Protective effects of ginsenoside Rb2 on myocardial ischemia in vivo and in vitro

Ginsenoside Rb2 is one of the major active components of Panax ginseng. There is little research about cardioprotective effect of ginsenoside Rb2. The aim of this study was to explore the cardioprotective effects of ginsenoside Rb2 on animal model of myocardial ischemia/reperfusion (MI/R) injury in vivo and H2O2-induced stress in H9c2 cells in vitro. Pretreatment with ginsenoside Rb2 (10 and 20 mg/kg) could significantly improve cardiac function, remarkably decrease infarct size from 29.84% to 17.34%, decrease the activities of CK-MB, LDH, and AST in serum. Meanwhile, ginsenoside Rb2 (10 and 20 mg/kg) significantly increased the activities of SOD, CAT and GSH-PX, and decreased the level of MDA in tissue (P < 0.05). Histopathological results demonstrated the protective effect of ginsenoside Rb2. Furthermore, the anti-apoptotic effect of ginsenoside Rb2 was confirmed by the results of TUNEL staining. Western blot analysis demonstrated that ginsenoside Rb2 up-regulated levels of Bcl-2, Procaspase-3, -9 expression and down-regulated level of Bax expression. In vitro, pretreatment with ginsenoside Rb2 (1, 3 and 10 μg/mL) prior to H2O2 exposure could increase cell viability of H9c2 cells. Pretreatment with ginsenoside Rb2 (1, 3 and 10 μg/mL) also increased the activity of SOD, and decreased the level of LDH in the cultured supernatant and the MDA level in H9c2 cells. These results indicated that ginsenoside Rb2 had cardioprotective effects both in vivo and in vitro. The mechanisms involved may be attributed to the scavenging of oxidative stress products, increasing the concentration of antioxidant defense enzymes and inhibiting cardiomyocyte apoptosis.