RESUMO
The inflammatory reaction induced by the intradermal injection of arachidonic acid into the rabbit dermis has been investigated. Plasma extravasation was measured by the leakage of 125I-albumin into the tissues and polymorphonuclear leukocyte (PMNL) accumulation was assessed histologically. Arachidonic, 5,8,11,14,17-eicosapentaenoic and 8,11,14-eicosatrienoic acids, but not oleic, linoleic or linolenic acids, caused a concentration-related plasma extravasation following their intra-dermal injection. The plasma extravasation induced by arachidonic acid was dependent on PMNLs. PMNL infiltration and plasma extravasation into arachidonic acid-injected skin sites was inhibited by the mixed cyclo-oxygenase-lipoxygenase inhibitor, BW755C. Arachidonic acid-induced plasma extravasation was inhibited by cyclo-oxygenase and 5-lipoxygenase inhibitors but not by the Paf antagonist, kadsurenone. The inflammation induced by arachidonic acid in the rabbit dermis may be a useful model for evaluating 5-lipoxygenase inhibitors which could be potentially useful anti-inflammatory agents for the treatment of psoriasis and other inflammatory diseases.