<p>A. Myeloperoxidase (MPO) immunostaining. 20× Magnification. MPO containing cells stain brown. <b>Left panel</b>: 2CLPAdHSP, <b>Right panel</b>: 2CLPPBS. TUNEL and MPO double staining. 40× Magnification. <b>Left panel</b>: Myeloperoxidase (MPO) Immunostaining, MPO containing cells stain brown. <b>Right panel</b>: TUNEL fluorescent staining. TUNEL positive cells are green. White arrows depict apoptotic neutrophils – brown staining for MPO and green for TUNEL. Yellow arrows depict apoptotic cells that are negative for MPO but positive for TUNEL. Red arrows depict nuclei stained for dapi –showing the orientation of the slide. Black arrows depict MPO-positive cells that were not apoptotic. TUNEL and Aquaporin 5 (AQP5) double staining. AQP5 – a specific marker for alveolar type I cells. 40× magnification. Left panel: AQP5 immunostaining, AQP5 containing cell stain brown. Right panel: TUNEL fluorescent staining. TUNEL positive cells are green. Red arrows indicate positive staining of alveolar type I cells (both AQP5 and TUNEL). Yellow arrows indicate alveolar type II cells that are negatively stained for AQP5 and positively stained for TUNEL.</p
