Effects of linoleic acid-rich diet on plasma profiles of eicosanoids and development of colitis in Il-10-/- mice.

Dietary intake of linoleic acid (LA, 18:2ω-6) has risen dramatically in recent decades. Previous studies have suggested high intake of LA could increase tissue concentrations of pro-inflammatory and pro-tumorigenic ω-6-series eicosanoid metabolites, increasing risks of inflammation and associated diseases. However, the effects of LA-rich diet on in vivo profiles of eicosanoids and development of inflammatory diseases are under-studied. Here we treated spontaneous colitis-prone (Il-10-/-) mice with a control diet (~3 Cal% LA) or a LA-rich diet (~9 Cal% LA) for 18 weeks, and analyzed the effects of the LA-rich diet on profiles of eicosanoids and development of colitis. We found that treatment with the LA-rich diet increased tissue level of LA: the liver levels of LA were 5.8 ± 0.6% in control diet-treated mice versus 11.7 ± 0.7% in LA-rich diet-treated mice (P < 0.01). The plasma concentrations of a series of LA-derived metabolites, including 9-hydroxyoctadecadienoic acid (HODE), 9,10-dihydroxyoctadecenoic acid (DiHOME), 12,13-DiHOME, and 13-HODE were significantly increased by treatment with the LA-rich diet (P < 0.05). However, LA-rich diet had little effect on the severity of colitis in the treated Il-10-/- mice. These results suggest a limited role of increased consumption of dietary LA on promoting colitis in Il-10-/- model.