Epithelial sodium channel is involved in H2S-induced acute pulmonary edema.

Acute pulmonary edema is one of the major outcomes of exposure to high levels of hydrogen sulfide (H2S). However, the mechanisms involved in H2S-induced acute pulmonary edema are still poorly understood. Therefore, the present study is designed to evaluate the role of epithelial sodium channel (ENaC) in H2S-induced acute pulmonary edema. The Sprague-Dawley rats were exposed to sublethal concentrations of inhaled H2S, then the pulmonary histological and lung epithelial cell injury were evaluated by hematoxylin-eosin staining and electron microscopy, respectively. In addition to morphological investigation, our results also revealed that H2S exposure significantly decreased the alveolar fluid clearance and increased the lung tissue wet-dry ratio. These changes were demonstrated to be associated with decreased ENaC expression. Furthermore, the extracellular-regulated protein kinases 1/2 pathway was demonstrated to be implicated in H2S-mediated ENaC expression, because PD98059, an ERK1/2 antagonist, significantly mitigated H2S-mediated ENaC down-regulation. Therefore, our results show that ENaC might represent a novel pharmacological target for the treatment of acute pulmonary edema induced by H2S and other hazardous gases.