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Hyperoxia induces DNA damage in mammalian cells
M A Cacciuttolo1, L Trinh, J A Lumpkin
1Chemical and Biochemical Engineering Program, University of Maryland Baltimore County, MD 21228.
Free Radical Biology & Medicine
|March 1, 1993
Summary
High oxygen levels (hyperoxia) directly cause DNA strand breaks in cells, independent of chemical free radical systems. This cellular damage is comparable to hydrogen peroxide exposure.
Area of Science:
- Cell Biology
- Biochemistry
- Oxidative Stress
Background:
- Oxygen-derived free radicals are implicated in cellular damage.
- Previous studies often used chemical systems to induce oxidative stress.
- The direct impact of dissolved oxygen tension on DNA integrity requires further investigation.
Purpose of the Study:
- To quantify DNA strand breaks as a function of dissolved oxygen tension.
- To investigate the effects of hyperoxia on cellular metabolic functions.
- To compare hyperoxia-induced DNA damage with that induced by hydrogen peroxide.
Main Methods:
- Measuring DNA strand breaks using a sensitive technique in a bioreactor.
- Exposing cells to varying dissolved oxygen levels (10% to 476%) at mid-exponential growth phase.
- Assessing glucose consumption, lactate production, and cell growth rates under hyperoxic conditions.
Main Results:
- Hyperoxia monotonically increased DNA strand breakage at all tested oxygen levels.
- Elevated oxygen levels impacted cellular metabolic functions, including glucose consumption and lactate production.
- DNA strand breakage from 200% dissolved oxygen was comparable to 4.2 microM hydrogen peroxide exposure.
Conclusions:
- Dissolved oxygen tension directly correlates with DNA strand breakage in cells.
- Hyperoxia induces DNA damage and affects cellular metabolism.
- This study establishes a link between hyperoxia and DNA damage, distinct from chemical radical generation.