Effectiveness of Saccharomyces boulardii in a rat model of colitis

Abstract

Aim: To investigate the effects of Saccharomyces boulardii (S. boulardii) in an experimental rat model of trinitrobenzene sulfonic acid (TNBS)-induced colitis.

Methods: Thirty-two Wistar albino female rats were categorized into five groups. On the first day of the study, 50 mg TNBS was administered via a rectal catheter in order to induce colitis in all rats, except those in the control group. For 14 d, the rats were fed a standard diet, without the administration of any additional supplements to either the control or TNBS groups, in addition to 1 mg/kg per day S. boulardii to the S. boulardii group, 1 mg/kg per day methyl prednisolone (MP) to the MP group. The animals in the S. boulardii + MP group were coadministered these doses of S. boulardii and MP. During the study, weight loss, stool consistency, and the presence of obvious blood in the stool were evaluated, and the disease activity index (DAI) for colitis was recorded. The intestines were examined and colitis was macro- and microscopically scored. The serum and tissue levels of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) were determined, and fungemia was evaluated in the blood samples.

Results: The mean DAI scores for the MP and S. boulardii + MP groups was significantly lower than the TNBS group (3.69 ± 0.61 vs 4.46 ± 0.34, P = 0.018 and 3.77 ± 0.73 vs 4.46 ± 0.34, P = 0.025, respectively). While no significant differences between the TNBS and the S. boulardii or MP groups could be determined in terms of serum NO levels, the level of serum NO in the S. boulardii + MP group was significantly higher than in the TNBS and S. boulardii groups (8.12 ± 4.25 μmol/L vs 3.18 ± 1.19 μmol/L, P = 0.013; 8.12 ± 4.25 μmol/L vs 3.47 ± 1.66 μmol/L, P = 0.012, respectively). The tissue NO levels in the S. boulardii, MP and S. boulardii + MP groups were significantly lower than the TNBS group (16.62 ± 2.27 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.002; 14.66 ± 5.18 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.003; 11.95 ± 2.34 μmol/L vs 29.72 ± 6.10 μmol/L, P = 0.002, respectively). The tissue NO levels in the S. boulardii, MP and S. boulardii + MP groups were similar. The mean serum and tissue TNF-α levels were determined to be 12.97 ± 18.90 pg/mL and 21.75 ± 15.04 pg/mL in the control group, 18.25 ± 15.44 pg/mL and 25.27 ± 11.95 pg/mL in the TNBS group, 20.59 ± 16.15 pg/mL and 24.39 ± 13.06 pg/mL in the S. boulardii group, 9.05 ± 5.13 pg/mL and 24.46 ± 10.85 pg/mL in the MP group, and 13.95 ± 10.17 pg/mL and 24.26 ± 10.37 pg/mL in the S. boulardii + MP group. Significant differences in terms of the levels of serum and tissue TNF-α and the macroscopic and microscopic scores were not found between the groups. S. boulardii fungemia was not observed in any of the rats. However, Candida fungemia was detected in one rat (14%) in the TNBS group, two rats (28%) in the S. boulardii group, three rats (50%) in the MP group, and three rats (42%) in S. boulardii + MP group.

Conclusion: S. boulardii does not demonstrate considerable effects on the DAI, pathological scores, or cytokine levels but does decrease the tissue NO levels.

Keywords: Fungemia; Nitric oxide; Rat; Saccharomyces boulardii; Trinitrobenzene sulfonic acid; Tumor necrosis factor-α.

Figure 1

Daily defecation trends, rectal bleeding scores, disease activity index analyses, macro- and microscopic pathological scores of the experimental groups. A: Daily defecation trends; B: Rectal bleeding scores; C: Disease activity index analyses; The results are shown as the mean ± SD. ^aP = 0.018 between trinitrobenzene sulfonic acid (TNBS) and methyl prednisolone (MP) group; ^cP = 0.025 between TNBS and Saccharomyces boulardii (S. boulardii) and TNBS group; D: Macro- and microscopic pathological scores. The results are shown as the mean ± SD. DAI: Disease activity index.

Figure 2

Serum and tissue nitric oxide and tumor necrosis factor-α levels of the experimental groups. A: Serum and tissue nitric oxide levels; B: Serum and tissue tumor necrosis factor (TNF)-α levels. The results are shown as the mean ± SD. ^aP < 0.05 vs Saccharomyces boulardii (S. boulardii) + methyl prednisolone (MP); ^cP < 0.05 vs trinitrobenzene sulfonic acid (TNBS). NO: Nitric oxide.