Bronchiolitis Obliterans and Pulmonary Fibrosis after Sulfur Mustard Inhalation in Rats

Am J Respir Cell Mol Biol. 2018 Jun;58(6):696-705. doi: 10.1165/rcmb.2017-0168OC.


Inhalation of powerful chemical agents, such as sulfur mustard (SM), can have debilitating pulmonary consequences, such as bronchiolitis obliterans (BO) and parenchymal fibrosis (PF). The underlying pathogenesis of disorders after SM inhalation is not clearly understood, resulting in a paucity of effective therapies. In this study, we evaluated the role of profibrotic pathways involving transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF) in the development of BO and PF after SM inhalation injury using a rat model. Adult Sprague-Dawley rats were intubated and exposed to SM (1.0 mg/kg), then monitored daily for respiratory distress, oxygen saturation changes, and weight loss. Rats were killed at 7, 14, 21, or 28 days, and markers of injury were determined by histopathology; pulmonary function testing; and assessment of TGF-β, PDGF, and PAI-1 concentrations. Respiratory distress developed over time after SM inhalation, with progressive hypoxemia, respiratory distress, and weight loss. Histopathology confirmed the presence of both BO and PF, and both gradually worsened with time. Pulmonary function testing demonstrated a time-dependent increase in lung resistance, as well as a decrease in lung compliance. Concentrations of TGF-β, PDGF, and PAI-1 were elevated at 28 days in lung, BAL fluid, and/or plasma. Time-dependent development of BO and PF occurs in lungs of rats exposed to SM inhalation, and the elevated concentrations of TGF-β, PDGF, and PAI-1 suggest involvement of these profibrotic pathways in the aberrant remodeling after injury.

Keywords: PAI-1; bronchiolitis obliterans; lung fibrosis; sulfur mustard; transforming growth factor-β.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Inhalation
  • Animals
  • Bronchiolitis Obliterans / chemically induced*
  • Bronchiolitis Obliterans / metabolism
  • Bronchiolitis Obliterans / mortality
  • Bronchiolitis Obliterans / pathology
  • Bronchoalveolar Lavage Fluid
  • Chemical Warfare Agents / toxicity
  • Dose-Response Relationship, Drug
  • Mustard Gas / administration & dosage*
  • Mustard Gas / toxicity*
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Platelet-Derived Growth Factor / metabolism
  • Pulmonary Fibrosis / chemically induced*
  • Pulmonary Fibrosis / metabolism
  • Pulmonary Fibrosis / mortality
  • Rats, Sprague-Dawley
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism
  • Respiratory Function Tests
  • Transforming Growth Factor beta1 / metabolism
  • Weight Loss / drug effects


  • Chemical Warfare Agents
  • Plasminogen Activator Inhibitor 1
  • Platelet-Derived Growth Factor
  • Transforming Growth Factor beta1
  • Receptor, Platelet-Derived Growth Factor alpha
  • Mustard Gas