Examining miR-196a, miR-196b and NF-κBIα gene expression in colitis mice model.

Bifidobacterium bifidum (B. bifidum) anti-inflammatory characteristics and ability to modify the gut microbiota make it a promising treatment option for Inflammatory Bowel Disease (IBD). The present study investigated the modulatory effects of B. bifidum on the expression of miR-196a, miR-196b, and NF-κBIα genes in a DSS-induced IBD mice model. Thirty male C57BL/6 mice were randomly assigned to five experimental groups (G1-G5). The induction of colitis used 3% DSS in drinking water for 8 days. The Disease Activity Index (DAI) was monitored, and mice were euthanized for further analysis on the 22nd day. The mice were gavaged with 2 × 10⁹ CFU/ml of B. bifidum per day. Histological grading of the colon tissues was done, and the levels of cytokines TNF-α and IL-6 were measured using ELISA. At the gene level, the expression of miR-196a, miR-196b, and NF-κBIα was analyzed by RT-PCR. Weight gain from days 11 to 17 in G3 and G4 with B. bifidum treatment pointed out its therapeutic benefits. Colon length, weight, and spleen weight were significantly decreased in G2 compared to G1 (P ≥ 0.0001). Histopathological examination revealed severe mucosal damage in G2, reduced inflammation in G3, fewer deep wounds in G4, and significant healing in G5. B. bifidum, especially in G5, significantly reduced IL-6 and TNF-α levels (P ≥ 0.0002). Gene expression analysis showed decreases in miR-196a and NF-κBIα and an increase in miR-196b, with G5 showing the most changes (P ≥ 0.0001). In conclusion, B. bifidum demonstrated significant anti-inflammatory effects in the DSS-induced IBD model by modulating miRNA expression and reducing key inflammatory cytokines.