ABSTRACT
The intestinal mucosa from a variety of different species including human, rat, pig, dog and cat contains relatively high concentrations of hemoprotein peroxidase activity. Histochemical analysis reveals that virtually all of this peroxidase is associated with resident granulocytes whereas macrophages, basophils and mast cells contain only trace amount of peroxidase. The apparent association between neutrophil infiltration and mucosal injury has prompted us to propose that neutrophils may play an active role in mediating some of the mucosal injury observed in ulcerative colitis. Inflammatory neutrophils possess an arsenal of potentially cytotoxic weapons that can be released into the mucosal interstitium. Interaction of certain ligands with specific receptors on the plasma membrane of neutrophils and eosinophils results in the activation of the latent, plasma membrane associated NADPH oxidase. Enzyme activation results in enhanced consumption of molecular oxygen and production of large quantities of superoxide and hydrogen peroxide.
