Role of MIF in the mouse BPD model: impact on protein expression of vascular factors and their receptors. 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). The mice were sacrificed at PN14. Ang1, Ang2, Tie2, VEGF-A, and VEGFR1 proteins, with β-actin as controls, were detected by western blotting (4A). The relative density of VEGF -A and it’s receptor -R1 as well as Ang1 and Ang2 and their receptor Tie2 (4B and 4C) were quantified by densitometry. The figure is representative of n=3 mice per group. MIF +/+: wild type; MIF −/−: macrophage migration inhibitory factor knock out; MIF TG +: macrophage migration inhibitory factor (over-expressing) transgenic; BPD: bronchopulmonary dysplasia mouse model. VEGF: vascular endothelial growth factor; R: receptor; Ang: angiopoietin; β-actin: beta-actin. ##P<0.001, #P≤0.01, *P<0.05.