α-Cyperone Antagonizes Intestinal Mucosal Inflammatory Response Through Modulation of TLR4/NF-κB Signaling Pathway to Alleviate Crohn's Disease-Like Colitis in Mice

Objective To investigate the effect and potential mechanisms of α-cyperone (CYP) on Crohn's disease (CD) -like colitis induced by 2, 4, 6-trinitrobenzene sulfonic acid (TNBS) in mice.

Methods The mice were randomly and evenly divided into wild type (WT), TNBS, CYP and 5-aminosalicylic acid (5-ASA) groups, with 10 mice in each group. The symptoms of enteritis, the function and structure of the intestinal barrier, and the expression levels of inflammatory factors, including interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and gamma-interferon (IFN-γ), in the colon were assessed. The lipopolysaccharide (LPS)-induced inflammation model of Caco2 cells was constructed and the cells were divided into Control, LPS and LPS+CYP groups. The expression levels of tight junction protein and inflammatory factors in each group were assessed. Gene Ontology (GO) functional enrichment analysis was conducted to predict the possible pathways of action and potential molecular mechanisms of CYP, and to verify them in vivo and in vitro.

Results In the in vivo study, compared with those of the TNBS group, the body mass and colon length of mice in the CYP group and the 5-ASA group were significantly increased, while the disease activity scores and histological inflammation scores were significantly decreased (P<0.05). The level of lucifcein-glucan isothiocyanate and the bacterial translocation rate (in the liver, the spleen, and mesenteric lymph nodes) were significantly decreased, while the transepithelial electric resistance (TEER) value and the expression levels of zonula occluden protein-1 (ZO-1), and claudin-1 were significantly increased (P<0.05). The expression of inflammatory factors was significantly decreased (P<0.05). In the in vitro study, compared with those of the LPS group, the TEER value and the expression of ZO-1 and claudin-1 in the Caco2 cells in the LPS+CYP group were significantly increased (P<0.05). The expression of inflammatory factors was significantly decreased (P<0.05). Enrichment analysis showed that CYP was correlated with inflammatory response (P<0.001). Western blot results showed that CYP could significantly reduce the expression of key proteins in toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) signaling pathway in vivo and in vitro (P<0.05).

Conclusion CYP may protect the intestinal barrier by antagonizing the inflammatory response of the intestinal mucosa through regulating the expression of the TLR4/NF-κB signaling pathway, thereby alleviating TNBS-induced CD-like colitis in mice.