Speaker
Prof.
Lyudmila Shishkina
(no)
Description
Up to now the question is discussed dose or dose rate is the more significant for the development of biological consequences under the irradiation of animals especially at low doses. Earlier in laboratory experiments and investigations on rodents caught at areas with different levels of the radioactive contamination the high sensitivity of the lipid peroxidation (LPO) regulatory system parameters in tissues of mice to the ionizing radiation action at the low doses was shown.
Parameters of the LPO regulatory system in murine tissues with different antioxidant (AO) status were studied before and after gamma-irradiation at the dose of 15 cGy (the dose rate were 0.01; 0.25 and 9 cGy/min); the X-ray exposure at the dose of 16 cGy (the dose rate was 44 cGy/min) and at the doses less 1.5 mGy under changing dose rate within action.
The spleen relative mass in groups of irradiated mice is mainly due to the total X-ray dose under changing dose rate, and the analogical index in the liver irradiated mice depends on the initial value of parameter for control. Experimental data demonstrated the different sensitivity of LPO parameters to the low intensity irradiation at the low doses depending on the dose rate and changing of these parameters being kept for a long time after action. The initial value of parameters is found to exert the more substantial influence on the spleen and liver relative mass, the phosphatidylcholine (PC) and lysoforms shares in the tissue phospholipids (PL) of mice. The content of TBA-reactive substances in the blood plasma is the most sensitivity parameter to the action of X-ray at low doses. The reliable changes and substantial influence of the dose rate, AO status of tissue and the duration after irradiation are revealed for the molar ratio of [sterols]/[PL], the PC/phosphatidylethanolamine ratio and the ratio of sums of more easily oxidizable to more poorly oxidizable fractions of PL. The X-ray changing dose rate primary effect on the formation of biological consequences is revealed at doses less than 0.5 mGy in the blood plasma and more than 0.5 mGy in brain.
The experimental data testify to the complicated nonlinear character of the biological effects under the action of ionizing radiation at low doses on mice. Besides, the biological effectiveness of irradiation under the different dose rate is substantial depended on the AO status of tissues and the duration after irradiation.
Primary author
Prof.
Lyudmila Shishkina
(no)
