DIETARY N-3 FATTY-ACIDS ALTER MURINE PERITONEAL MACROPHAGE CYTOTOXICITY

Male CD-1 mice were fed diets containing 10 wt% fat composed of a cons tant amount of n-6 polyunsaturated fatty acids (PUFA; safflower oil, 1 .5 wt%) and increasing levels of n-3 PUFA (up to 1.5 wt%); the remaini ng fat was a 50:50 mixture of tripalmitin and triolein. Four days prio r to sacrifice, the animals were injected intraperitoneally with steri le thioglycollate. Peritoneal macrophages were analyzed for phospholip id fatty acids, prostaglandin E2 (PGE2) synthesis and cytotoxicity tow ards L929 target cells. Increasing dietary n-3 PUFA increased macropha ge phospholipid n-3 PUFA from 4.4 to 11.0 mol% with a concomitant decl ine in n-6 PUFA from 15.5 to 10.9 mol%, and PGE2 synthesis declined fr om 2.6 to 1.5 pmol/million cells in thioglycollate-elicited macrophage s. Macrophage cytotoxicity toward target L929 cells declined by approx imately 50% with increasing n-3 PUFA concentration.