Analyzis of Exploratory Rearing and Microglia Level after γ-Irradiationof Mice at Sublethal Doses
The effect of sublethal doses of total γ-irradiation on murine locomotor activity and exploratory rearing and on the number of resting and activated microglia in the brain was studied in the dynamics after exposure. According to the data of an automatic analysis of the parameters characterizing the locomotor activity of animals in dynamics after irradiation at doses of 1, 2 and 4 Gy, no significant differences were found in the Open Field test. Differences were established only by the number of rearings, which was reduced after 2 weeks and 1 month after irradiation, but did not differ from the control after 2 and 3 months. The content of leukocytes in the blood below 50% of the normal level in the period between 7–14 days after exposure allowed the prediction of exploratory rearing impairment in the late period - one month after irradiation. A dose-dependent decrease in the number of microglial cells in the first week after irradiation and their increase one month after exposure was found. An increase in the number of activated microglia cells occurred only in the 1st day after irradiation. The findings suggest that there are no signs of neuroinflammation in the long-term period after total exposure of mice at doses of 1, 2 and 4 Gy. The observed decrease in the exploratory behavior of mice after total exposure at sublethal doses may be due to inhibition of neurogenesis in the hippocampus and neurotransmission disturbances or damage of the neurons structure.