Lack of beneficial effect of COX-2 inhibitors in an experimental model of colitis.

Expression of the COX-2 enzyme has been reported in animal models of inflammatory bowel disease (IBD) as well as in patients affected by ulcerative colitis and Crohn 's disease. Recently, selective inhibitors of COX-2 have become available. In this study we have evaluated three highly selective COX-2 inhibitors, NS-398, SC-58125 and PD-138387, on the trinitro-benzene sulfonic acid (TNBS) model of colitis in rats. Daily oral administration of the three compounds evaluated up to a dose of 100 mg/kg failed to significantly modify any of the parameters evaluated. Our data show that despite their potent extraintestinal antiinflammatory activity, COX-2 inhibitors do not seem to have any beneficial effect in TNBS colitis and raise the question whether this therapeutic approach would he beneficial in patients with IBD.