Ginsenoside Rb1 pretreatment attenuates myocardial ischemia by reducing calcium/calmodulin-dependent protein kinase II-medicated calcium release

Objective: The aim of this study was to investigate the protective effects of ginsenoside Rb1 and assess whether these protective effects are related to calcium/calmodulin-dependent protein kinase II (CaMKII).Methods: A myocardial ischemia (IS) rat. model and a myocardial H9C2 cell hypoxia model were established. MI was induced by occluding the left anterior descending artery for 120 min. Ginsenoside Rb1 (10 mg/kg) was administered 30 min before ischemia induction, and the treatment continued for 7 days. Results: In the rat IS injury model, ginsenoside Rb1 reduced myocardial infarct size, mean left ventricular diastolic pressure, incidence of arrhythmia, and levels of serum creatine kinase, lactate dehydrogenase, and malondialdehyde. However, the mean left ventricular systolic pressure, and maximal rising and falling rates of ventricular pressure (±dp/dtmax) increased. In the myocardial H9C2 cell hypoxia model, ginsenoside Rb1 reduced intracellular calcium concentrations ([Ca2+ ]i) during hypoxia, and markedly reversed the hypoxia-induced decrease in cell survival. Ginsenoside Rb1 was involved in the downregulation of CaMKII and the ryanodine receptor, as well as hypoxia-induced H9C2 cell survival. Conclusion: The findings of the present study suggest that ginsenoside Rb1 attenuates MI injury in rats, partially through the downregulation of CaMKII expression.