Some species of lactic acid bacteria have been shown to be beneficial in inflammatory bowel disease (IBD). In the present study, a strain of lactic acid bacterium (Lactobacillus paracasei LS2) was isolated from the Korean food, kimchi, and was shown to inhibit the development of experimental colitis induced by dextran sulfate sodium (DSS). To investigate the role of LS2 in IBD, mice were fed DSS in drinking water for seven days along with LS2 bacteria which were administered intragastrically to some of the mice, while phosphate-buffered saline (PBS) was administered to others (the controls). The administration of LS2 reduced body weight loss and increased survival, and disease activity indexes (DAI) and histological scores indicated that the severity of colitis was significantly reduced. The production of inflammatory cytokines and myeloperoxidase (MPO) activity also decreased. Flow cytometry analysis showed that the number of Th1 (IFN-γ) population cells was significantly reduced in the LS2-administered mice compared with the controls. The administration of LS2 induced the increase of CD4+FOXP3+ Treg cells, which are responsible for IL-10. Numbers of macrophages (CD11b+ F4/80+), and neutrophils (CD11b+ Gr-1+) among lamina propria lymphocytes (LPL) were also reduced. These results indicate that LS2 has an anti-inflammatory effect and ameliorates DSS-induced colitis.
Keywords: dextran sulfate sodium; inflammatory bowel disease; kimchi; lactic acid bacteria.