This study sought to test whether grape seed proanthocyanidin extract (GSPE) attenuates exogenous and endogenous oxidant stress induced in chick cardiomyocytes and whether this cytoprotection is mediated by PKC activation, mito KATP channel opening, NO production, oxidant scavenging, or iron chelating effects. Cells were exposed to hydrogen peroxide (H2O2) (exogenous oxidant stress, 0.5mM) or antimycin A (endogenous oxidant stress, 100μM) for 2h following pretreatment with GSPE at various concentrations for 2h. Cells were also pretreated with GSPE or with inhibitors of PKC (chelerytherine), mito KATP channel (5-hydroxydecanoate), nitric oxide synthase (nitro-L-arginine methyl ester) for 2h. Oxidant stress was measured by 2′,7′-dichlorofluorescin diacetate and cell viability was assessed using propidium iodide. Free radical scavenging and iron chelating ability was tested in vitro. GSPE dose-dependently attenuated oxidant formation and significantly improved cell survival and contractile function. However, inhibitors of PKC, mito KATP channel or NO synthase failed to abolish the protective action of GSPE during H2O2 or antimycin A exposure. In vitro studies suggested that GSPE scavenges H2O2, hydroxyl radical and superoxide, and may chelate iron. These results indicate that GSPE confers cardioprotection against exogenous H2O2- or antimycin A-induced oxidant injury. Its effect does not require PKC, mito KATP channel, or NO synthase, presumably because it acts by reactive oxygen species scavenging and iron chelating directly.
- 2′,7′-Dichlorofluorescin diacetate
- Antimycin A
- Grape seed proanthocyanidin extract
- Hydrogen peroxide
- Propidium iodide
ASJC Scopus subject areas