The influence of dose rate on the lethal and mutagenic effects of X-rays in proliferating L5178Y cells differing in radiation sensitivity

• Published in: International journal of radiation biology and related studies in physics, chemistry and medicine Vol. 47; no. 5; p. 553
• Main Authors: Evans, H H, Horng, M F, Mencl, J, Glazier, K G, Beer, J Z
• Format: Journal Article
• Language: English
• Published: England 01.01.1985
• Subjects: Animals; Cell Line; Cell Survival - radiation effects; Dose-Response Relationship, Radiation; In Vitro Techniques; Leukemia L5178 - pathology; Leukemia, Experimental - pathology; Mice; Mutation; Radiation Genetics; Radiation Tolerance; Time Factors
• ISSN: 0020-7616
• DOI: 10.1080/09553008514550781

The lethal and mutagenic effects of ionizing radiation delivered at high (53 Gy/h) and low (0.02 Gy/h) dose rates were measured in two closely related strains of mouse lymphoma L5178Y cells differing in radiation sensitivity (LY-R and LY-S). Strain LY-R was more resistant to the lethal effects of radiation than strain LY-S when exposed at either the high or low dose rate. The survival of strain LY-R was markedly enhanced by the reduction in dose rate. The dose-rate dependence of the survival of strain LY-S was less clear, because of the biphasic nature of its survival curve following low dose-rate radiation. However, if the initial slope of the low dose-rate survival curve is compared to the slope of the high dose-rate survival curve for strain LY-S, only a slight increase in survival at the low dose rate is apparent. Although more sensitive to the lethal effects of radiation, strain LY-S was less mutable at the hypoxanthine/guanine phosphoribosyl transferase locus by both low dose-rate and high dose-rate radiation than strain LY-R. Little dose-rate dependence was exhibited by either strain with regard to the mutagenic effects of radiation. Thus, for strain LY-R, which showed marked dose-rate dependence for survival but not for mutation, the ratio of mutational to lethal lesions was much greater following exposure to low dose-rate than to high dose-rate radiation.