Imbalance of Ly6Chi and Ly6Clo monocytes/macrophages worsens hyperoxia-induced lung injury and is rescued by IFN-gamma

This study is to examine the transcriptome of mononuclear cell populations in the neonatal lung. We investigated how acute hyperoxia-induced lung injury changes gene expression within these mononuclear populations: dendritic cells, interstitial monocytes/macrophages, and alveolar macrophages. Overall design: Litters of newborn C57BL/6 mice were identified within 6 hours of birth, mixed, and randomly assigned to hyperoxia conditions (FiO2 0.9) or normoxic control condition. Pups were euthanized after 1.5 days of hyperoxia or normoxia exposure. Mice were perfused and whole lungs were isolated then enzymatically and mechanically digested. 4 populations of mononuclear cells were identified by flow cytometry, including dendritic cell (DC, MHCIIhi CD11chi), Ly6Chi monocytes/macrophages (Ly6Chi CD11clo), Ly6Clo monocytes/macrophages (Ly6Clo CD11chi), and alveolar macrophages (AM, SiglecFhi CD11chi).