Effect of apocynin on the induction of ulcerative lesions in rat skin injected with tubercle bacteria.

Apocynin is an effective and selective inhibitor of the neutrophil oxidative burst in vitro. Other neutrophil functions, tested in vitro, such as chemotaxis, exocytosis, phagocytosis and intracellular killing of bacteria are unaffected by apocynin. These properties make apocynin a potential anti-inflammatory agent in vivo. This was tested in WAG/Rij rats, injected intracutaneously with tubercle bacteria in oil (complete Freund's adjuvant). We show here that continuous administration of apocynin via the drinking water prevents the formation of ulcerative lesions in the inflamed skin. No effects on humoral and cellular immunity were observed after treatment with apocynin (between 1 and 100 micrograms/ml drinking water) measuring serum antibodies and delayed-type hypersensitivity, respectively.