title: Effects of oxygen concentration and exposure time on cultured human airway epithelial cells.
abstract: OBJECTIVE
  To distinguish the direct effects of oxygen dose and exposure time on human airway epithelial cells. We hypothesized that progressive oxygen exposure would induce cell dysfunction and inflammation in a dose-dependent manner.
  
  
  METHODS
  Interventional laboratory study.
  
  
  METHODS
  An academic medical research facility in the northeastern United States.
  
  
  METHODS
  Calu-3 human airway epithelial cell culture.
  
  
  METHODS
  Cells were cultured at a gas-liquid interface with the cells fed basolaterally with medium and grown to full confluence. The apical surfaces were then exposed to gas containing 21%, 40%, 60%, or 80% oxygen, 5% CO2, and balance nitrogen for 24 or 72 hrs.
  
  
  RESULTS
  The effects of oxygen concentration and time-induced cellular change were examined by measuring transepithelial resistance of monolayers, cell viability by trypan blue exclusion, basolateral lactate concentration, histology of monolayer cross-sections, and cytospin slides, plus interleukin (IL)-6 and IL-8 secretion in apical surface fluid. Transepithelial resistance decreased in a dose- and time-dependent manner (p < .001), whereas cell viability was reduced only at 72 hrs and in all hyperoxic groups (p < .05). IL-6 secretion was elevated in all hyperoxic groups at 24 hrs (p < .001), and both IL-6 and IL-8 levels were greater in the 40% FiO2 group compared with all other groups at 72 hrs (p < .01).
  
  
  CONCLUSIONS
  In this model, airway epithelial cells demonstrate profound concentration and time-dependent responses to hyperoxic exposure with respect to cell physiology, viability, histology, and secretion of inflammatory mediators. This model might be a valuable tool for preliminary analysis of potentially protective therapies against hyperoxia-induced airway epithelial injury.
authors.affiliation: Nemours Research Lung Center, Nemours, Alfred I. duPont Hospital for Children, Wilmington, DE, USA. yzhu@nemours.org
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
authors.forename: Thomas L
authors.initials: TL
authors.lastname: Miller
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Singhaus
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Shaffer
authors.forename: Aaron
authors.initials: A
authors.lastname: Chidekel
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods*; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000276:immunology* / Q000378:metabolism; D006801:Humans; D009511:New England; D010100:Oxygen / Q000008:administration & dosage* / Q000276:immunology* / Q000378:metabolism; D020545:Respiratory Mucosa / Q000276:immunology*; D013997:Time Factors
chemical_list: D010100:Oxygen