Influence of chronic exposure to low doses of γ-radiation and 90Sr on the level of DNA breaks and cell sensitivity to hydrogen peroxide in the mouse spleen

Abstract

Using comet assay, a statistically significant increase (p < 0.05) in the level of DNA breaks in spleen cells was revealed in male CBA/lac mice exposed to γ-radiation (1.7 mGy/day)
or 90Sr (150–250 Bq/day) for 210 days. The level of DNA breaks also increased under combined exposure to both γ-radiation and 90Sr (p < 0.05), but to a lesser degree than under exposure to each of these factors alone. Upon additional in vitro treatment of
spleen cells with hydrogen peroxide, the relative increase in the level of DNA breaks was smaller in cells of irradiated mice
than in the control. The ratio of the level of DNA breaks after hydrogen peroxide treatment to that before this treatment
in control mice was 4.2 ± 0.9, compared to 1.4 ± 0.6 in γ-irradiated mice, 1.9 ± 0.8 in 90Sr-irradiated mice, and 2.3 ± 0.8 in mice exposed to both γ- and 90Sr-irradiation.