Published online Aug 28, 2013. doi: 10.3748/wjg.v19.i32.5347
Revised: June 3, 2013
Accepted: July 18, 2013
Published online: August 28, 2013
AIM: To determine the efficacy profiles of different concentrations of Lactobacillus acidophilus (L. acidophilus) for treating colitis using an experimental murine model.
METHODS: Colitis was established in 64 BALB/c mice by adding 5% dextran sodium sulfate (DSS) to the drinking water and allowing ad libitum access for 7 d. The mice were then randomly divided into the following control and experimental model groups (n = 8 each; day 0): untreated model control; negative-treatment model control (administered gavage of 1 mL/10 g normal saline); experimental-treatment models C4-C8 (administered gavage of 104, 105, 106, 107, or 108 CFU/10 g L. acidophilus, respectively); positive-treatment model control (administration of the anti-inflammatory agent prednisone acetate at 45 μg/10 g). Eight mice given regular water (no DSS) and no subsequent treatments served as the normal control group. Body weight, fecal traits, and presence of fecal occult blood were assessed daily. All animals were sacrificed on post-treatment day 7 to measure colonic length, perform histological scoring, and quantify the major bacteria in the proximal and distal colon. Intergroup differences were determined by one-way ANOVA and post-hoc Student-Newman-Keuls comparison.
RESULTS: All treatments (L. acidophilus and prednisone acetate) protected against colitis-induced weight loss (P < 0.05 vs model and normal control groups). The extent of colitis-induced colonic shortening was significantly reduced by all treatments (prednisone acetate > C4 > C5 > C7 > C8 > C6; P < 0.05 vs untreated model group), and the C6 group showed colonic length similar to that of the normal control group (P > 0.05). The C6 group also had the lowest disease activity index scores among the model groups. The bacterial profiles in the proximal colon were similar between all of the experimental-treatment model groups (all P > 0.05). In contrast, the bacterial profile in the distal colon of the C6 group showed the distinctive features (P < 0.05 vs all other experimental-treatment model groups) of Lactobacillus sp. and Bifidobacterium sp. being the most abundant bacteria and Staphylococcus aureus being the least abundant bacteria.
CONCLUSION: The most therapeutically efficacious concentration of L. acidophilus (106 CFU/10 g) may exert its effects by modulating the bacterial profile in the distal colon.
Core tip: Efficacies of the current treatments for ulcerative colitis (UC) are limited by procedure-related complications, poor patient compliance, and high relapse rates. Administration of supplemental probiotics represents a promising new therapy of UC. Since UC pathogenic sites mainly involve the rectum and colon and UC patients show differential composition profiles of intestinal bacteria, this study was designed to evaluate the therapeutic efficacies of various concentrations for the standard probiotic, Lactobacillus acidophilus, using a well-known murine model of experimental colitis to examine the changes in colitis symptoms and the corresponding effects on the bacterial flora in the distal and proximal colon.