Cytogenetic changes in liquidators of the consequences of the Chernobyl accident resident in Armenia

It is known that one of the first and direct signs of the effect of ionizing radiation on a cell is the destabilization of chromosomes. Radiation-induced instability of the genome arises, with which the long-term consequences of ionizing radiation are associated mutagenesis, carcinogenesis, aging. Cytogenetic examination included analysis of chromosomes with Giemsa staining. The unit of proliferative activity of phytohemagglutinin-stimulated lymphocytes is the number of metaphases per 0.5 ml of culture suspension obtained after treatment with 1.2 ml of whole blood. The analysis took chromosome plates strictly at the metaphase stage of cell division (degree of chromosome helixing of at least 20%). Studies have shown that the chromosome apparatus of peripheral blood lymphocytes in liquidators has changed significantly in dynamics. These changes also depend on the time elapsed after irradiation (the remoteness of the event). Since 1987 the frequency of chromosomal aberrations (HA) was more than 2-2.5 times higher than the spontaneous level. By 2005-2006 the average number of chromosome aberrations reached 15.34 ± 2.52. According to the types of aberrations, chromatid and chromosomal (single and double DNA breaks) were mainly recorded, and since 1995, exchange aberrations were recorded. In liquidators, dicentrics and rings, which are considered biomarkers of ionizing radiation, were not found. Using the methods of logarithmic, exponential, polynomial regression, equations were obtained that describe the change in cytogenetic indicators in dynamics, where x is the number of years after the Chernobyl accident, and y1, y2, y3, y4 are chromosome aberrations (1), proliferative activity (2), single (3) and double (4) DNA breaks. Summarizing the results of cytogenetic studies in Armenian liquidators, we can clearlstate that the instability of the peripheral blood lymphocyte genome is quite pronounced and, although in the long term there is a tendency to normalization of indicators (chromosomal aberrations and proliferative activity), nevertheless, these indicators significantly differ from the control group.