A new mode of probiotic therapy: Specific targeting

• Luminal bacteria are inducers of inflammatory bowel disease.
• Rectal probiotics in colitis altered mucin and TLR mRNA expression close to control.
• Rectal probiotics almost eradicated tissue damage and were superior to oral route.
• Targeted introduction can increase the effect of probiotics.

Luminal bacteria are the most probable inducers of inflammatory bowel disease (IBD). The intestinal microbiota can be modified by probiotics, which reduce symptoms in IBD, via stimulation of the intestinal immune system. We aimed to evaluate the effects of oral and rectal administration of probiotics, on the morphology, gene expression, and microbial ecology of the colon, in a rat trinitrobenzenesulfonic acid (TNBS) model. Colitis was induced with simultaneous rectal or oral administration of probiotics. Both routes of introduction significantly increased the relative amounts of Lactobacillus spp. Rectal introduction almost eradicated damage to the tissue, while enteral introduction only improved it. Only rectal probiotics significantly decreased myeloperoxidase activity, and altered mucin and Toll-like receptor mRNA expression in the colon, to values close to control. We suggest that targeted introduction should be considered not only for probiotics but also for nutrients such as amino acids and vitamins into the colon and intestine.