CHEMILUMINESCENCE ASSAY OF MUCOSAL REACTIVE OXYGEN METABOLITES IN INFLAMMATORY BOWEL-DISEASE

Previous studies suggesting increased reactive oxygen metabolite (ROM) production in inflammatory bowel disease have been restricted to peripheral blood and isolated intestinal phagocytes. In the current study, chemiluminescence and the effect of various scavengers, enzymes, and enzyme inhibitors were used to show that ROMs account for the increased production of oxidants by colorectal mucosal biopsy specimens in inflammatory bowel disease. Luminol-amplified chemiluminescence was increased in active ulcerative colitis [macroscopic grade 1: 25 photons · mg-1 · min · 10-3 (median), 8-47 (95% confidence intervals), n = 40; grade 2: 89, 65-156, n = 30; grade 3: 247, 133-562, n = 13] and Crohn's disease [mild: 9, 3-84, n = 6; severe: 105, 25-789 (range), n = 5] compared with normal-looking mucosa (ulcerative colitis: 0.8, 0.4-1.4, n = 22, P < 0.01; Crohn's disease: 0.8, 0.1-2, n = 6, P < 0.05) and controls (0.6, 0.04-1.4, n = 52, P < 0.01). In ulcerative colitis, luminol chemiluminescence correlated with microscopic inflammation (Spearman's ρ{variant} = 0.74, P = 0.0001) and was decreased by sodium azide (-89%, P < 0.05), taurine (-31%, P < 0.05), catalase (-23%, P < 0.05), and dimethyl sulfoxide (-29%, P < 0.05). Superoxide dismutase and oxypurinol decreased lucigenin chemiluminescence in ulcerative colitis by -63% (P < 0.05) and -27% (P < 0.05), respectively. Luminol chemiluminescence correlated with lucigenin chemiluminescence (Spearman's ρ{variant} = 0.62, P = 0.0001) and myeloperoxidase activity (Spearman's ρ{variant} = 0.72, P = 0.003). These results suggest that neutrophil-derived oxidants (superoxide, hydrogen peroxide, hydroxyl radical, and hypochlorite) are generated in colorectal mucosa in active inflammatory bowel disease and support the hypothesis that production of such metabolites by neutrophils is of major pathogenetic importance. © 1992.