In vivo lipid-derived free radical formation by NADPH oxidase in acute lung injury induced by lipopolysaccharide: a model for ARDS.
Intratracheal instillation of lipopolysaccharide (LPS) activates alveolar macrophages and infiltration of neutrophils, causing lung injury/acute respiratory distress syndrome. Free radicals are a special focus as the final causative molecules in the pathogenesis of lung injury caused by LPS. Although in vitro investigation has demonstrated radical generation after exposure of cells to LPS, in vivo evidence is lacking. Using electron spin resonance (ESR) and the spin trap alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (POBN), we investigated in vivo free radical production by rats treated with intratracheal instillation of LPS. ESR spectroscopy of lipid extract from lungs exposed to LPS for 6 h gave a spectrum consistent with that of a POBN/carbon-centered radical adduct (aN=14.94+/-0.07 G and abetaH=2.42+/-0.06 G) tentatively assigned as a product of lipid peroxidation. To further investigate the mechanism of LPS-initiated free radical generation, rats were pretreated with the phagocytic toxicant GdCl3, which significantly decreased the production of radical adducts with a corresponding decrease in neutrophil infiltration. NADPH oxidase knockout mice completely blocked phagocyte-mediated, ESR-detectable radical production in this model of acute lung injury. Rats treated intratracheally with LPS generate lipid-derived free radicals via activation of NADPH oxidase.
Sato
Keizo
K
Free Radical Metabolite Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA. sato@niehs.nih.gov
Kadiiska
Maria B
MB
Ghio
Andrew J
AJ
Corbett
Jean
J
Fann
Yang C
YC
Holland
Steven M
SM
Thurman
Ronald G
RG
Mason
Ronald P
RP
D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry / Q000166:cytology; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy; D005260:Female; D005609:Free Radicals / Q000378:metabolism*; D005682:Gadolinium / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D050356:Lipid Metabolism; D008070:Lipopolysaccharides / Q000008:administration & dosage* / Q000633:toxicity; D008168:Lung / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008815:Mice, Inbred Strains; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D009589:Nitrogen Oxides / Q000008:administration & dosage / Q000633:toxicity; D010586:Phagocytes / Q000166:cytology / Q000187:drug effects; D011506:Proteins / Q000187:drug effects / Q000378:metabolism; D011725:Pyridines; D051381:Rats; D017207:Rats, Sprague-Dawley; D012127:Respiratory Distress Syndrome, Newborn / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology
D005609:Free Radicals; D008070:Lipopolysaccharides; D009589:Nitrogen Oxides; D011506:Proteins; D011725:Pyridines; C043438:alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone; D005682:Gadolinium; D019255:NADPH Oxidases; C038958:gadolinium chloride