Lactobacillus casei ATCC 393 combined with vasoactive intestinal peptide alleviates dextran sodium sulfate-induced ulcerative colitis in C57BL/6 mice via NF-κB and Nrf2 signaling pathways

Ulcerative colitis (UC) is an inflammatory bowel disease (IBD) which is related to an immunological imbalance of the intestinal mucosa. Many clinical evidences indicate probiotics supplementation appears to be effective and safe in patients with UC. Vasoactive intestinal peptide (VIP) is an endogenous neuropeptide with multiple physiological and pathological effects. In this study, we investigated the protective effect of the combination of Lactobacillus casei ATCC 393 (L. casei ATCC 393) with VIP on dextran sodium sulfate (DSS)-induced UC in mice and the potential mechanism. The results showed that, compared with the control group, DSS treatment significantly shortened the colon length, caused inflammation and oxidative stress, and further resulted in the intestinal barrier dysfunction and gut microbiota dysbiosis. In addition, intervention with L. casei ATCC 393, VIP or L. casei ATCC 393 combined with VIP significantly reduced UC disease activity index. However, compared with L. casei ATCC 393 or VIP, L. casei ATCC 393 combined with VIP effectively relieved symptoms of UC by regulating immune response, enhancing antioxidant capacity, and regulating nuclear factor kappa-B (NF-κB) and nuclear factor erythroid-derived-2-like 2 (Nrf2) signaling pathways. In conclusion, this study suggests that L. casei ATCC 393 combined with VIP can effectively relieve DSS-induced UC, which is a promising treatment strategy for UC.