Therapeutic effect of Streptococcus thermophilus CRL 1190-fermented milk on chronic gastritis

Abstract

Aim: To investigate the potential therapeutic effect of exopolysaccharide (EPS)-producing Streptococcus thermophilus (S. thermophilus) CRL 1190 fermented milk on chronic gastritis in Balb/c mice.

Methods: Balb/c mice were fed with the fermented milk for 7 d after inducing gastritis with acetyl-salicylic acid (ASA, 400 mg/kg body weight per day for 10 d). Omeprazole was included in this study as a positive therapeutic control. The gastric inflammatory activity was evaluated from gastric histology and inflammation score, number of interleukin-10 (IL-10), interferon-gamma (INFgamma) and tumor necrosis factor-alpha (TNF-alpha) cytokine-producing cells in the gastric mucosa, and thickness of the mucus layer.

Results: Animals receiving treatment with the EPS-producing S. thermophilus CRL 1190 fermented milk showed a conserved gastric mucosa structure similar to that of healthy animals. Inflammation scores of the fermented milk-treated mice were lower than those of mice in the gastritis group (0.2 + or - 0.03 vs 2.0 + or - 0.6, P < 0.05). A marked decrease in INFgamma(+) (15 + or - 1.0 vs 28 + or - 1.2, P < 0.05) and TNF-alpha(+) (16 + or - 3.0 vs 33 + or - 3.0, P < 0.05) cells and an increase in IL-10(+) (28 + or - 1.5 vs 14 + or - 1.3, P < 0.05) cells compared to the gastritis group, was observed. Also, an increase in the thickness of the mucus gel layer (2.2 + or - 0.6 vs 1.0 + or - 0.3; 5.1 + or - 0.8 vs 1.5 + or - 0.4 in the corpus and antrum mucosa, respectively, P < 0.05) compared with the gastritis group was noted. A milk suspension of the purified EPS from S. thermophilus CRL1190 was also effective as therapy for gastritis.

Conclusion: This study suggests that fermented milk with S. thermophilus CRL 1190 and/or its EPS could be used in novel functional foods as an alternative natural therapy for chronic gastritis induced by ASA.

Figure 1

Histological micrographs of mice stomachs. A: H (Healthy) group; B: G (Gastritis) group; C: FM 1190 group (fermented milk with Streptococcus thermophilus CRL 1190); D: OM (omeprazole) group; E: M (Milk) group; F: W (Water) group; G: M-EPS 1190 group (EPS produced by S. thermophilus CRL 1190 resuspended in milk) showed conserved histological structures; and H: W-EPS 1190 group (EPS produced by Strep. thermophilus CRL 1190 resuspended in water) displayed chronic inflammatory infiltrations in the mucosa surface (Hematoxylin & eosin, light microscope, × 100).

Figure 2

Inflammation score of stomachs in different groups (mean ± SD).

Figure 3

Number of (A) IL-10-, (B) INF-γ- and (C) TNF-α-producing cells on histological slices of stomachs of mice of different groups. Results are presented as means of 3 determinations and are expressed as the number of IL-10-, INF-γ- and TNF-α-producing cells per 10 fields (magnification × 100). ^aP < 0.05 compared to the controls.

Figure 4

Periodic acid-Schiff (PAS)-positive mucus on the mice gastric mucosa. A: Thickness ratio of the mucus gel layer to the lamina propria mucosa in corpus and antrum mucosa. B: Representative photomicrographs of corpus mucosa from the various groups. Sections were stained using PAS reagent. Values represent mean ± SE of the mean for 5 mice. ^aP < 0.05 compared to the healthy group (H), ^bP < 0.05 compared to the gastritis group (G). Original magnification: × 400. Arrows indicate thickness of mucus layer.