Dietary lipids modify the cytokine response to bacterial lipopolysaccharide in mice

To investigate the effect of dietary lipids with different fatty acid compo sitions upon the in vivo cytokine response to bacterial lipopolysaccharide (LPS), mice were fed for 5 weeks on a low-fat diet or on one of four high-f at diets that contained 20%, by weight, of coconut oil (CO), olive oil (OO) , safflower oil (SO) or fish oil (FO). The mice were injected intraperitone ally with a non lethal dose of Escherichia coli LPS (100 mu g/20 g body wei ght) and killed 90 or 180 min later. Plasma tumour necrosis factor-alpha (T NF-alpha), interleukin (IL)-1 alpha, IL-6 and IL-10 concentrations were mea sured by enzyme-linked immunosorbent assay (ELISA). Plasma TNF-alpha and IL -10 concentrations were higher 90 min postinjection than after 180 min, whe reas plasma IL-1 beta and IL-6 concentrations were higher 180 min postinjec tion than after 90 min. Peak plasma TNF-alpha, IL-1 beta and IL-6 concentra tions were lower in the CO- and FO-fed mice than in those fed the SO diet. Peak plasma IL-10 concentrations were higher in GO-fed mice than in those f ed some of the other diets. These observations suggest that, relative to th e n-6 polyunsaturated fatty acid-rich SO diet, CO and FO diminish productio n of proinflammatory cytokines in vivo. This indicates that these fatty aci ds might be useful therapies in acute and chronic inflammatory diseases. Th e enhanced production of IL-10 following CO feeding appears to be an additi onal antiinflammatory effect of this oil, which could give added benefit in various clinical conditions.