AQP5 and acute respiratory distress syndrome: Moreover, both Western blot and immunohistochemical analysis showed that the BNx-induced significant decrease in pulmonary AQP-5 expression was obviously restored by oral administration of AST-120 (Figure 4), suggesting that IS accumulation in lung tissue may play pivotal roles in the pathogenesis of ALI through dysregulation of pulmonary AQP-5 expressed in alveolar epithelial cells.