Fig. 2.

Hyperoxia downregulates Ang1-Tie2 signaling in developing lungs. NB WT mice were exposed to hyperoxia from PN day 1−4. a Western blots showing decreased expression of Phospho-Tie2, Tie2 and Ang1. b Densitometric analysis was completed and the expression of detected proteins was normalized to β-actin. c, d MLE12 cells were incubated with or without the presence of hyperoxia (95% O₂) for 24 h. Western blot analysis showed downregulation of Tie2 and Ang1, quantified in D. e, f Western blot showing decreased Tie2 and Ang1 expression in MLE12 cells, which were exposed to different concentrations of oxygen (21, 40, 60, and 95%) for 48 h, quantified in F. g, h Freshly isolated type 2 epithelial cells were incubated in absence and presence of HYP (95% O₂) for 4 h and western blot performed for Ang1 and Tie2 expression, quantified in H (n = 1). WT: Wild-type; NB: newborn; PN: postnatal; Ang1: Angiopoietin 1; RA: room air; HYP: hyperoxia. Values are means + SEM of a minimum of four observations (in vitro experiments, unless otherwise stated) or four animals (in vivo experiments) in each group. *P <0.05, **P <0.01, ***P <0.01, compared with controls, 1-way ANOVA