EFFECT OF ANTIINFLAMMATORY COMPOUNDS ON EDEMA FORMATION AND MYELOPEROXIDASE ACTIVITY IN THE ARACHIDONIC ACID-INDUCED EAR MODEL IN THE MOUSE

The arachidonic acid (AA)-induced ear edema model in the mouse has bee n demonstrated as an effective in vivo experimental tool to screen com pounds showing anti-inflammatory activity. Since neutrophil influx is a component of the inflammatory reaction, we have modified this assay by quantitating myeloperoxidase (MPO) levels which reflect neutrophil accumulation in the edematous biopsies of the mouse ear. Our work has shown that orally administered 5-lipoxygenase inhibitors, dual inhibit ors (CO/LO), and steroids dose-dependently inhibit both edema formatio n and MPO activity, whereas oral activity is not seen with NSAID's. Th ere is a good correlation between the inhibition of edema formation an d of MPO activity by these compounds. Thus, measurement of MPO, in add ition to the AA-induced edema in the mouse ear, can provide another pa rameter to profile potential anti-inflammatory compounds.