Enhanced nitric oxide production associated with airway hyporesponsiveness in the absence of IL-10

Bill T. Ameredes, Jigme M. Sethi, He Liang Liu, Augustine M.K. Choi, William J. Calhoun

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Interleukin (IL)-10 is an anti-inflammatory cytokine implicated in the regulation of airway inflammation in asthma. Among other activities, IL-10 suppresses production of nitric oxide (NO); consequently, its absence may permit increased NO production, which can affect airway smooth muscle contractility. Therefore, we investigated airway reactivity (AR) in response to methacholine (MCh) in IL-10 knockout (-/-) mice compared with wild-type C57BL/6 (C57) mice, in which airway NO production was measured as exhaled NO (E NO), and NO production was altered with administration of either NO synthase (NOS)-specific inhibitors or recombinant murine (rm)IL-10. AR, measured as enhanced pause in vivo, and tracheal ring tension in vitro were lower in IL-10-/- mice by 25-50%, which was associated with elevated E NO levels (13 vs. 7 ppb). Administration of NOS inhibitors N G-nitro-L-arginine methyl ester (8 mg/kg ip) or L-N G-(1-iminoethyl)-lysine (3 mg/kg ip) to IL-10-/- mice decreased ENO by an average of 50%, which was associated with increased AR, to levels similar to C57 mice. ENO in IL-10 -/- mice decreased in a dose-dependent fashion in response to administered rmIL-10, to levels similar to C57 mice (7 ppb), which was associated with a 30% increment in AR. Thus increased NO production in the absence of IL-10, decreased AR, which was reversed with inhibition of NO, either by inhibition of NOS, or with reconstitution of IL-10. These findings suggest that airway NO production can modulate airway smooth muscle contractility, resulting in airway hyporesponsiveness when IL-10 is absent.

Original languageEnglish (US)
Pages (from-to)L868-L873
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number5 32-5
StatePublished - May 2005
Externally publishedYes


  • Airway smooth muscle
  • Exhaled nitric oxide
  • Interleukin-10 knockout mice
  • Methacholine

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine
  • Cell Biology
  • Physiology


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