title: Redox-sensitive regulation of macrophage-inducible nitric oxide synthase expression in vitro does not correlate with the failure of apocynin to prevent lung inflammation induced by endotoxin.
abstract: Reactive oxygen and nitrogen species are among the crucial mediators in the development of the pathological inflammatory process in the lungs and contribute to the damage of lung epithelium. The aim of the present study was to evaluate the potential of selected antioxidants or inhibitors of NADPH oxidase (glutathione, N-acetyl cysteine, trolox, apocynin, and diphenyleneiodonium chloride) to modulate nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression by mouse macrophages induced by lipopolysaccharide (LPS) in vitro and to evaluate the potential of apocynin to modulate the course of LPS-induced lung inflammation in vivo. All the tested drugs revealed inhibitory effects on LPS-induced NO production and iNOS expression in RAW 264.7 macrophages. Further, apocynin significantly inhibited activation of nuclear factor kappa B induced by LPS. Ex vivo, diphenyleneiodonium chloride and apocynin significantly reduced ROS production by inflammatory cells isolated from bronchoalveolar lavage fluid. In contrast, in vivo intranasal application of apocynin did not exert any significant effect on the course of lung inflammation in mice induced by LPS that was evaluated based on the accumulation of cells, interleukine-6, interleukine-12, RANTES, tumor necrosis factor-alpha, and protein concentration in bronchoalveolar lavage fluid and expression of iNOS in lung tissue. Only effected were the levels of nitrites 36 h after induction of lung inflammation that were reduced in the apocynin-treated group. In conclusion, our data suggest that the inhibitors of NADPH oxidase possess inhibitory potential against LPS-induced NO production by mouse macrophages; however, apocynin failed to reduce LPS-induced lung inflammation in mice.
authors.affiliation: Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, CZ-612 65 Brno, Czech Republic.
authors.forename: Daniela
authors.initials: D
authors.lastname: Viačková
authors.forename: Michaela
authors.initials: M
authors.lastname: Pekarová
authors.forename: Tomáš
authors.initials: T
authors.lastname: Crhák
authors.forename: Martina
authors.initials: M
authors.lastname: Búcsaiová
authors.forename: Ján
authors.initials: J
authors.lastname: Matiašovic
authors.forename: Antonín
authors.initials: A
authors.lastname: Lojek
authors.forename: Lukáš
authors.initials: L
authors.lastname: Kubala
mesh_terms: D000098:Acetophenones / Q000494:pharmacology*; D000276:Adjuvants, Immunologic / Q000494:pharmacology; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002460:Cell Line; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D008070:Lipopolysaccharides / Q000378:metabolism / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D011014:Pneumonia / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism / Q000517:prevention & control; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000098:Acetophenones; D000276:Adjuvants, Immunologic; D000975:Antioxidants; D004791:Enzyme Inhibitors; D008070:Lipopolysaccharides; D016328:NF-kappa B; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; C056165:acetovanillone; D052247:Nitric Oxide Synthase Type II; D019255:NADPH Oxidases