Role of MIF in the mouse BPD model: impact on pulmonary phenotype and BAL total cell counts. NB MIF KO, MIF TG and WT control mice were exposed to 100% O2 for PN1-4, with recovery in RA from PN5-14 (BPD model). Representative photomicrographs of lung histology (H&E stain) of NB MIF KO, MIF TG and WT control mice exposed to RA or BPD model at PN14 (2A). The figures are illustrative of a minimum of 7 animals in each group. Alveolar size, as measured by chord length, confirmed features noted on lung histology (2B). Each bar represents the mean ± SEM of a minimum of 7 animals. BAL total cell count of NB MIF KO, MIF TG and WT control mice exposed to RA at PN14 or BPD model (2C). Each bar represents the mean ± SEM of a minimum of 5 animals. MIF +/+: wild type; MIF −/−: macrophage migration inhibitory factor knock out; MIF TG +: macrophage migration inhibitory factor (over-expressing) transgenic; BAL: bronchoalveolar lavage; BPD model: bronchopulmonary dysplasia mouse model. *P<0.05; ##P<0.0001.