N-acetylcysteine prevents glucose/glucose oxidase-induced oxidative stress, mitochondrial damage and apoptosis in H9c2 cells

Aims: High blood glucose may auto-oxidize and generate free radicals, which are proposed to induce apoptosis in cardiac cells. The aim of the present study was to investigate the cell damage induced by glucose/glucose oxidase-dependent oxidative stress and the protective effect of N-acetylcysteine (NAC) on H9c2 cardiac muscle cells. Main methods: H9c2 cells were exposed to 33 mM glucose (G)+1.6 milliunits (mU) of glucose oxidase (GO) and termed G/GO. Cell apoptosis, generation of reactive oxygen species (ROS-super oxide anion and hydrogen peroxide) and reactive nitrogen species (RNS-peroxinitrite), and the change in mitochondrial membrane potential (Delta psi m) was studied using flow cytometry and confocal microscopy, and cytochrome c release was measured using confocal microscopy. The expression of Bcl-2, Bax and the activation of procaspase-9 was studied by western blot. Key findings: Exposure of H9c2 cells to G/GO resulted in a significant increase in cellular apoptosis (P<0.05) and the generation of ROS and RNS (P<0.001). Further, G/GO treatment led to a decrease in Delta psi m, release of cytochrome c, decrease in Bcl-2, increase in Bax expression and the activation of procaspase-9. Treatment with NAC significantly decreased apoptosis (P<0.05) and reduced the levels of ROS and RNS (P<0.001). NAC was also able to normalize Delta psi m, inhibit cytochrome c release, increase Bcl-2 and decrease Bax expression and procaspase-9 activation. Significance: Our studies suggest that NAC has antioxidative and antiapoptotic activity against G/GO-induced oxidative stress through the inhibition of mitochondrial damage in H9c2 cells. (C) 2008 Elsevier Inc. All rights reserved.