A comparative study of the preventative effects exerted by two probiotics,Lactobacillus reuteriandLactobacillus fermentum, in the trinitrobenzenesulfonic acid model of rat colitis

Abstract

The intestinal anti-inflammatory effects of two probiotics isolated from breast milk,Lactobacillus reuteriandL. fermentum, were evaluated and compared in the trinitrobenzenesulfonic acid (TNBS) model of rat colitis. Colitis was induced in rats by intracolonic administration of 10 mg TNBS dissolved in 50 % ethanol (0·25 ml). EitherL. reuteriorL. fermentumwas daily administered orally (5 × 108colony-forming units suspended in 0·5 ml skimmed milk) to each group of rats (n10) for 3 weeks, starting 2 weeks before colitis induction. Colonic damage was evaluated histologically and biochemically, and the colonic luminal contents were used for bacterial studies and for SCFA production. Both probiotics showed intestinal anti-inflammatory effects in this model of experimental colitis, as evidenced histologically and by a significant reduction of colonic myeloperoxidase activity (P < 0·05).L. fermentumsignificantly counteracted the colonic glutathione depletion induced by the inflammatory process. In addition, both probiotics lowered colonic TNFα levels (P < 0·01) and inducible NO synthase expression when compared with non-treated rats; however, the decrease in colonic cyclo-oxygenase-2 expression was only achieved withL. fermentumadministration. Finally, the two probiotics induced the growth of Lactobacilli species in comparison with control colitic rats, but the production of SCFA in colonic contents was only increased whenL. fermentumwas given. In conclusion,L. fermentumcan exert beneficial immunomodulatory properties in inflammatory bowel disease, being more effective thanL. reuteri, a probiotic with reputed efficacy in promoting beneficial effects on human health.