Sheep radiosensitivity modification

Acute exposure of sheep to g-radiation at sublethal (2 Gy) and lethal (6 Gy) doses following nine-month prolonged irradiation of the animals with doses of 0,5 and 0,1 Gy, respectively, was found to result in no pronounced activation of free radical lipid peroxidation. Analysis of animals blood plasma showed decrease in the spontaneous chemiluminescence intensity, tendency towards an increase in the level of malonic dialdehyde and weak change in concentration of diene and triene conjugates (DC and TC), as well as a-tocopherol and retinol. On the contrary, a single acute exposure of the sheep to g-radiation at 2 and 6 Gy caused increase in the rate of free radical lipid peroxidation in plasma. When animals developed a radiation-induced abnormalities, increased levels of spontaneous chemiluminescence intensity, concentration of malonic dialdehyde, DC, TC and α-tocopherol were registered with simultaneous reduction in the retinol level. A comparative analysis of obtained data on the rate of free radical lipid peroxidation in the blood plasma and survival of sheep showed that prolonged exposure at doses of 0,1 and 0,5 Gy modifies response of animals to subsequent acute g-radiation exposure at sublethal and lethal doses.