Inflammatory bowel diseases
Ulcerative colitis (UC) is characterized by chronic digestive track inflammation and immune system malfunction. We investigated the efficacy of different strains of bacteria in an in vivo model of DSS colitis. Stool and body weight were evaluated and a total disease activity index (DAI) was calculated. Colons were collected for histo-pathological evaluation. Bacterial dosing, individually or as a combination of the three strains, was performed daily at 1.5x1010cfu/ml.The same strains were also tested, individually, for their ability to competitively inhibit adhesion and invasion of pathogenic E. coli strains (AIEC and HLMN-1) in a model of gut epithelium (co-culturing Caco-2 and HT29-MTX cells).
When administered separately, lower DAI score was noted for one of the three strains compared to DSS controls during the early phase of the treatment period. No meaningful differences were noted in the length and weight of colon. When administered as a mixture, significantly lower DAI score were noted on Day 5 and lasted until the end of the treatment period. Slight improvements in the length of colon were noted for treated animals compared to DSS controls. Cell culture indicates that all strains competitively inhibited adhesion, invasion and/or translocation of the two pathogenic strains.
Our data clearly indicate treatment of mice with our combination of strains by oral gavage significantly prevents development of DSS-induced colitis in mice with no significant safety concern. These bacterial strains present an alternative approach in treatment of colitis in clinic.