DETERMINATION OF THE OCCURENCE OF NUCLEAR ANOMALIES IN DANIO RERIO PERIPHERAL BLOOD ERYTH- ROCYTES DEPENDING ON THE DOSE OF IONIZING RADIATION
Ionizing radiation induces double-stranded breaks in the DNA structure, following by the formation of dicentric chromosomes. With the passage of subsequent postradiation mitoses, dicentric chromosomes are unevenly distributed to the poles of the cell, as a result of which nuclear anomalies of various types are formed, distinguishable at the light-optical level. The aim of this study was to assess the occurrence of nuclear anomalies in the peripheral blood erythrocytes of freshwater fish Danio rerio after exposure to ionizing radiation, as well as to assess the possibility of using these organisms as model animals in radiobiological studies. To determine the frequency of occurrence of nuclear anomalies in peripheral blood erythrocytes of freshwater fish Danio rerio, fish were exposed to X-ray radiation at doses of 0.0, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0 Gy. 48 hours after irradiation in fish peripheral blood erythrocytes by light microscopy, four types of nuclear anomalies were identified: micronuclei, nuclear protrusions, nucleoplasmic bridges, dumbbell-shaped nuclei. The frequency of detection of micronuclei and nuclear protrusions was found to be dose-dependent (r = 0.9245, p < 0.05 and r = 0.9062, p < 0.05 respectively), while the appearance of nucleoplasmic bridges and dumbbell-shaped nuclei did not correlate with the dose. More than that, the frequencies of micronuclei and nuclear protrusions detected after irradiation of fish at doses of more than 4 Gy (4.0, 6.0 and 8.0 Gy) significantly differed from the control values. Thus, Danio rerio can be used as a laboratory test system for radiobiological research, for example, to determine the effect of the developed radioprotectors and radiosensitizers, despite the extreme radioresistance of these organisms. It is advisable to use micronuclei or nuclear protrusions as cell markers, given, however, that the identification of these markers will allow detecting radiation exposure only in doses above 4 Gy.