Lactobacillus Casei Protects Dextran Sodium Sulfate- or Rapamycin-Induced Colonic Inflammation in the Mouse

Human colon inflammation is associated with changes in the diverse and abundant microorganisms in the gut. As important beneficial microbes, Lactobacillus contributes to the immune responses and intestinal integrity that may alleviate experimental colitis. However, the mechanisms underlying probiotic benefits have not been fully elucidated. The objective of this study was to assess the impact of Lactobacillus casei Zhang (LCZ) intake on immune and chloride ion channel profiles and to examine its association with gut microbial changes in dextran sodium sulfate or rapamycin-challenged mice. Histological evaluation of the colon, levels of colonic myeloperoxidase, serum tumor necrosis factor-α and interleukin-6 were assessed as inflammatory markers and the gut microbiota profiles of each mouse were studied. We found that LCZ can prevent experimental colitis and rapamycin-induced inflammation in intestinal mucosa by improving histological scores, decreasing host inflammatory cytokines, modulating gut-dominated bacteria, enhancing cystic fibrosis transmembrane conductance regulator expression and blocking interleukin-6 /p-STAT3 or Akt/NF-κB signaling. Our results suggest that LCZ may provide effective prevention against colitis. Funding Statement: Financial support for this research was provided by the National Natural Science Foundation of China (31720103911 and 31622043). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: All animal protocols were approved by the Institutional Animal Care and Use Committee of the Third Military Medical University.