Effects of dietary n-3 or n-6 fatty acids on interleukin-1β-induced anxiety, stress, and inflammatory responses in rats

The present study demonstrated that an omega (n)-3 fatty acid, ethyl-eicosapentaenoic acid (ethyl-EFA), supplemented diet significantly attenuated the stress/anxiety behavior of rats in the "open field" and elevated plus maze, which was induced by subchronic intracerebroventricular administration. of proinflammatory cytokine interleukin (IL)-1beta. Ethyl-EPA also reduced the rise in serum corticosterone induced by IL-1. The n-6 fatty acid ediyl-gamma-linolenic acid (ethyl-GLA) had little effect on the IL-1-induced changes in behavior and the corticosterone concentration. Following IL-1beta administration, ethyl-EFA reduced the elevated prostaglandin (PG) E2 secretion and increased the secretion of antiinflammatory cytokine IL-10 from whole blood cells. Ethyl-GLA showed a similar antiinflammatory effect to ethyl-EPA. By contrast, n-6 fatty acid arachidonic acid (AA) had no effect on the behavior, immune, and endocrine changes induced by IL-1. AA alone enhanced the basal inflammatory response, raised serum corticosterone concentrations, and induced anxiety behavior in the elevated plus maze. The reduced growth rates of rats following the administration-of IL-1 was attenuated by ethyl-EFA, and to a greater extent by ethyl-EPA plus ethyl-GLA, but not by AA alone or in combination with ethyl-EPA. jlr Thus, ethyl-EPA would appear to antagonise the endocrine, immune, and behavioral effects of subchronic UL-1 administration. Ethyl-GLA only antagonised IL-1-induced inflammatory changes, whereas AA caused an increase in the secretion of corticosterone and PGE2, and induced anxiety-like behavior without enhancing the effects of IL-1.-Song, C., X. Li, B. E. Leonard, and D. R Horrobin. Effects-of dietary n-3 or n-6 fatty acids on interleukin-1beta-induced anxiety, stress, and inflammatory responses in rats. J. Lipid-Res. 2003. 44:1984-1991.