Collagen Peptides and Saccharomyces boulardii CNCM I-745 Attenuate Acetic Acid-Induced Colitis in Rats by Modulating Inflammation and Barrier Permeability

Abstract

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by recurrent episodes of inflammation and tissue damage, with limited treatment options. This study aimed to investigate the effects of collagen peptides and Saccharomyces boulardii on acetic acid (AA)-induced colitis. Thirty-six male Sprague-Dawley rats were randomly divided into the following four groups: normal control (NC), colitis control (CC), collagen peptide (CP; 0.6 g/kg/day), and S. boulardii (SB; 250 mg/day). Colitis was induced by an intrarectal administration of AA in all groups except NC, and treatments were administered daily for 7 days. The therapeutic effects were evaluated by assessing the disease activity index (DAI), colon mass index, macroscopic and microscopic tissue damage, histopathological changes, zonula occludens (ZO)-1 protein expression, and myeloperoxidase (MPO) activity. The results showed that CP and SB treatments substantially alleviated DAI scores (p < 0.05) and reduced the colon mass index. Colon macroscopic and microscopic damages improved compared to the CC group (p < 0.01). Histologically, both treatments reduced inflammatory cell infiltration, crypt damage, and ulceration, with CP showing a slightly more pronounced effect. Immunohistochemical analysis revealed significant restoration of ZO-1 protein expression in the treated groups, indicating improvement in intestinal barrier integrity (p < 0.01). Furthermore, MPO activity was reduced in both CP and SB groups, significantly in the SB group (p < 0.01). These findings are consistent with previous studies that highlight the anti-inflammatory and barrier-enhancing effects of collagen peptides and probiotics in UC models.

Keywords: Saccharomyces boulardii; collagen peptides; inflammation; rat; ulcerative colitis.

FIGURE 1

Timeline of colitis induction and treatments. NC, normal control; CC, colitis control (n = 9); CP, collagen peptide (n = 9); SB, S. boulardii (n = 9); MPO, myeloperoxidase; ZO‐1, zonula occludens‐1.

FIGURE 2

Effects of treatments on (a) changes in body weight, (b) disease activity index, (c) colon mass index, and (d) macroscopic appearance of distal 8 cm colons in colitis rats. CC, colitis control; CP, collagen peptidesNC, normal colitis; SB, S. boulardii. Data are presented as mean ± SD with *p < 0.05 and **p < 0.01 compared to the NC group, #p < 0.05 and ##p < 0.01 compared to the CC group, and p < 0.05 compared to the CP group.

FIGURE 3

Effects of treatments on colon damage in AA‐induced colitis in rats. (a) Colon macroscopic score, (b) microscopic score, (c) ZO‐1 expression level, and (d) MPO activity. NC, normal colitis; CC, colitis control; CP, collagen peptides; SB, S. boulardii; MPO, myeloperoxidase; ZO‐1, zonula occludens‐1. Data are presented as mean ± SD with **p < 0.01 compared to the NC group, and, ## p < 0.01 compared to the CC group.

FIGURE 4

Light microscopic examination of the colon mucosa in the experimental groups. (a) H&E stain. (b) Masson's trichrome stain. (c) PAS stain. The NC group showing a regular morphology of the colon mucosa. The CC group shows extensive ulcer (star), transmural inflammatory cell infiltrates (thick arrow), severe submucosal edema (asterisks), and cyrpt damage with loss of goblet cells (yellow arrow). The CP and SB groups show mild‐to‐moderate changes, including vascular congestion (thin arrow) and mild edema (asterisk), similar to the CC group. All bars are 200 μm. CC, colitis control; CP, collagen peptides; H&E, hematoxylin and eosin; NC, normal colitis; PAS, periodic acid–Schiff; SB, S. boulardii.

FIGURE 5

ZO‐1 immunohistochemical staining image of the representative colon sections from the experimental groups. The NC group showing a strong expression of ZO‐1 in the crypt epithelium. The CC group shows a very weak expression, and the CP and SB groups show a moderate expression of ZO‐1 in the crypt epithelium. All bars are 50 μm. CC, colitis control; CP, collagen peptides; NC, normal colitis; SB, S. boulardii; ZO‐1, zonula occludens.