Radiosensitivity of Ehrlich Ascites Tumour Cells

Summary

Non-synchronized cell populations of ELD ascites tumour cells were pulse-labelled and x-irradiated in vitro with 125 R, 250 R and 500 R. The cells were grown in vivo in C3H/He Jax mice, and harvested at 2-hour intervals. Chromosome damage was scored at metaphase. Mitotic delay and cell survival were also studied in relation to chromosome aberrations. Pre-mitotic interphase death was not observed, whereas a significant decrease in cell number, related to the dose, was found after the first mitotic division. Mitotic inhibition, proportional to the dose, was observed after irradiation, and G₂ was found to be the period most delayed. Chromatid aberrations were scored in unlabelled and labelled metaphases representing cells irradiated at different stages of S and G₂. The results clearly demonstrated that G₂ was the most sensitive period. Furthermore, cells irradiated during early and middle G₂ were more sensitive than those irradiated at late G₂; and cells from early S were more sensitive than those from late S.