Effect of <i>Bacillus clausii</i> in attenuating symptoms of <scp>DSS</scp>‐induced ulcerative colitis by modulating <scp>NFkB</scp> pathway and oxidative stress in mice

Ulcerative colitis (UC) is a condition characterized by inflammation and ulcer formation in the colon and rectum due to genetic and environmental factors. It is a common condition, with a global prevalence rate exceeding 0.3%. Current treatments have limited efficacy and can cause unwanted side effects, leading to a high recurrence rate and reduced quality of life for patients. This study suggests that Bacillus clausii has a beneficial role in reducing intestinal inflammation and relieving colitis symptoms in mice. The study aimed to examine B. clausii's potential to reduce the progression and pathogenesis of dextran sulphate sodium (DSS)-induced UC. Bacillus clausii was administered to mice as a pre-treatment, post-treatment and adjunct treatment with sulfasalazine for 14 days. The study found that B. clausii effectively reduced the severity of colitis in mice when used preventatively. Administering B. clausii after the onset of colitis also effectively alleviated symptoms. Combining B. clausii with standard sulfasalazine as adjunct therapy was more effective in reducing intestinal inflammation than using a single therapy alone. B. clausii has shown the potential to prevent colon damage and decrease the likelihood and severity of the disease. Immunohistochemistry results revealed a decrease in the expression of pro-inflammatory cytokines such as IL-1β, TNF-α and NFkB in colon tissue. Additionally, mice that received B. clausii showed a significant increase in anti-oxidant levels and improved haematological markers. In conclusion, it must be emphasized that B. clausii possesses the potential to alleviate the symptoms of UC.