Protective effect of Bacillus subtilis B10 against hydrogen peroxide-induced oxidative stress in a murine macrophage cell line

The present study was designed to determine, whether Bacillus subtilis B10 could enhance the antioxidant activity of RAW 264.7 cells and attenuate the oxidative stress induced by hydrogen peroxide (H2O2). In addition, the responses were contrasted with a powerful antioxidant, vitamin E. RAW 264.7 cells were pretreated for 12 h with 100 mM vitamin E or B. subtilis B10 (1x10(8) cfu well-1), respectively and consecutively exposed to 500 muM H2O2 for an additional 6 h of incubation. Additional control group was included with exposure to B. subtilis B10 (1x10(8) cfu well-1) in the absence of H2O2. After incubation, cells were collected for further analysis of anti-oxidative indicators. The results showed that, cells pre-treated with B. subtilis B10 manifested remarkable increase in total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD), catalase (CAT), anti-superoxide activity (ASOA), glutathione peroxidase (GPX) as well as glutathione reductase (GR) levels and significant drop in myeloperoxidase (MPO) and malondialdehyde (MDA) content. The activity of inducible NO synthase (iNOS) was also elevated in B. subtilis group, while NO content decreased markedly. Additionally, exposure to H2O2 with prior B. subtilis B10 treatment induced high gene expression levels of glutathione S-transferases (GST) and gamma-glutamylcysteine synthetase (gamma-GCS) in RAW 264.7 cells. However, vitamin E showed a limited protective effect when compared with B. subtilis B10 in our study. The current findings concluded that, B. subtilis B10 protected cells from H2O2 induced oxidative damage, presumably by enhancing enzymatic antioxidant defense systems of RAW264.7 cells.