Prostaglandin and Leukotriene Synthesis in Mouse Ears Inflamed by Arachidonic Acid

Topical application of arachidonic acid on mouse ears induces the synthesis of prostaglandin E2 and leukotrienes C4 and D4. The increased tissue levels of these products are quantitated by radioimmunoassay. The identity of the leukotrienes was confirmed by immunoreactivity of reverse-phase high-performance liquid chromatography fractions corresponding to authentic standards. Synthesis of the arachidonic acid metabolites precedes or is coincident with increased vascular permeability resulting in an edematous response, as measured by accumulation of [125I]albumin in the ear after i.v. injection or by tissue wet weight. When applied topically, anti-inflammatory drugs such as BW755C (3-amino-1-(m-[trifluoromethyl]phenyl)2-pyrazoline, indomethacin, and nordihydroguaiaretic acid inhibit edema and modulate the appearance of the arachidonic acid products. The data suggest the coinvolvement of prostaglandin E2 and leukotrienes C4 and D4 as mediators of inflammation in this in vivo model