DETECTION OF DNA-DAMAGE AFTER HYPERBARIC-OXYGEN (HBO) THERAPY

Hyperbaric oxygen (HBO) therapy is successfully used for the treatment of a variety of conditions, However, exposure to high concentrations of oxygen is known to induce damage to cells, possibly due to an incre ased oxygen radical production, As reactive oxygen species also cause DNA damage, we investigated the DNA-damaging effect of HBO with the al kaline version of the single cell gel test (comet assay), Oxidative DN A base modifications were determined by converting oxidized DNA bases to strand breaks using bacterial formamidopyrimidine-DNA glycosylase ( FPG), a DNA repair enzyme, which specifically nicks DNA at sites of 8- oxo-guanines and formamidopyrimidines. HBO treatment under therapeutic conditions clearly and reproducibly induced DNA damage in leukocytes of all test subjects investigated, Increased DNA damage was found imme diately at the end of the treatment, while 24 h later, no effect was f ound, Using FPG protein we detected significant oxidative base damage after HBO treatment, DNA damage was detected only after the first trea tment and not after further treatments under the same conditions, indi cating an increase in antioxidant defences, DNA damage did not occur w hen the HBO treatment was started with a reduced treatment time which was then increased stepwise.