Short-term hyperoxia induced mitochondrial respiratory chain complexes dysfunction and oxidative stress in lung of rats

BackgroundOxygen therapy is an alternative for many patients with hypoxemia. However, this practice can be dangerous as oxygen is closely associated with the development of oxidative stress.MethodsMale Wistar rats were exposed to hyperoxia with a 40% fraction of inspired oxygen (FIO2) and hyperoxia (FIO2 = 60%) for 120 min. Blood and lung tissue samples were collected for gas, oxidative stress, and inflammatory analyses.ResultsHyperoxia (FIO2 = 60%) increased PaCO2 and PaO2, decreased blood pH and caused thrombocytopenia and lymphocytosis. In lung tissue, neutrophil infiltration, nitric oxide concentration, carbonyl protein formation and the activity of complexes I and II of the mitochondrial respiratory chain increased. FIO2 = 60% decreased SOD activity and caused several histologic changes.ConclusionIn conclusion, we have experimentally demonstrated that short-term exposure to high FIO2 can cause oxidative stress in the lung.