Dextran Sulphate Sodium (dextran_sulphate + sodium)

Distribution by Scientific Domains

Selected Abstracts

Effect of oral iron supplementation on oxidative stress and colonic inflammation in rats with induced colitis

J. Carrier
Background: Iron supplementation may increase disease activity in ulcerative colitis, possibly through the production of reactive oxygen species from the Fenton reaction. Aim: To assess the effects of two doses of oral iron on intestinal inflammation and oxidative stress in experimental colitis. Methods: Colitis was induced in rats by giving 5% dextran sulphate sodium in drinking water for 7 days. First, using a 2 2 factorial design, rats with or without dextran sulphate sodium received the regular diet or a diet containing iron 3%/kg diet. Second, rats with dextran sulphate sodium-induced colitis were supplemented with iron 0.3%/kg diet and compared with rats on dextran sulphate sodium and regular diet. The body weight change, histological scores, colon length, rectal bleeding, plasma and colonic lipid peroxides, colonic glutathione peroxidase and plasma vitamin E and C were measured. Faecal analysis for haem and total, free and ethylenediaminetetra-acetic acid-chelatable iron was also performed. Results: Iron 3% and iron 0.3% increased the activity of dextran sulphate sodium-induced colitis, as demonstrated by higher histological scores, heavier rectal bleeding and further shortening of the colon. This was associated with increased lipid peroxidation and decreased antioxidant vitamins. Faecal iron available to the Fenton reaction was increased in a dose-dependent manner. Conclusions: Iron supplementation taken orally enhanced the activity of dextran sulphate sodium-induced colitis and is associated with an increase in oxidative stress. [source]

Role of inducible nitric oxide synthase in dextran sulphate sodium-induced colitis

Y. Yoshida
Summary Background: Different authors have postulated both toxic and protective effects for nitric oxide (NO) in the pathophysiology of active inflammation. Aim: To examine the role of NO, especially that produced by the inducible form of nitric oxide synthase (iNOS), by investigating the effects of NOS inhibitors and NO donors on inflammation in experimental acute colitis. Methods: Acute colitis was induced in rats by dextran sulphate sodium (DSS). White blood cell counts and levels of thiobarbituric acid reactants in the portal blood were determined, as were histological changes in the colonic mucosa. We then evaluated the effects of NG -nitro- l -arginine methyl ester ( l -NAME), aminoguanidine (AG) and an NO donor on DSS-induced changes in these inflammatory parameters. Results and Conclusions: Inhibition of NO production by either l -NAME or AG worsened DSS-induced inflammation, suggesting a protective role for NO in acute colitis. On the other hand, a NO donor also exaggerated DSS-induced inflammatory parameters, suggesting that acute colitis may be aggravated by either too much or too little NO. These results suggest that medical treatment of ulcerative colitis must aim for maintenance of appropriate NO levels in the intestinal mucosa. [source]

Glial-derived neurotrophic factor regulates intestinal epithelial barrier function and inflammation and is therapeutic for murine colitis,

Dei Kui Zhang
Abstract Although enteric glial cells (EGCs) have been demonstrated to play a key role in maintaining intestinal epithelial barrier integrity, it is not known how EGCs regulate this integrity. We therefore hypothesized that glial-derived neurotrophic factor (GDNF) produced by EGCs might be involved in this regulation. Here we investigated the role of GDNF in regulating epithelial barrier function in vivo. Recombinant adenoviral vectors encoding GDNF (Ad-GDNF) were administered intracolonically in experimental colitis induced by dextran sulphate sodium (DSS). The disease activity index (DAI) and histological score were measured. Epithelial permeability was assayed using Evans blue dye. The anti-apoptotic potency of GDNF in vivo was evaluated. The expression of tumour necrosis factor- , (TNF- ,), interleukin-1, (IL-1,), and myeloperoxidase (MPO) activity were measured by ELISA assay and/or RT-PCR. The expression of ZO-1, Akt, caspase-3, and NF- ,B p65 was analysed by western blot assay. Our results showed that GDNF resulted in a significant reduction in enhanced permeability, inhibited MPO activity, IL-1, and TNF- , expression, and increased ZO-1 and Akt expression. Moreover, GDNF strongly prevented apoptosis in vivo and significantly ameliorated experimental colitis. Our findings indicate that GDNF participates directly in restoring epithelial barrier function in vivo via reduction of increased epithelial permeability and inhibition of mucosal inflammatory response, and is efficacious in DSS-induced colitis. These findings support the notion that EGCs are able to regulate intestinal epithelial barrier integrity indirectly via their release of GDNF in vivo. GDNF is namely an important mediator of the cross-talk between EGCs and mucosal epithelial cells. GDNF may be a useful therapeutic approach to the treatment of inflammatory bowel disease. Copyright 2010 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. [source]