Influence of age and gender in response to γ-radiation in Portuguese individuals using chromosomal aberration assay – Preliminary findings

Cytogenetic indicators are widely used in radiobiology to evaluate effects of ionizing radiation since dicentric chromosomes (Dic) are almost exclusively induced by ionizing radiation, and spontaneous frequency of Dic is very low in the healthy general population (about one Dic per 1000 cells). A particular interest of biodosimetry has been not only to obtain absorbed dose estimates using adequate calibration curves, under the assumption that all individuals respond equally to radiation-induced chromosome aberrations, but also to find a way to demonstrate inter-individual radiosensitivity and a possible correlation with age and gender.Thus, the objective of this preliminary work was the evaluation of the influence of age and gender on the outcome of cytogenetic biomarkers after γ-irradiation. Samples of peripheral blood lymphocytes from six healthy, non-smoker, donors from both genders (three men and three women), in the range of 20 to 49 years, were irradiated with doses from 0 Gy to 3 Gy air kerma, using a 60Co gamma rays source with a dose rate from 170–180 mGy/min.A clear dose-dependent increase in terms of aberrant cells excluding gaps (ACEG) and Dic was observed for all donors. Our preliminary results suggest, in the higher dose level evaluated (3 Gy), a larger intervariability among individuals for Dic, with females apparently more sensitive than males (P<0.05). Considering the different age groups, male donors showed a decrease, with age, for Dic and ACEG at the higher dose and also, for the background level, in case of ACEG.Future work will consider the study of more individuals, from both genders and different ages, in order to verify if this tendency persists and to enable the implementation of a dose-response calibration curve at Instituto Tecnológico e Nuclear for the Portuguese population, to quantify the biological dose in case of a radiological accident or emergency.