Effects of tumour necrosis factor-alpha synthesis inhibitors on rat trinitrobenzene sulphonic acid-induced chronic colitis.

The fact that tumour necrosis factor-alpha (TNF-alpha) is clearly involved in the pathogenesis of intestinal bowel disease, especially Crohn's disease, suggests that TNF-alpha synthesis inhibitors could be beneficial for treatment. The present study assessed the effect of chronic oral gavage of two in vitro TNF-alpha synthesis inhibitors, JM 34 maleate or [N-(4,6-dimethylpyridin-2-yl)-furane-2-carboxamide)] maleate and XC 21 or (N-betapicolyl-tetrafluorophtalimide), on colonic inflammation in trinitrobenzene sulphonic acid-induced colitis in rats. Rats received JM 34 maleate (100 mg/kg) and XC 21 (50 mg/kg) 1 h before colitis induction and then daily for 8 days by oral gavage. The colon was removed on day 8 and processed for clinical score, myeloperoxidase activity, and soluble TNF-alpha release. Treatment with XC 21, as well as dexamethasone and sulphasalazine, reduced colonic damage and decreased (except with dexamethasone) the incidence of diarrhoea. JM 34 maleate failed to improve the clinical signs of chronic colitis. After trinitrobenzene sulphonic acid-induced colitis, myeloperoxidase activity and TNF-alpha colonic mucosal production were substantially increased compared to the control (saline instillation). Both of these inflammatory indicators were then significantly decreased (P< or =0.05) after the four chronic treatments (JM 34 maleate, XC 21, sulphasalazine, and dexamethasone). XC 21 appeared to be as efficient as sulphasalazine in improving colonic inflammation.