title: Moderate hyperoxia (40%) increases antioxidant levels in mouse tissue.
abstract: BACKGROUND
  Oxygen is routinely administered to patients to improve clinical outcome. Since studies have shown that administering 100% oxygen can cause unwanted side effects, intermediate concentrations of 40% oxygen are used in clinical practice. In this study, we examined whether the breathing of 40% oxygen causes beneficial effects upon tissue levels of antioxidants such as vitamin E, vitamin C, and glutathione.
  
  
  METHODS
  Four-month-old mice were separated into two groups: control (n = 11) and experimental (n = 11). The treatment group was administered 40% oxygen for 10 days. Brain, heart, lung, liver, testes, and skeletal muscle were harvested and tissue antioxidant levels were determined by HPLC.
  
  
  RESULTS
  Vitamin E concentrations were higher in brain, heart, lung, liver, and testes of the treatment group (P < 0.05). Glutathione concentrations were higher in the lung tissue only (P < 0.05). No differences were found in vitamin C levels.
  
  
  CONCLUSIONS
  The data suggest that mice respond to oxidative stress by increasing tissue vitamin E incorporation and cellular synthesis of glutathione in the lung when exposed to moderate levels (40%) of hyperoxia.
authors.affiliation: Department of Surgery, University of California Davis, Sacramento, California 95817, USA. eugenes.lee@ucdmc.ucdavis.edu
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Lee
authors.forename: W Ed
authors.initials: WE
authors.lastname: Smith
authors.forename: Hung T
authors.initials: HT
authors.lastname: Quach
authors.forename: Bryan D
authors.initials: BD
authors.lastname: Jones
authors.forename: Steven M
authors.initials: SM
authors.lastname: Santilli
authors.forename: Govind T
authors.initials: GT
authors.lastname: Vatassery
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D005978:Glutathione / Q000378:metabolism*; D018496:Hyperoxia / Q000378:metabolism / Q000503:physiopathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009994:Osmolar Concentration; D012720:Severity of Illness Index; D014018:Tissue Distribution; D014810:Vitamin E / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D014810:Vitamin E; D005978:Glutathione; D001205:Ascorbic Acid