Progressive Lung Injury, Inflammation, and Fibrosis in Rats Following Inhalation of Sulfur Mustard

Area of Science:

• Toxicology
• Pulmonary Medicine
• Animal Models

Background:

• Sulfur mustard (SM) inhalation causes severe, progressive pulmonary injury and fibrosis in humans.
• Understanding the mechanisms of SM-induced lung damage is crucial for developing effective countermeasures.

Purpose of the Study:

• To develop and characterize a rat model of SM inhalation toxicity that accurately reflects human respiratory pathology.
• To investigate the time course and molecular mediators of SM-induced lung injury and fibrosis in this model.

Main Methods:

• Rats were exposed to varying doses of SM vapor.
• Pulmonary pathology was assessed via histopathology at different time points post-exposure.
• Bronchoalveolar lavage (BAL) fluid analysis was performed to quantify inflammatory cells and proteins.
• Expression of key inflammatory and profibrotic markers was measured.

Main Results:

• SM inhalation caused dose-dependent respiratory tract damage, including inflammation, edema, and epithelial necrosis.
• The pathological response was biphasic, with initial injury followed by delayed, more severe fibrosis at 28 days.
• Increased levels of inflammatory mediators (RAGE, HMGB-1, TNF-α, iNOS, Gal-3) and profibrotic markers were observed.
• Oxidative stress, indicated by HO-1 expression, was associated with SM-induced lung inflammation.

Conclusions:

• The developed rat model accurately replicates the biphasic pulmonary pathology and fibrosis seen in human SM inhalation.
• This model provides a valuable platform for mechanistic studies of SM lung toxicity.
• The model can be utilized for screening and identifying potential therapeutic agents to mitigate SM-induced lung injury.