Effects of the probiotic formulation VSL#3 on colitis in weanling rats

Background: Only a few studies have used models of inflammatory bowel disease (IBD) with weanling animals. Previously, the effects of probiotics have not been assessed in such IBD models. The objectives of our study were 2-fold: to establish a suitable model of dextran sulfate sodium (DSS)induced colitis in weanling rats and to determine the effects of the probiotic formulation VSL#3 on DSS-induced colitis in weanling animals. Materials and Methods: Rats were weaned on postnatal day 21 and administered 2%, 2.5%, or 3% (wt/vol) DSS in drinking water. In subsequent experiments, newly weaned animals were administered vehicle or VSL#3 (0.06, 0.6, or 6 mg) by orogastric gavage. These treatments were given to animals maintained on water (postnatal days 21-28) and then on DSS (postnatal days 28-35). Disease activity indices were determined on a routine basis. On day 35, rats were euthanized. The total colon length was determined. Other parameters of colitis were measured from the distal colon. These parameters included myeloperoxidase (MPO), interleukin (IL)-1 beta, inhibitory kappa B-alpha (I kappa B-alpha, and histological assessment of crypt damage and inflammation. Results: DSS 2% was optimal for inducing colitis in weanling rats without significant morbidity. VSL#3 treatments improved various parameters of 2% DSS-induced colitis in weanling rats. The 0.6- and 6-mg doses of VSL#3 were most effective for attenuating this colitis. Conclusions: The probiotic formulation VSL#3 improved DSS-induced colitis in weanling rats. This improvement of colitis involved changes in colonic I kappa B-alpha, IL-1 beta, and MPO, which are suggestive of immune modulation by VSL#3.