Markers of human extraembryonal cells individual radiosensitivity in vitro

Background: Genotoxic effects of ionizing radiation in early stages of human embryonic development can lead to fatal consequences. At the same time, the radiosensitivity of human embryonic and extraembryonic cells is still poorly studied. In this study, the analysis of DNA double-strand break repair effectiveness in human extraembryonal fibroblasts was carried out. Materials and methods. Extraembryonic human fibroblasts was irradiated by 1 Gy gamma-rays using Theratron Equinox (Cancer Research Institute, Tomsk). The level of DNA double strand breaks was assessed using γH2AX foci. Frequency of cytogenetic damage was assessed using micronucleus test conducted with FISH as a frequency of centromere-negative micronuclei. Results. No significant correlation was observed between both endogenous and residual levels of radiation-induced γH2AX foci and frequency of micronuclei after irradiation. It is suggested to be a result of the specificity of extraembryonal fibroblast radiation-induced response. The spontaneous frequency of centromere-negative micronuclei correlated with radiation-induced frequency of centromere-negative micronuclei. Conclusion. It was shown that human extraembryonal fibroblasts ability to repair radiation-induced DNA damage is likely to be reflected by the repair of spontaneous DNA double strand breaks.

γH2AX foci, micronuclei, DNA double-strand breaks, DNA repair, extraembryonic fibroblasts, individual radiosensitivity