Anti-ulcer effects of lactic acid bacteria and their cell wall polysaccharides.

The anti-ulcer effects of bifidobacteria, lactobacilli and streptococci were examined using the acetic acid-induced gastric ulcer and ethanol-induced erosion models in rats. Bifidobacterium breve YIT4014 and 4043, and Bifidobacterium bifidum YIT4007 were administered orally, and anti-ulcer effects were confirmed for not only these organisms but also their polysaccharide fractions (PSFs). The major component of these anti-ulcer polysaccharides was rhamnose. In particular, polysaccharides in which the rhamnose content exceeded 60% were more effective in healing gastric ulcers. After administration of the PSF from B. bifidum YIT4007, the levels of epidermal growth factor and basic fibroblast growth factor increased in gastric tissues. Similar results were observed for the culture supernatant of gastric epithelial cells cultured with PSF. Furthermore, the production of 6-ketoprostaglandin F1 alpha by macrophages was also enhanced by PSF. These results indicated that these bacteria and their polysaccharides induced host repair and protective systems in the gastric ulcer model.