Cyclic stretch induced oxidative injury increases alveolar permeability via ERK-NF-κB signaling

The mechanisms underIying cyclic-stretch induced increase in pulmonary alveolar epithelial permeability are not yet fully elucidated. Here we demonstrate high levels of superoxide and nitric oxide in type 1 alveolar epithelial cells that were stretched at 12 and 37% change in surface area for different time durations. Cyclic stretch induced increase in permeability was decreased by the supeoxide scavenger Tiron and by the NF-κB inhibitor MG132. Furthermore, cyclic stretch increased the activation of the NF-κB signaling pathway which was significantly decreased with ERK inhibitor U0126. These data suggest that cyclic stretch induces oxidative stress, which mediates increases in alveolar epithelial monolayer permeability via NF-κB activation and ERK phosphorylation.