Abstract
Irsogladine maleate (2,4-diamino-6-[2,5-dichlorophenyl]-s-triazine maleate; IM), an anti-peptic ulcer drug, may have a protective effect on the gastrointestinal mucosa. This study investigated the effects of IM on spontaneous colitis in interleukin-10 gene-deficient (IL-10−/−) mice. Five-week-old IL-10−/− mice were fed a control diet or one containing 100 ppm of IM for 10 weeks. Colonic tissues were evaluated morphologically and histologically. J774A.1 murine monocyte/macrophage cells were incubated with IM after lipopolysaccharide stimulation. mRNA expression was assessed by quantitative polymerase chain reaction (PCR) and protein concentration by enzyme-linked immunosorbent assay (ELISA). Colonic length, weight, and histological scores clearly demonstrated that spontaneous colitis was prevented in IL-10−/− mice fed a diet containing IM compared with those fed control diet. Levels of tumor necrosis factor-alpha (TNF-α) (−2.5-fold), IL-1β (−5.4), interferon-gamma (IFN-γ) (−4.5), IL-17 (−113.0), IL-12p35 (−21.0), IL-12p40 (−3.4), and IL-23p19 (−4.2) mRNA expression were significantly decreased in the colonic tissues of IM-treated animals, suggesting that oral treatment with IM suppressed the T-helper (Th)1/Th17 immune response in the colonic mucosa. An in vitro study using monocyte/macrophage cells to clarify the pharmacological action of IM indicated that IL-12p40 and IL-23p19 mRNA expression levels were dose-dependently decreased by IM treatment. ELISA showed that IL-12p40 and IL-23 protein secretion were significantly decreased by IM in a dose-dependent manner. Oral treatment with IM prevented spontaneous colitis in IL-10−/− mice by suppressing the colonic mucosal Th1/Th17 immune response through inhibition of IL-12 and -23 production in monocyte/macrophage cells.
