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% 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.

Automated summary

This research reveals that even a very short exposure to high oxygen concentrations can lead to long-term cellular injury in lung epithelial cells, affecting mitochondrial function and alveolarization. The study highlights the long-term residual effects of a short period of hyperoxia on cellular metabolism and the development of alveolar simplification in neonatal mice. The findings suggest that any exposure to clinical hyperoxia can result in persistent lung dysfunction.