Gastroprotector effect of the exopolysaccharide produced by Streptococcus thermophilus CRL 1190 on chronic gastritis

CECILIA RODRÍGUEZ; MARTA MEDICI; FERNANDA MOZZI; GRACIELA FONT DE VALDEZ

San Miguel de Tucumán, Argentina

Simposio; III Simposio Internacional de Bacterias Lácticas. Segundo Encuentro Red BAL Argentina.; 2009

Centro de Referencia para Lactobacilos

Gastritis is a common disorder where discontinuity in the gastric mucosa is observed. It is caused by several factors such as intensive use of anti-inflammatory drugs (e.g. acetyl-salicylic acid; ASA) producing toxic effects on the gastric epitelial cells with amplification of the inflammatory process by expression of pro-inflammatory cytokines. Streptococcus thermophilus is used as starter culture for the manufacture of fermented products such as yogurt and cheese. Certain S. thermophilus strains are able to produce exopolysaccharides (EPS); these compounds play an important role in the dairy industry by improving the texture and rheology of fermented foods. In addition, EPS have been claimed to display immunostimulatory and anti-ulcer effects in the host. Previously, we demostrated that BALB/c mice fed with a fermented milk with the EPS-producing S. thermophilus CRL 1190 (FM 1190) was efficient in gastritis preventive and therapeutic treatments. The aim of this work was to evaluate whether the EPS produced by S. thermophilus CRL 1190 (EPS1190) was responsible for the antigastritis effect observed. Thus, the EPS 1190 was isolated from 16-h old milk cultures grown at 37°C by using a deproteinization/precipitation technique with trichloroacetic acid and ethanol and purified by dyalisis. BALB/c mice were fed with 4 mg/Kg/d of the EPS suspended in milk (M-EPS 1190) and water (W-EPS 1190) for 7 days before and after gastritis induction with ASA (400 mg/Kg/d during 10 days). The minimal dose of EPS with gastroprotector effect was also determined. The inflammatory level was assayed by histopathology of the gastric mucosa (hematoxylin-eosin), and the number of pro-inflammatory (INF-g+ and TNF-a+) and regulatory (IL-10+) cytokine-producing cells by indirect immunofluorescence. The mucus gel layer thickness and the volume of intramucosal mucus layer were also determined. M-EPS 1190, but not W-EPS 1190, was able to modulate gastritis, displaying similar histological, histochemical and immunological parameters to those of healthy animals and those treated with the FM 1190. No positive effect was obtained at EPS concentrations lower than 4 mg/kg/d. These results indicate that even though the EPS is responsible for the beneficial effect, the interactions between EPS and milk proteins seem to play an important role in the gastroprotection observed.