Induction of single-strand breaks in lymphocyte DNA of rats exposed to hyperoxia

A modified technique of alkaline filter elution was used to evaluate single-strand breaks (SSB) as a measure of DNA lesions in lymphocytes of male Wistar rats exposed to 60 or 80 vol% oxygen, over 23 h/day and for 6 or 5 days, respectively. An acceleration of elution was observed with samples from experiments at both increased levels of oxygen. With proteinase K treatment, a twofold increase in elution rates after exposure to 60 vol% oxygen and a threefold increase at 80 vol% oxygen were indicative of increased occurrence of SSB. This is explained by an involvement of reactive oxygen species in DNA damage under elevated oxygen levels.