Propidium iodide (PI) as indicator of lung cell injury.

<p>Representative images from the Control (A) and ZEEP/≥2xH group (B) groups showing PI+ nuclei (red cells, white arrows). Fluorescence intensity increases ~20-fold when PI binds to nucleic acids. ZEEP/≥2xH group was ventilated with zero end-expiratory pressure until elastance at least doubled; control group was not ventilated.