Docosahexaenoic acid, a component of fish oil, inhibits nitric oxide production in vitro

Introduction. Docosahexaenoic acid (DHA) has been shown to be immunosuppres sive in the fetus, and fish oil diets are thought to be beneficial in autoi mmune disease and transplantation. This effect may be mediated through nitr ic oxide (NO), Here, we investigate the effect of DHA on murine macrophages , Methods. Peritoneal macrophages were subjected to stimulation with various concentrations of interferon gamma-(IFN-gamma) and tumor necrosis factor al pha (TNF-alpha). NO production was assessed by measuring nitrite (Greiss re action), Results. At all doses of IFN-gamma and TNF-alpha, DHA was found to be inhib itory to NO production, Conclusions. DHA inhibits macrophage-stimulated NO production in response t o IFN-gamma and TNF-alpha. As NO is thought to be important in several dise ase processes, DHA may be a useful agent in the treatment of conditions suc h as autoimmune disease. (C) 1999 Academic Press.