Short exposure to hyperoxia causes cultured lung epithelial cell mitochondrial dysregulation and alveolar simplification in mice

BACKGROUND: Prolonged exposure to high oxygen concentrations in premature infants, although lifesaving, can induce lung oxidative stress and increase the risk of developing BPD, a form of chronic lung disease. The lung alveolar epithelium is damaged by sustained hyperoxia, causing oxidative stress and alveolar simplification, however, it is unclear what duration of exposure to hyperoxia negatively impacts cellular function. METHODS: Here we investigated the role of a very short exposure to hyperoxia (95% O(2), 5% CO(2)) on mitochondrial function in cultured mouse lung epithelial cells and neonatal mice. RESULTS: In epithelial cells, 4 hours of hyperoxia reduced oxidative phosphorylation, respiratory complex I and IV activity, utilization of mitochondrial metabolites, and caused mitochondria to form elongated tubular networks. Cells allowed to recover in air for 24 hours exhibited a persistent global reduction in fuel utilization. In addition, neonatal mice exposed to hyperoxia for only 12 hours demonstrated alveolar simplification at postnatal day 14. CONCLUSION: A short exposure to hyperoxia leads to changes in lung cell mitochondrial metabolism and dynamics, and has a long term impact on alveolarization. These findings may help inform our understanding and treatment of chronic lung disease.