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% O2, 5% CO2) on mitochondrial function in cultured mouse lung epithelial cells and neonatal mice. Results: In epithelial cells, 4 h 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 h exhibited a persistent global reduction in fuel utilization. In addition, neonatal mice exposed to hyperoxia for only 12 h 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. Impact: Many studies use long exposures (up to 14 days) to hyperoxia to mimic neonatal chronic lung disease. We show that even a very short exposure to hyperoxia leads to long-term cellular injury in type II-like epithelial cells. This study demonstrates that a short (4 h) period of hyperoxia has long-term residual effects on cellular metabolism. We show that neonatal mice exposed to hyperoxia for a short time (12 h) demonstrate later alveolar simplification. This work suggests that any exposure to clinical hyperoxia leads to persistent lung dysfunction.
Bibliographical noteFunding Information:
We are grateful to Dr. Ronald Mason for the generous gift of DMPO antibody. Research reported in this publication was supported by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health under award number HL139080 (to D.G.), NIH T32 HL134625 (to D.G.), the Institutional Development Award (IDeA) from the NIGMS of NIH under grant #P20GM103652 (to H.Y.), the Falk Medical Research Trust Catalyst Award (to H.Y.), and the Warren Alpert Foundation at Brown University (to P.A.D.).