Neutrophil-infiltrated paw edema induced by mannose-binding Dioclea violacea lectin.

BACKGROUND The potential edematogenic effect and the pharmacological characterization of a glucose-mannose-binding lectin from Dioclea violacea (DvL) were investigated. METHODS Paw edema was induced with DvL in control animals, and in animals pretreated with glucocorticoid or with blockers of histamine, nitric oxide synthase, cyclooxygenase, platelet activating factor (PAF), bradykinin and lipoxygenase. RESULTS DvL-induced paw edema paralleled with an increase in vascular permeability and myeloperoxidase (MPO) activity. DvL-induced edema could be prevented by pre-treatment with the lectin-binding sugar α-D-methyl mannoside. Dexamethasone, meclizine and Nω-nitro-L-arginine methyl ester hydrochloride (L-NAME) inhibited this effect. CONCLUSIONS DvL induces edema, increase in vascular permeability and neutrophil infiltration. The edematogenic activity involves the lectin mannose-binding sites and is associated with histamine, cytokines and nitric oxide, since it could be treated with meclizine, dexamethasone and L-NAME.