Increasing the dietary (n-3) to (n-6) polyunsaturated fatty acid ratio increases tumor necrosis factor production by murine resident peritoneal macrophages without an effect on elicited peritoneal macrophages.

Tumor necrosis factor (TNF), prostaglandin (PG) E2 and 6-keto-PGF1 alpha production by murine peritoneal macrophages was monitored following in vitro stimulation with lipopolysaccharide. Macrophages were obtained from mice fed diets containing increasing ratios of (n-3) to (n-6) fatty acids by addition of (n-3) polyunsaturated fatty acids (PUFA) to the (n-6) fatty acids in the diet, or by substituting (n-3) PUFA for the (n-6) fatty acids in the diet. Increasing the dietary (n-3) to (n-6) fatty acid ratio from 0 to 1 increased both cell-associated and secreted TNF production by resident peritoneal macrophages but did not affect TNF production by macrophages elicited with Complete Freund's Adjuvant (CFA). With increasing dietary (n-3): (n-6) ratio there was a decrease in the prostaglandin production by resident peritoneal macrophages, which may partly explain the increased TNF production. The CFA-elicited macrophages produced less prostaglandin than the resident macrophages, and the lower prostaglandin production may partly explain the lack of effect of dietary (n-3) PUFA on TNF production by CFA-elicited macrophages. Increasing the TNF production by resident macrophages with dietary (n-3) PUFA may be beneficial in enhancing antitumor actions and antipathogenicity; by not increasing the high TNF production of inflammatory macrophages, (n-3) PUFA may protect against undesirable systemic inflammatory effects of overproduction.