Abstract
We studied the effects of ozone exposure and dexamethasone on inducible nitric synthase (iNOS) gene expression in Brown Norway rats in vivo. Using a murine iNOS cDNA probe, we detected a 4.4 kb iNOS mRNA by Northern analysis in rat lung. The iNOS signal was weak in control lungs, but increased in lungs exposed to ozone (3 ppm, 6 h). Ozone-induced iNOS mRNA expression was time-dependent, with maximal expression at 2 h, declining by 8 h and increasing again at 24 h postexposure. Dexamethasone significantly reduced the iNOS mRNA expression in the lungs of both controls and ozone-exposed rats. These results demonstrate that ozone inhalation induces iNOS expression in vivo, thus providing evidence at the molecular level for the possible involvement of nitric oxide generation in ozone-induced pulmonary inflammation or lung damage.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Administration, Inhalation
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Animals
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Anti-Inflammatory Agents / pharmacology*
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Base Sequence
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Blotting, Northern
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Bronchoalveolar Lavage Fluid / cytology
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Cell Count
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DNA Primers / chemistry
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DNA Probes
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Dexamethasone / pharmacology*
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Female
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Gene Expression Regulation, Enzymologic / drug effects
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Injections, Intraperitoneal
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Lung / drug effects
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Lung / enzymology*
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Molecular Sequence Data
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Nitric Oxide Synthase / biosynthesis*
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Nitric Oxide Synthase / genetics
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Oxidants, Photochemical / administration & dosage
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Oxidants, Photochemical / toxicity*
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Ozone / administration & dosage
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Ozone / toxicity*
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RNA, Messenger / biosynthesis
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Rats
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Rats, Inbred BN
Substances
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Anti-Inflammatory Agents
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DNA Primers
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DNA Probes
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Oxidants, Photochemical
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RNA, Messenger
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Ozone
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Dexamethasone
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Nitric Oxide Synthase