Inhibitory effects of Leuconostoc mesenteroides 1RM3 isolated from narezushi on lipopolysaccharide-induced inflammation in RAW264.7 mouse macrophage cells and dextran sodium sulphate-induced inflammatory bowel disease in mice

The anti-inflammatory bowel disease (anti-IBD) activity of Leuconostoc mesenteroides 1RM3 isolated from saba-narezushi, which has known antioxidant properties, was examined by monitoring its immune and anti-inflammatory activities on murine macrophage RAW264.7 and dextran sodium sulphate (DSS)-induced IBD model mice. Heat-killed Ln. mesenteroides 1RM3 cells promoted nitric oxide (NO) generation in intact RAW264.7 cells. Ln. mesenteroides 1RM3 cells suppressed Escherichia coli O111 lipopolysaccharide (LPS)-induced NO generation. This bacterium also significantly protected RAW264.7 cells from cytotoxicity due to exposure to H2O2. In the case of mice administered with drinking water containing 5% (w/v) DSS, Ln. mesenteroides 1RM3 (about 9.7 log CFU/ml) suppressed colon inflammation, atrophy, diarrheal and bloody bowl discharge. These results suggest that Ln. mesenteroides 1RM3 could be used as probiotics to improve IBD.