STUDY THE EFFECTS OF IONIZING RADIATION ON THE LEVEL OF CHROMOSOME INSTABILITY IN HUMAN SOMATIC CELLS DURING THE DEVELOPMENT OF TUMOR-INDUCED BYSTANDER EFFECT

Abstract

Objective. to determine the impact of the irradiated in vitro blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) on the level of chromosomal instability in peripheral blood lymphocytes (PBL) from healthy persons during the development of tumor-induced bystander effect. Materials and methods. Separate and joint cultivation of PBL from healthy persons (cells-bystanders) together with blood cells from CLL patients irradiated in vitro at the G0 stage of the mitotic cycle by γ-quanta 137Cs in a dose of 0.5 Gy 137Cs (cells-inductors) was used. For joint cultivation our own model system for co-cultivation of PBL from individuals of different sex, designed by us to investigate the bystander effects at the cytogenetic level was used. Traditional cytogenetic analysis of uniformly painted chromosomes with group karyotyping was performed. The frequency of chromosome aberrations in cells-inductors and cells-bystanders as the markers of chromosome instability were determined. Results. Found that at co-cultivation of PBL from healthy individuals with irradiated blood cells from CLL patients the middle group frequency of chromosome aberrations in the bystander cells (5.18 ± 0.51 per 100 metaphases, p < 0.001) was statistically significant higher than its background level determined at a separate cultivaton (1.52 ± 0.30 per 100 metaphases), and at co-cultivation with non-irradiated blood cells from CLL patients (3.31 ± 0.50 per 100 metaphases, p < 0.01). Conclusions. Co-cultivation of in vitro irradiated blood cells from CLL patients with PBL from healthy persons leads to an increase in the level of chromosome instability in the bystander cells due to synergism between tumor-induced and radiation-induced bystander effects. Key words: human peripheral blood lymphocytes, B-cell chronic lymphocytic leukemia, ionizing radiation, chromosomal instability, tumor-induced bystander effect.