title: Docosahexaenoic acid suppresses nitric oxide production and inducible nitric oxide synthase expression in interferon-gamma plus lipopolysaccharide-stimulated murine macrophages by inhibiting the oxidative stress.
abstract: N-3 polyunsaturated fatty acids (PUFAs) are known to have anti-inflammatory effects. Excess production of nitric oxide (NO) is associated with inflammation. Therefore, we examined the effects of PUFAs on NO production and inducible NO synthase (iNOS) expression by stimulated murine macrophages. One typical n-3 PUFA docosahexaenoic acid (DHA) strongly inhibited NO production and iNOS expression in RAW264 macrophages and mouse peritoneal macrophages in a dose-dependent manner. This inhibition was accompanied by inhibiting the oxidative stress-sensitive transcription factor nuclear factor (NF)-kappaB activation. In stimulated macrophages, intracellular peroxides level was enhanced, but pretreatment of DHA dose-dependently inhibited this enhancement. These results suggest that DHA has an antioxidative effect based on the inhibition of the accumulation of intracellular peroxides, and this inhibition caused the suppression of the activation of NF-kappaB, resulting in the inhibition of NO production and iNOS expression. On the other hand, DHA treatment enhanced the level of intracellular glutathione (GSH), and this enhancement is thought to mediate the activity of DHA because lowering the GSH level by inhibiting GSH biosynthesis reversed the DHA-induced suppression of NO production, NF-kappaB activation, and the accumulation of intracellular peroxides. Our results demonstrate that DHA inhibits NO production in macrophages and this inhibition is, in part, mediated by upregulation of GSH.
authors.affiliation: Department of Human Nutrition and Food Management, Toita Women's College, Tokyo, Japan.
authors.forename: Wataru
authors.initials: W
authors.lastname: Komatsu
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishihara
authors.forename: Masakazu
authors.initials: M
authors.lastname: Murata
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Saito
authors.forename: Kazuki
authors.initials: K
authors.lastname: Shinohara
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002460:Cell Line; D004281:Docosahexaenoic Acids / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005227:Fatty Acids / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D007249:Inflammation; D007371:Interferon-gamma / Q000378:metabolism / Q000494:pharmacology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D052247:Nitric Oxide Synthase Type II; D018384:Oxidative Stress; D010545:Peroxides / Q000378:metabolism; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D005227:Fatty Acids; D008070:Lipopolysaccharides; D016328:NF-kappa B; D010545:Peroxides; D004281:Docosahexaenoic Acids; D009569:Nitric Oxide; D012313:RNA; D007371:Interferon-gamma; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496317:Nos2 protein, mouse; D005978:Glutathione