Role of reactive nitrogen species generated via inducible nitric oxide synthase in vesicant-induced lung injury, inflammation and altered lung functioning

Toxicol Appl Pharmacol. 2012 May 15;261(1):22-30. doi: 10.1016/j.taap.2012.03.004. Epub 2012 Mar 14.


Pulmonary toxicity induced by sulfur mustard and related vesicants is associated with oxidative stress. In the present studies we analyzed the role of reactive nitrogen species (RNS) generated via inducible nitric oxide synthase (iNOS) in lung injury and inflammation induced by vesicants using 2-chloroethyl ethyl sulfide (CEES) as a model. C57Bl/6 (WT) and iNOS-/- mice were sacrificed 3 days or 14 days following intratracheal administration of CEES (6 mg/kg) or control. CEES intoxication resulted in transient (3 days) increases in bronchoalveolar lavage (BAL) cell and protein content in WT, but not iNOS-/- mice. This correlated with expression of Ym1, a marker of oxidative stress in alveolar macrophages and epithelial cells. In contrast, in iNOS-/- mice, Ym1 was only observed 14 days post-exposure in enlarged alveolar macrophages, suggesting that they are alternatively activated. This is supported by findings that lung tumor necrosis factor and lipocalin Lcn2 expression, mediators involved in tissue repair were also upregulated at this time in iNOS-/- mice. Conversely, CEES-induced increases in the proinflammatory genes, monocyte chemotactic protein-1 and cyclooxygenase-2, were abrogated in iNOS-/- mice. In WT mice, CEES treatment also resulted in increases in total lung resistance and decreases in compliance in response to methacholine, effects blunted by loss of iNOS. These data demonstrate that RNS, generated via iNOS play a role in the pathogenic responses to CEES, augmenting oxidative stress and inflammation and suppressing tissue repair. Elucidating inflammatory mechanisms mediating vesicant-induced lung injury is key to the development of therapeutics to treat mustard poisoning.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Acute-Phase Proteins / genetics
  • Animals
  • Chemical Warfare Agents / toxicity
  • Female
  • Gene Expression Regulation / drug effects
  • Inflammation / chemically induced
  • Inflammation / physiopathology*
  • Lipocalin-2
  • Lipocalins / genetics
  • Lung / drug effects
  • Lung / physiopathology
  • Lung Injury / chemically induced
  • Lung Injury / physiopathology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mustard Gas / analogs & derivatives*
  • Mustard Gas / toxicity
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism*
  • Oncogene Proteins / genetics
  • Oxidative Stress / drug effects
  • Reactive Nitrogen Species / metabolism*
  • Time Factors
  • Tumor Necrosis Factor-alpha / genetics


  • Acute-Phase Proteins
  • Chemical Warfare Agents
  • Lipocalin-2
  • Lipocalins
  • Oncogene Proteins
  • Reactive Nitrogen Species
  • Tumor Necrosis Factor-alpha
  • Lcn2 protein, mouse
  • 2-chloroethyl ethyl sulfide
  • Nitric Oxide Synthase Type II
  • Mustard Gas