Adaptive response in human lymphocytes conditioned with hydrogen peroxide before irradiation with X-rays

Abstract

Cultured human lymphocytes were first exposed to a low ''conditioning'' dose of hydrogen peroxide and, subsequently, irradiated with a ''challenge'' dose of 1.5 Gy of X-rays in order to analyse the induction of an adaptive response to oxidative damage. A significant reduction in X-ray-induced chromosome damage was evident when H2O2 was given as a single 30 min pulse 24 h after setting up the cultures and the lymphocytes were exposed to X-rays at 48 h. In contrast, when the cells underwent a repeated exposure to H2O2 before irradiation the yield of aberrations was that expected from the combined treatment.