Alterations in Apoptotic Cell Populations, Protein Markers, and Gene Expression Patterns in Rats with Sulfur Mustard-induced Pulmonary Injuries.

Sulfur mustard (SM) is a potent chemical warfare agent that causes severe cutaneous, ocular, and pulmonary injuries, with respiratory tract damage being the most life-threatening. Despite its well-documented toxicity, the cellular mechanisms driving SM-induced apoptosis remain poorly understood. This study seeks to elucidate the apoptotic pathways involved in SM-induced pulmonary injury using a rat model. We induced acute lung injury through two delivery methods: intraperitoneal injection (8 mg/kg) and intratracheal instillation (2 mg/kg) of SM, with both doses representing 1 LD50. We assessed apoptosis-related proteins and gene expression through TUNEL staining, immunohistochemistry, and quantitative real-time PCR analyses. Intraperitoneal administration of SM resulted in significantly elevated expression of apoptotic markers including annexin A1, annexin A2, cytochrome C, caspase-12, and JNK3, in alveolar epithelial cells compared to intratracheal delivery. Both TUNEL assays and immunohistochemical staining confirmed these findings. These results indicate that intraperitoneal SM exposure triggers more severe apoptotic responses in alveolar epithelial cells than intratracheal exposure at equivalent doses. These findings demonstrate that intraperitoneal models can effectively identify apoptosis-related molecular targets suitable for therapeutic development.