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Primary sclerosing cholangitis is often complicated by ulcerative colitis. Recently, we reported on Th1-dominant cholangitis associated with experimental colitis, and natural killer T (NKT) cells might play an important role in this model. The aim of this study was to clarify the immunopathogenic role of NKT cells in this model using alpha-galactosylceramide. CD-1 mice were administered 2.0% dextran sulfate sodium for 29 days and injection of alpha-galactosylceramide was performed every 5 days, then inflammation was assessed. Mononuclear cells from the liver were analyzed with respect to cytokine production and the surface marker. alpha-Galactosylceramide improved survival rate, weight gain, and inflammation score. Also, interferon-gamma release from MNC, CD4/CD8 ratio, NKT cell population, and NK cell population were decreased by this treatment. These findings indicate that repeated stimulation of NKT cells modifies the Th1/Th2 balance to reduce Th1 dominance, and this may be a mechanism by which alpha-galactosylceramide has a therapeutic effect.

Primary sclerosing cholangitis is frequently complicated by inflammatory bowel disease. Although many colitis models have been reported, little information has been obtained about complicated cholangitis. The aim of the present study was to determine whether hepatobiliary disorders occur in mice experimental colitis, and to clarify the underlying mechanisms. The CD-1 mice were fed standard chow with or without dextran sulfate sodium in the drinking water, followed by histological examination of the liver and colon. Mononuclear cells were isolated from these organs, and cytokine production was assessed. The CD4/CD8 ratio and the population of natural killer T (NKT) cells were analyzed by flow cytometry. Inflammatory cell infiltration and focal necrosis in the liver were found in 33% of treated mice. In treated mice, the CD4/CD8 ratio increased in the liver, whereas no such change was found in the colon. Also an increase of interferon-γ and a decrease of interleukin-4 production were observed. The NKT cell population showed transient changes in the liver and colon. Hepatobiliary disorders were complicated with experimental colitis in CD-1 mice. Immunological findings indicate a T-helper-1-dominant underlying mechanism, and NKT cells may play a pathogenic role in this model. This model may help to elucidate the relationship between hepatic and colonic inflammations. © 2004 Blackwell Publishing Asia Pty Ltd [ABSTRACT FROM AUTHOR]