[Hematopoietic dynamics in mammals under combined radiation exposures (mathematical modelling)]

The mathematical models describing the dynamics of hemopoiesis in the mammals exposed to a combination of chronic irradiation are devised and studied. The models reproduce the increased radiosensitivity of the systems of thrombocytopoiesis, erythropoiesis and lymphopoiesis in the animals resulting from prolonged radiation exposure. Succeeding acute radiation exposure causes a more severe damage of the above-mentioned systems than it occurs for the species not being previously exposed to radiation. The model of granulocytopoiesis simulates both the decrease and the increase in radiosensitivity of this system due to the effect of chronic exposure using low and somewhat higher radiation doses, respectively. The postchronic acute radiation exposure has respectively the decreased or increased damaging effect. Within the limits of the models an interpretation of these effects is suggested. The results of modelling have an important theoretical significance in studies of the mechanisms of an effect of small doses of radiation on the mammalian organism as well as point to the perspectives of simulation experiments when evaluating the real radiation risks during long-term space missions.