Multispecies synbiotics alleviate dextran sulfate sodium (DSS)-induced colitis: Effects on clinical scores, intestinal pathology, and plasma biomarkers in male and female mice.

Background: Inflammatory bowel disease (IBD) is characterized by recurrent inflammation of the gastrointestinal tract and has been linked to an imbalance in gut bacteria. Synbiotics, which combine probiotics and prebiotics, are emerging as potential IBD treatments.

Aim: To examine the effects of four synbiotic formulations on intestinal inflammation and peripheral biomarkers in a rodent IBD model of both sexes.

Methods: Colitis was induced in male and female C57BL/6 mice using 1% dextran sulfate sodium (DSS). Concurrently, a non-exposed control group was maintained. Starting on day 4 post-induction, DSS-exposed mice received one of four synbiotic preparations (Synbio1-4 composed of lactic acid bacteria, Bifidobacterium and dietary fibres), an anti-inflammatory drug used to treat IBD (mesalazine), or placebo (water) until day 14. Clinical symptoms and body weight were monitored daily. Blood samples (taken on days -3, 4, and 14, relative to DSS introduction), were used to analyze plasma biomarkers. At the end of the study, intestinal tissues underwent histological and morphological evaluation.

Results: Compared to placebo, the Synbio1-, 2- and 3-treated groups had improved clinical scores by day 14. Synbio1 was the only preparation that led to clinical improvements to scores comparable to those of controls. The Synbio1-and 3-treated groups also demonstrated histological improvements in the colon. Plasma biomarker analyses revealed significant Synbio1-induced changes in plasma IL17A, VEGFD, and TNFRSF11B levels that correlated with improved clinical or histological scores. Sex-stratified analyses revealed that most therapeutic-like effects were more pronounced in females.

Conclusion: Our findings underscore the potential therapeutic benefits of specific synbiotics for IBD management. However, further research is needed to validate these outcomes in human subjects.