Mucous cell metaplasia in response to NiNP exposure in WT and T-bet-/-mice. A) Quantification of mucus producing cells at 1 or 21 days post-exposure determined using ImageJ analysis software (NIH). Data presented as the percentage of AB/PAS-positive stained area per total area. ***p < 0.001 compared to the control group of the same genotype or as indicated. All data represent mean values ± SEM of at least three measurements per lung of 5–7 mice per exposure group. B) Low magnification (10×) of AB/PAS stained lung tissue sections (open arrows) at 21 days after WT and T-bet-/- mice were exposed to a 0.1% pluronic solution or NiNP. Asterisk indicates area of fibrosis. C) High magnification (40× and 100×) of insert from 10× in ( B ). Black arrows indicate alveolar macrophages containing NiNP agglomerates.