spores maintain gut homeostasis in murine ulcerative colitis via modulating microbiota, apoptosis, and the TXNIP/NLRP3 inflammasome cascade.

Ulcerative colitis (UC), a persistent immune-mediated disorder lacking effective treatment, is distinguished by gut microbiota dysbiosis, abnormal activation of the NLRP3 inflammasome pathway, and apoptosis. Despite growing attention to these factors, understanding their significance in UC pathogenesis remains a challenge. The present study explores the potential therapeutic impact of (Bc) spores in a murine UC model induced by drinking 4 % (w/v) dextran sulfate sodium (DSS) in C57BL/6 mice. Subsequently, the DSS-induced mice were orally administered either Bc at varying concentrations (10 and 10 Colony forming unit, CFU) or sulfasalazine (SSZ) at a dosage of 200 mg/kg for 7 days. The disease-specific activity index (DAI) was calculated daily utilizing parameters such as body weight, diarrhea, and bloody stool. Changes in fecal and abundance, colonic TXNIP and NLRP3 contents, as well as colonic caspase-1, IL-1β, Bax, and Bcl-2 expression, were investigated. Additionally, markers related to oxidative stress and inflammation, histopathological changes and caspase-3 immunohistochemistry testing were conducted. DSS-treated mice had significantly higher DAI scores compared to controls, indicating severe colitis. However, SSZ treatment or Bc (10 CFU) dramatically lowered DAI scores, with the highest Bc dosage (10 CFU) producing the greatest improvement. Furthermore, Bc (10 CFU) substantially ( < 0.05) boosted fecal while decreased , indicating reversal of gut dysbiosis. Bc effectively reduced colonic oxidative stress and inflammation by replenishing GSH and catalase and modulating the NF-κB, Nrf2/HO-1, and TXNIP/NLRP3 pathways. Additionally, Bc (10 CFU) exhibited histologically almost normal mucosa, with maintained architecture and reduced apoptosis, as seen by normalization of Bcl2 and Bax with decreased caspase-3. Collectively, these findings point to the potential usefulness of Bc spores in preventing and treating DSS-induced colitis, positioning them as a promising candidate for UC management.