Figure 6: Lung macrophage contents in 28 d mice. Animals were exposed to room air or 85% O2 followed by room air as indicated. (a) Representative photomicrographs (100x and 400x). (b) Inflation-fixed sections were stained with anti-Mac3 antibodies and macrophages (indicated by arrowheads) were counted in 5 fields per slide ( mice per group), averaged, and expressed per high-power field (HPF). Data were analyzed by Student’s test. (* versus RA).