Molecular identification for epigallocatechin-3-gallate-mediated antioxidant intervention on the H2O2-induced oxidative stress in H9c2 rat cardiomyoblasts

Background: epigallocatechin-3-gallate (egcg) has been documented for its beneficial effects protecting oxidative stress to cardiac cells. previously,we have shown the egcg-mediated cardiac protection by attenuating reactive oxygen species and cytosolic ca2+ in cardiac cells during oxidative stress and myocardial ischemia. here,we aimed to seek a deeper elucidation of the molecular anti-oxidative capabilities of egcg in an h2o 2-induced oxidative stress model of myocardial ischemia injury using h9c2 rat cardiomyoblasts. results: proteomics analysis was used to determine the differential expression of proteins in h9c2 cells cultured in the conditions of control,400 μm h2o2 exposure for 30 min with and/or without 10 to 20 μm egcg pre-treatment. in this model,eight proteins associated with energy metabolism,mitochondrial electron transfer,redox regulation,signal transduction,and rna binding were identified to take part in egcg-ameliorating h2o2-induced injury in h9c2 cells. h2o2 exposure increased oxidative stress evidenced by increases in reactive oxygen species and cytosolic ca2+ overload,increases in glycolytic protein,α-enolase,decreases in antioxidant protein,peroxiredoxin-4,as well as decreases in mitochondrial proteins,including aldehyde dehydrogenase-2,ornithine aminotransferase,and succinate dehydrogenase ubiquinone flavoprotein subunit. all of these effects were reversed by egcg pre-treatment. in addition,egcg attenuated the h 2o2-induced increases of type ii inositol 3,4-bisphosphate 4-phosphatase and relieved its subsequent inhibition of the downstream signalling for akt and glycogen synthase kinase-3β (gsk-3β)/cyclin d1 in h9c2 cells. pre-treatment with egcg or gsk-3β inhibitor (sb 216763) significantly improved the h2o 2-induced suppression on cell viability,phosphorylation of pakt (s473) and pgsk-3β (s9),and level of cyclin d1 in cells. conclusions: collectively,these findings suggest that egcg blunts the h2o 2-induced oxidative effect on the akt activity through the modulation of pip3 synthesis leading to the subsequent inactivation of gsk-3β mediated cardiac cell injury. © 2014 chen et al.; licensee biomed central ltd.