Assessment of adrenaline-induced DNA damage in whole blood cells with the comet assay

Harmful effects of elevated levels of catecholamines are mediated by various mechanisms, including gene transcription and formation of oxidation products. The aim of this study was to see whether the molecular mechanisms underlying the damaging action of adrenaline on DNA are mediated by reactive oxygen species (ROS). To do that, we exposed human whole blood cells to 10 μmol L^-1adrenaline or 50 μmol L^-1H₂O₂(used as positive control) that were separately pre-treated or post-treated with 500 μmol L^-1of quercetin, a scavenger of free radicals. Quercetin significantly reduced DNA damage in both pre- and post-treatment protocols, which suggests that adrenaline mainly acts via the production of ROS. This mechanism is also supported by gradual lowering of adrenaline and H₂O₂-induced DNA damage 15, 30, 45, and 60 min after treatment. Our results clearly show that DNA repair mechanisms are rather effective against ROS-mediated DNA damage induced by adrenaline.