Adhesion of Streptococcus thermophillus CRL 1190 to the gastric mucosa in mice detected by scanning electron microscopy

MARCIAL G.; RODRÍGUEZ C.; MÉDICI M.; MOZZI F.; FONT DE VALDEZ, G.

Egmond aan Zee

Simposio; X SIMPOSIUM ON LACTIC ACID BACTERIA; 2011

FEMS

Fermented milk with Streptococcus thermophillus CRL 1190 (FM-1190) has been tested in an in vivo model of active and superficial chronic gastritis induced by acetylsalicylic acid (ASP) in BALB/c mice. Therapeutic and preventive treatments with FM-1190 reduced the lesion on gastric mucosa after 10-d treatment. Histological slides of the treated animals were similar to control mice (without gastritis induction); the former group also displayed increase in IL-10, decrease in TNF-α, and a greater production of mucus. These effects were associated to the exo-polysaccharide (EPS-1190) produced by the strain. Interactions of S. thermophillus CRL 1190 with the gastric mucosal epithelial was addressed in this study. Balb/C mice received FM-1190 during 7d (preventive treatment) followed by 10d ASP administration. Control groups received different treatments: A)- the strain CRL 1190 (without EPS) suspended in milk ; B)- similar to A but the cells suspended in phosphate-buffer saline (PBS). A third group (group C) received no treatment. All groups had free access to conventional balanced diet and water ad libitum. Scanning electron microscopy revealed that the strain CRL 1190 remained attached to the gastric mucosal 10d after ending the treatment (FM-1190 feeding). In contrast, no bacterial cells were observed in the gastric mucosal in any of the control groups (A, B or C). The hypothesis is, that EPS-1190 together with milk proteins creates a microenvironment that allows the probiotic S. thermophillus CRL 1190 to attach to the gastric mucus and to resist under the stress conditions of the gastric environment. Studies are being conducted to confirm this statement.