Baricitinib relieves DSS-induced ulcerative colitis in mice by suppressing the NF-κB and JAK2/STAT3 signalling pathways.

Ulcerative colitis (UC) is a relapsing inflammatory disease with a unique aetiology. The treatment of UC is challenging, and the current clinical therapeutics for colitis have limited efficacy. Thus, finding new and effective treatment options remains urgent. Baricitinib, an inhibitor of Janus kinase (JAK), has been clinically used to treat rheumatoid arthritis (RA). However, its potential effects on UC have not been fully elucidated. In this study, we aimed to explore the effects of baricitinib on UC and its underlying mechanism. Dextran sulphate sodium (DSS)-induced murine model of chronic colitis was used to investigate the intervention efficacy following oral administration of baricitinib. The levels of key cytokines, such as IL-6, IFN-γ and IL-17A, were determined. Moreover, western blotting for IκBα, p-IκBα, JAK2, p-JAK2, STAT3 and p-STAT3 protein expression was performed to investigate the associated signalling pathways. Our findings demonstrated that baricitinib can significantly relieve DSS-induced UC in mice. After baricitinib intervention, IL-6, IFN-γ and IL-17A levels were decreased both in vitro and in vivo. Moreover, the elevated expression levels of p-IκBα, p-JAK2, and p-STAT3 were significantly reduced after treatment. Collectively, these results suggest that baricitinib is a potential therapeutic agent for alleviation of DSS-induced colitis. This study provides a method for subsequent investigations on potential curative drugs development of the for colitis.