Seawater induces apoptosis in alveolar epithelial cells via the Fas/FasL-mediated pathway

► Fas, FasL, and cleaved caspase-8 and caspase-3 were up-regulated in the rat lungs exposed to seawater. ► Seawater-induced human lung alveolar epithelial A549 cell apoptosis was concentration and time dependent, and seawater increased the expression of Fas, FasL, and cleaved caspase-8 and caspase-3 in A549 cells. FasL-neutralising antibody (NOK-2) or caspase-8 inhibitor (Z-IETD-FMK) resulted in a decrease of seawater-induced A549 cell apoptosis. ► Seawater similarly produced a significant increase in rat alveolar type II cell apoptosis and expression of Fas and cleaved caspase-8. ► The Fas/FasL pathway involved in AEC apoptosis could be important in the pathogenesis of seawater-induced acute lung injury (SW-ALI).