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

Introduction. Docosahexaenoic acid (DHA) has been shown to be immunosuppressive in the fetus, and fish oil diets are thought to be beneficial in autoimmune disease and transplantation. This effect may be mediated through nitric oxide (NO). Here, we investigate the effect of DHA on murine macrophages. Methods. Peritoneal macrophages were subjected to stimulation with various concentrations of interferon γ-(IFN-γ) and tumor necrosis factor α (TNF-α). NO production was assessed by measuring nitrite (Greiss reaction). Results. At all doses of IFN-γ and TNF-α, DHA was found to be inhibitory to NO production. Conclusions. DHA inhibits macrophage- stimulated NO production in response to IFN-γ and TNF-α As NO is thought to be important in several disease processes, DHA may be a useful agent in the treatment of conditions such as autoimmune disease.