Radiation‐induced effects in the Organs of the Reproductive and Endocrine Systems of Mice

Abstract

In connection with the radioactive contamination of territories as a result of atomic explosions, the activities of enterprises for the extraction, processing and storage of radioactive materials, as well as emergency radioactive contamination, it is urgent to study the biological consequences of chronic exposure to ionizing radiation in low doses. We studied the effect of chronic gamma irradiation (10-30 cGy) on the fertility of female Af line mice, on the cytogenetic state of male germ cells, and also investigated the stability of the genome in thyroid cells. The experiments were carried out on animals from the Scientific Collection of Experimental Animals (http://www.ckp-rf.ru/usu/471933/). It was found that the chronic action of ionizing radiation in low doses leads to an increase in the fertility of female mice (20 and 30 cGy). It was found that 4 months after irradiation, the number of abnormal sperm heads and the level of micronuclei in thyroid cells were the same as in the control. In the long term after irradiation of mice at doses of 20 and 30 cGy, a decrease in the number of cells with double-stranded DNA breaks was found in the thyroid gland. Irradiation of mice at a dose of 10 cGy did not change the level of DNA fragmentation in the thyroid gland. It was shown that irradiation of animals in a chronic mode contributed to a change in the sensitivity of thyroid cells to an additional load of urethane. We found in thyroid cells after exposure to urethane a decrease in DNA double-strand breaks in control mice, whereas in irradiated animals there was an increase in DNA fragmentation in the cells. Thus, the effectiveness of chronic exposure to ionizing radiation at doses of 20 and 30 cGy was found, which was manifested in an increase in fertility in female mice and in a change in the stability of the thyroid gland cell genome. We think that in order to identify biological effects in the field of low doses of ionizing radiation, it is necessary to apply research methods at different levels of the structural organization of the organism.