Oxidative stress reactions in rats with pulmonary injuries induced by sulfur mustard (1 LD50).

Objective: Sulfur mustard (SM) is an important chemical warfare agent. The mechanisms underlying SM toxicity have not been completely elucidated. However, oxidative stress and the subsequent damage to macromolecules have been considered ascrucial steps in SM toxicity. In this study, a rat model of SM-induced acute pulmonary injury was established using an equal toxicity dose (1LD₅₀). This study employed two methods to directly compare oxidative stress indices in serum enzymes and the epithelial cells of the alveolar septa.

Methods: Male Sprague-Dawley rats were randomly divided into intraperitoneal SM, intraperitoneal propylene glycol control, tracheal SM, tracheal propylene glycol control, and control groups. SM-induced serum enzyme levels and protein expression in the epithelial cells of the alveolar septa were measured using enzyme-linked immunosorbent assay and immunohistochemistry.

Results: Serum levels of superoxide dismutase, catalase, and glutathione peroxidase were upregulated in the intraperitoneal SM group compared with those in the tracheal SM group. Positive expression ratios of CuZn-superoxide dismutase, Mn-superoxide dismutase, paraoxonase-1, and apolipoprotein-1 proteins in the epithelial cells of the alveolar septa in the intraperitoneal SM group were elevated compared with those in the tracheal SM group.

Conclusion: Under SM (1LD₅₀) exposure, there were significantly higher serum enzyme levels and protein expressions in the epithelial cells of the alveolar septa of rats injected with SM intraperitoneally compared with SM administered by intratracheal instillation. The results demonstrated that the differences in oxidative stress indices at the molecular level in SM-induced pulmonary injury were dependent on the route of exposure.