Isosteviol sodium protects heart embryonic H9c2 cells against oxidative stress by activating Akt/GSK-3β signaling pathway

Oxidative stress plays a crucial role in pathogenesis of various cardiovascular diseases. Recent studies reported that isosteviol sodium (STVNa) harbor cardioprotective properties. Here, we explore the potential cardioprotective effect of STVNa on H₂ O₂ -induced oxidative stress on heart embryonic H9c2 cardiomyocytes and the underlying mechanism. We have found that STVNa pretreatment improved cell viability, nuclear morphology and prevented LDH release induced by oxidative stress. STVNa pretreatment also reduced production of reactive oxygen species, preserved mitochondrial function, restored biological antioxidant defense systems and prevented cell death. Western blotting analysis revealed that STVNa regulated the mitochondrial related pro- and anti-apoptotic protein (Bax and Bcl-2 respectively) levels, increased phosphorylation of Akt (ser473) and GSK-3β (ser9) and promoted binding between HK-II and mitochondria under the normal or oxidative stress conditions. LY294002, a PI3K inhibitor, abolished cytoprotective effects of STVNa by inhibiting activation of Akt and GSK-3β. Based on these findings, we conclude that STVNa protects H9c2 cells against oxidative stress by activating Akt/GSK-3β signaling pathway, which, in turn, leads to recruitment of HK-II to mitochondria and regulating Bcl2/Bax levels.