and its effect on prohibitin (PHB) expression to probe the role of PHB in the oxidation stress of myocardial cells. Methods: Primary cultured neonate rat myocardial cells were cultured with TSN (1×10-4 mol/L) for 24 hours, and then the medium was supplemented with 200 μmol/L hydrogen peroxide for 2 h to initiate myocardial cell oxidative stress injury. PHB in myocardial cells was knocked down by small interfering RNA (siRNA), and the expression level of PHB was determined by western blot analysis. Flow cytometry was used to detect the apoptosis rate, intracellular calcium ion concentration ([Ca2+]i) and mitochondrial membrane potential (MMP). Results: The PHB expression, [Ca2+]i and the apoptotic rate significantly increased, and the MMP significantly decreased in the oxidative stress group compared with the control. The PHB expression, apoptosis rate and [Ca2+]i decreased, and MMP increased significantly in the TSN group compared with the oxidative stress group. Compared with the siRNA negative control group, the PHB expression level in myocardial cells was down-regulated, and the apoptosis rate and [Ca2+]i increased, and MMP decreased significantly in the siRNA group. Conclusion: TSN can reduce PHB expression in oxidative stress-injured myocardial cells hence protecting the myocardial cells.
