Effects of B acillus subtilis B 10 spores on viability and biological functions of murine macrophages

This study was conducted to investigate the effects of B acillus subtilis   B 10 spores on the viability and biological functions of murine macrophage. RAW 264.7 cells were stimulated both with and without B . subtilis   B 10 spores for 12 h. Then cell viability was determined to evaluate the cytotoxic effect of B . subtilis   B 10 spores to the cells, and the activities of acid phosphatase ( ACP ) and lactate dehydrogenase ( LDH ), the production of nitric oxide ( NO ) and inducible nitric oxide synthase ( iNOS ), and the secretion of inflammatory cytokines were measured to analyze the functions of macrophages. The results showed that B . subtilis   B 10 spores were not harmful to RAW 264.7 cells and they also strongly enhanced the activities of ACP and LDH ( P   <   0.01), remarkably increased NO and iNOS production ( P   <   0.01), and significantly stimulated the secretion of pro‐inflammatory cytokines, including tumor necrosis factor‐alpha ( TNF ‐α), interferon‐gamma ( IFN ‐γ), interleukin‐1 beta ( IL ‐1β), IL ‐6, IL ‐8 and IL ‐12 ( P   <   0.01) while they reduced anti‐inflammatory cytokine IL ‐10 ( P   <   0.01). The outcomes suggest that B . subtilis   B 10 spores are not only safe for murine macrophages, but also can activate these cells and enhance their immune function. The above findings suggest that B . subtilis   B 10 spores are potentially probiotic.