Anti-inflammatory effect of miltirone on inflammatory bowel disease via TLR4/NF-κB/IQGAP2 signaling pathway

Inflammatory bowel disease (IBD) is characterized by a radical imbalance in the activation of proinflammatory and anti-inflammatory signaling pathways in the gut. This study was conducted to evaluate the anti-inflammation effect of miltirone against IBD in vitro and in vivo, and try to explore the underlying mechanisms. Miltirone could extenuate the loss of colon length and weight caused by TNBS. Additionally, macroscopic scores and DAI were reduced significantly compared with the TNBS group. The levels of TNF-alpha, IL-1 beta, IL-6 and IL-8 were increased significantly with the induction by TNBS (100 mg/kg) or LPS (0.5 mg/mL). Interestingly, miltirone could down-regulate the levels of these increased proinflammatory factors in a dose-dependent manner both in vivo and in vitro. The protein and mRNA expressions of TLR4, MyD88, NF-kappa B p65 were up-regulated by TNBS or LPS stimulation. CRX-526, the TLR4 inhibitor, as well as miltirone could significantly suppress the increased protein and mRNA expressions. Miltirone could up-regulate the descreased IQGAP2 expression induced by LPS. All these revealed that the anti-inflammatory effect of miltirone on IBD may be via regulating TLR4/NF-kappa B/IQGAP2 signaling pathway. The findings might supply beneficial hints for the drug research to cure the IBD. (C) 2016 Elsevier Masson SAS. All rights reserved.