In vivo antioxidant gene expression in human airway epithelium of normal individuals exposed to 100% O2

S. C. Erzurum, C. Danel, A. Gillissen, C. S. Chu, B. C. Trapnell, Ronald Crystal

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Abstract

Human bronchial epithelium is exquisitely sensitive to high O2 levels, with tracheobronchitis usually developing after 12 h of exposure to 100% O2. To evaluate whether this vulnerability results from inability of the bronchial epithelium to provide adequate antioxidant protection, we quantified antioxidant gene expression in bronchial epithelium of normal volunteers at baseline and after exposure to 100% O2 in vivo. After 14.8 ± 0.2 h of 100% O2, 24 of 33 individuals had evidence of tracheobronchitis. Baseline gene expression of CuZn superoxide dismutase (SOD), MnSOD, and catalase in bronchial epithelium was very low (CuZnSOD 4.1 ± 0.8 transcripts/cell, MnSOD 5.1 ± 0.9, catalase 1.3 ± 0.2), with control γ- actin expression relatively abundant (50 ± 6 transcripts/cell). Importantly, despite 100% O2 exposure sufficient to cause tracheobronchitis in most individuals, antioxidant mRNA transcripts/cell in bronchial epithelium did not increase (P > 0.5). Catalase activity in bronchial epithelium did not change after exposure to hyperoxia (P > 0.05). Total SOD activity increased mildly (P < 0.01) but not sufficiently to protect the epithelium. Together, the very low levels of expression of intracellular antioxidant enzymes and the inability to upregulate expression at the mRNA level with oxidant stress likely have a role in human airway epithelium susceptibility to hyperoxia.

Original languageEnglish
Pages (from-to)1256-1262
Number of pages7
JournalJournal of Applied Physiology
Volume75
Issue number3
Publication statusPublished - 1 Jan 1993
Externally publishedYes

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Keywords

  • catalase
  • hyperoxia
  • messenger ribonucleic acid
  • quantification
  • superoxide dismutase

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Erzurum, S. C., Danel, C., Gillissen, A., Chu, C. S., Trapnell, B. C., & Crystal, R. (1993). In vivo antioxidant gene expression in human airway epithelium of normal individuals exposed to 100% O2. Journal of Applied Physiology, 75(3), 1256-1262.