Experimental colitis induced by dextran sulphate sodium in mice: beneficial effects of sulphasalazine and olsalazine.

BACKGROUND: Animal models of inflammatory bowel disease are artificial and more or less representative of human disease. However, the dextran sulphate sodium (DSS) induced intestinal inflammation model has recently been shown to fulfil some pathological criteria for an adequate experimental model. AIM: To determine whether this form of experimental intestinal inflammation responds to established therapy used for human inflammatory bowel disease. METHODS: DSS was used to induce intestinal inflammation in conventional Balb/c mice and athymic nu/nu CD-1(BR) mice, and the well-documented 5-aminosalicylic acid (5-ASA) based anticolitis drugs sulphasalazine (SASP) and olsalazine (OLZ) were used to study therapeutic effects. Parameters which have been shown to reflect DSS-induced intestinal inflammation (body weight, colon length, spleen weight, diarrhoea, and rectal bleeding) were measured in the Balb/c mice. RESULTS: Significant amelioration was seen on these parameters after different treatment protocols. Survival in nu/nu CD-1 mice was studied, and after 16 days a death rate of 50% was noted in the DSS group. SASP (100 mg/kg/day) and OLZ (50 mg/kg/day) significantly prolonged the survival to 29 and 38 days, respectively. SASP and OLZ showed a dose-dependent effect in the range between 10 and 100 mg/kg/day, doses closely corresponding to those used in humans. CONCLUSIONS: SASP and OLZ are able to ameliorate the DSS-induced intestinal inflammation. The dose-response patterns suggested that the active therapeutic moiety for the two drugs appears to be mainly the liberated 5-ASA molecule.

Dextran sulfate sodium (DSS) induced experimental colitis in immunodeficient mice: effects in CD4(+) -cell depleted, athymic and NK-cell depleted SCID mice.

Administration of dextran sulfate to mice, given in the drinking water results in acute or subacute colonic inflammation, depending on the administration protocol. This colonic inflammation exhibits ulceration, healing and repair, and a therapeutic response that makes it valuable for the study of mechanisms that could act in the pathogenesis of human ulcerative colitis, a disease thought to have an immunologically dependent pathogenesis. To investigate if immunological mechanisms were involved in the induction of colonic inflammation in this model, mice with different degrees of immunodeficiency were used. It was shown that dextran sulfate induced colitis could be induced in Balb/c mice depleted of CD4(+) helper T cells by treatment with monoclonal antibodies preceded by adult thymectomy. The depletion of CD4(+) was verified by flow cytometric analysis. Furthermore, the colonic inflammation could equally be induced in athymic CD-1 nu/nu mice lacking thymus-derived T cells, in T and B-cell deficient SCID mice, and also in SCID mice depleted of NK cells by treatment with anti-asialo GM1 antibodies. The NK-cell depletion was verified by measuring spleen NK-cell activity. The resulting colonic inflammation in all these types of deficient mice was qualitatively comparable, as shown by clinical and histological appearance. These results indicate that the presence of functional T, B and NK cells is not crucial for the induction of dextran sulfate colitis in mice.

Induction of and adaptation to olsalazine induced intestinal volume load.

Olsalazine is a new drug for the treatment of ulcerative and Crohn's colitis. The toxicological, pharmacological and pharmacokinetic profiles of olsalazine are excellent; the only side-effect noted from clinical trials with olsalazine is an increased incidence of loose stools and occasional diarrhoea. At high olsalazine concentrations, a direct effect on the net water absorption of the intestine is apparent. This effect is not due to a decrease in absorption, but to an induction of a rapidly reversible, Cl- dependent water secretion. In rats experimentally subjected to olsalazine induced diarrhoea (150 mg/kg), a total adaptation occurs within 3-4 days. This adaptation is not due to tachyphylaxis, but to an increased absorption capacity in the colon and caecum. Similar adaptation has been noted in other species including man.

The incorporation of selenium and alterations of macro- and trace element levels in individual blood cells following supplementation with sodium selenite and vitamin E : A nuclear microprobe application.

Significant alterations in the selenium content of erythrocytes, thrombocytes, and neutrophil granulocytes were observed following a daily supplementation of 200 µg Se + 100 mg vitamin E during a period of 2 months. The neutrophil granulocytes incorporated more selenium than the thrombocytes. The iron content of the thrombocytes decreased on selenium supplementation, while the opposite was noted for the neutrophil granulocytes. The glutathione peroxidase activity was not significantly changed during the period of observation.