Eicosapentaenoic acid modulates arachidonic acid metabolism in rat alveolar macrophages activated by silica

Abstract

Eicosapentaenoic acid (EPA) was used to modulate the activation of alveolar macrophages, to examine its potential anti-inflammatory effect in addition to its anti-arteriosclerotic or anti-thrombotic effects. Wistar strain rat alveolar macrophages (2 × 10 6cell) obtained by bronchoalveolar lavage were preincubated with EPA (0–20 μM), and further incubated with 1 mg of silica for 90 min. Leukotriene (LT) B 4and LTB 5of the supernatant were analyzed by reverse phase HPLC. EPA inhibited the production of LTB 4dose-dependently. The production of LTB 5, a metabolite from EPA, was increased at low concentrations of EPA (0–10 μM) and decreased at high concentrations (⪢ 10 μM). These results suggest that EPA is competitive with arachidonic acid (AA) at low concentrations, and that EPA may inhibit AA metabolism via inhibition of 5-lipoxygenase or phospholipase A 2at high concentrations.