Bronchiolitis Obliterans and Pulmonary Fibrosis after Sulfur Mustard Inhalation in Rats

Area of Science:

• Pulmonary toxicology
• Chemical injury research
• Fibrosis pathogenesis

Background:

• Sulfur mustard (SM) inhalation leads to severe lung damage, including bronchiolitis obliterans (BO) and parenchymal fibrosis (PF).
• The exact mechanisms driving SM-induced lung pathology are poorly understood, limiting effective treatment options.
• Profibrotic pathways, such as those involving transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF), are implicated in lung remodeling.

Purpose of the Study:

• To investigate the role of TGF-β and PDGF in the development of BO and PF following SM inhalation injury.
• To characterize the time-dependent pulmonary consequences of SM exposure in a rat model.
• To assess the correlation between elevated profibrotic markers and lung injury progression.

Main Methods:

• Adult Sprague-Dawley rats were exposed to sulfur mustard (SM).
• Animals were monitored for respiratory distress, oxygen saturation, and weight loss.
• Histopathology, pulmonary function tests, and measurement of TGF-β, PDGF, and PAI-1 levels were performed at various time points (7, 14, 21, 28 days).

Main Results:

• SM inhalation induced progressive respiratory distress, hypoxemia, and weight loss over 28 days.
• Histopathology confirmed the development and worsening of BO and PF.
• Pulmonary function tests showed increased lung resistance and decreased lung compliance.
• Elevated levels of TGF-β, PDGF, and PAI-1 were detected in lung tissue, BAL fluid, and/or plasma at 28 days post-exposure.

Conclusions:

• Sulfur mustard inhalation leads to a time-dependent development of bronchiolitis obliterans and parenchymal fibrosis in rats.
• Increased concentrations of TGF-β, PDGF, and PAI-1 suggest their critical involvement in the profibrotic remodeling process after SM injury.
• These findings highlight potential therapeutic targets for mitigating SM-induced lung damage.