Induction of heme oxygenase-1 and adaptive protection against the induction of DNA damage after hyperbaric oxygen treatment.

Hyperbaric oxygen (HBO) treatment of human subjects (i.e. exposure to 100% oxygen at a pressure of 2.5 ATA for a total period of 3 x 20 min) caused clear and reproducible DNA damage in lymphocytes, as detected with the comet assay (single cell gel electrophoresis). Induction of DNA damage was found only after the first HBO exposure and not after further treatments of the same individuals. Furthermore, blood taken 24 h after HBO treatment was significantly protected against the induction of DNA damage by hydrogen peroxide (H(2)O(2)) in vitro, indicating that adaptation occurred due to induction of antioxidant defenses. The cells were not significantly protected against the genotoxic effects …