iNOS depletion completely diminishes reactive nitrogen-species formation after an allergic response

A. Koarai, M. Ichinose, H. Sugiura, M. Tomaki, M. Watanabe, S. Yamagata, Y. Komaki, K. Shirato, T. Hattori

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)

Abstract

Nitric oxide (NO) shows proinflammatory actions mainly via reactive nitrogen species (RNS) formation through superoxide- and peroxidase-dependent mechanisms. The purpose of this study was to examine the role of inducible NO synthase (iNOS) in RNS production, airway hyperresponsiveness, and inflammation after allergen challenge. Ovalbumin (OVA)-sensitised, iNOS-deficient and wild-type mice were used. RNS production was assessed by nitrotyrosine (NT) immunoreactivity in the airways. Airway inflammation and responsiveness were evaluated by eosinophil accumulation and methacholine (i.v.) challenge, respectively. In wild-type mice, OVA-inhalation challenge increased iNOS immunoreactivity in airway epithelial cells as well as iNOS protein measured by Western blotting. The total amounts of nitrite and nitrate in bronchoalveolar lavage (BAL) fluid were increased, and NT immunoreactivity was also observed abundantly in airway inflammatory cells. In iNOS-deficient mice, both iNOS expression and NT formation were completely abolished, and the total amounts of nitrite and nitrate in BAL fluid were significantly decreased. In contrast, OVA-induced airway eosinophil recruitment and hyperresponsiveness were observed almost equally in wild-type and iNOS-deficient mice. These data suggest that reactive nitrogen species production after allergic reaction occurs totally via inducible nitric oxide synthase-dependent pathways. Allergen-mediated airway eosinophil recruitment and hyperresponsiveness appear to be independent of reactive nitrogen species production.

Original languageEnglish
Pages (from-to)609-616
Number of pages8
JournalEuropean Respiratory Journal
Volume20
Issue number3
DOIs
Publication statusPublished - 2002 Sep

Keywords

  • Airway inflammation
  • Airway responsiveness
  • Asthma
  • Nitric oxide
  • Nitrotyrosine

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

Fingerprint Dive into the research topics of 'iNOS depletion completely diminishes reactive nitrogen-species formation after an allergic response'. Together they form a unique fingerprint.

Cite this