Inducible nitric oxide synthase in the lung and exhaled nitric oxide after hyperoxia

Giovanni Cucchiaro, Arthur H. Tatum, Michael C. Brown, Enrico M. Camporesi, John W. Daucher, Tawfic S. Hakim

Research output: Contribution to journalArticle

Abstract

The effect of hyperoxia on nitric oxide (NO) production in intact animals is unknown. We described the effects of hyperoxia on inducible nitric oxide synthase (iNOS) expression and NO production in the lungs of rats exposed to high concentrations of oxygen. Animals were placed in sealed Plexiglas chambers and were exposed to either 85% oxygen (hyperoxic group) or 21% oxygen (negative control group). Animals were anesthetized after 24 and 72 h of exposure and were ventilated via a tracheotomy. We measured NO production in exhaled air (E(NO)) by chemiluminescence. The lungs were then harvested and processed for detection of iNOS by immunohistochemistry and Western blotting analysis. The same experiments were repeated in animals exposed to hyperoxia for 72 h after they were infused with L-arginine. We used rats that were injected intraperitoneally with Escherichia coli lipopolysaccharide to induce septic shock as a positive control group. Hyperoxia and septic shock induced expression of iNOS in the lung. However, E(NO) was elevated only in septic shock rats but was normal in the hyperoxic group. Exogenous infusion of L-arginine after hyperoxia did not increase E(NO). To exclude the possibility that in the hyperoxic group NO was scavenged by oxygen radicals to form peroxynitrite, lungs were studied by immunohistochemistry for the detection of nitrotyrosine. Nitrotyrosine was found in septic shock animals but not in the hyperoxic group, further suggesting that NO is not synthesized in rats exposed to hyperoxia. We conclude that hyperoxia induces iNOS expression in the lung without an increase in NO concentration in the exhaled air.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Volume277
Issue number3 21-3
StatePublished - Sep 1 1999
Externally publishedYes

Fingerprint

Hyperoxia
Nitric Oxide Synthase Type II
Nitric Oxide
Lung
Septic Shock
Oxygen
Arginine
Immunohistochemistry
Air
Tracheotomy
Control Groups
Peroxynitrous Acid
Polymethyl Methacrylate
Luminescence
Lipopolysaccharides
Reactive Oxygen Species
Western Blotting
Escherichia coli

Keywords

  • Hyperoxia
  • Septic shock

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology

Cite this

Inducible nitric oxide synthase in the lung and exhaled nitric oxide after hyperoxia. / Cucchiaro, Giovanni; Tatum, Arthur H.; Brown, Michael C.; Camporesi, Enrico M.; Daucher, John W.; Hakim, Tawfic S.

In: American Journal of Physiology - Lung Cellular and Molecular Physiology, Vol. 277, No. 3 21-3, 01.09.1999.

Research output: Contribution to journalArticle

Cucchiaro, Giovanni ; Tatum, Arthur H. ; Brown, Michael C. ; Camporesi, Enrico M. ; Daucher, John W. ; Hakim, Tawfic S. / Inducible nitric oxide synthase in the lung and exhaled nitric oxide after hyperoxia. In: American Journal of Physiology - Lung Cellular and Molecular Physiology. 1999 ; Vol. 277, No. 3 21-3.
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