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SIM-A9 is a line of spontaneously immortalized mouse microglial cells obtained from the brain of newborn C57BL/6 mice. The purpose of this work is to characterize the microglia of the SIM-A9 mouse line on the basis of the ratio of cells with the phenotype of resting and activated microglia in culture and to analyze the expression of markers of CD133 stem (progenitor) cells and nestin, which are receptors for growth factors CSF-1R and EGFR, as well as to analyze the karyotype of this line. Light microscopy and immunocytochemistry combined with flow cytometry and RT–PCR were used to analyze the morphology, phenotype, and expression level of pro-inflammatory cytokine genes, and the mFISH method was used to analyze the karyotype. It has been shown for the first time that SIM-A9 cells express a high level of TSPO protein and CD68, CD11b, and CD45high markers on the surface membrane of cells, which corresponds to the phenotype of activated microglia. Despite this, the cells of the line respond with additional activation in response to lipopolysaccharide stimulation, which leads to an increase in the expression of pro-inflammatory cytokine genes IL-1β, TNFα, and IL-6 and the formation of a high level of active oxygen and nitrogen metabolites. SIM-A9 cells were shown to express markers of stem and progenitor cells CD133+ and nestin, which allows us to consider them as early poorly differentiated progenitor cells, despite their phenotype corresponding to activated microglia. It was also found that SIM-A9 cells express receptors of the two growth factors CSF-1 and EGF, CSF-1R and EGFR, which indicates the possibility of stimulation of SIM-A9 cell proliferation by two alternative mechanisms under the action of corresponding factors. SIM-A9 cells have a hypotetraploid karyotype with a large number of structural and quantitative chromosome anomalies. [ABSTRACT FROM AUTHOR]

We studied the effects of whole body gamma-radiation (4 Gy, dose rate 0.6 Gy/min) and proton-beam head irradiation (with an energy of 150 meV, 4 Gy and a dose rate of 0.8 Gy/min) on the intensity and timing of audiogenic seizures in rats of the Krushinsky–Molodkina selected strain. In experiments using gamma rays the rat behavior was tested in the open field, elevated plus maze, and Morris water maze tests. No changes in audiogenic tonic–clonic seizures (originating in the brain stem) were found during the first exposure to sound after gamma-irradiation. Slower development of seizures and larger latency of the tonic seizure phase were found following serial daily exposure to sound in rats after proton irradiation. It was also noted that audiogenic myoclonic seizures (which developed in the forebrain) in irradiated rats that were exposed daily to sound had shorter durations, while the intensity of these seizures was at a maximum in all groups. The behavioral tests revealed a moderate increase in anxiety after radiation exposure. [ABSTRACT FROM AUTHOR]

The mutagenic effect of accelerated heavy charged particles on the Chinese hamster V79 cell line is studied. The induction of HPRT mutations in irradiated cells for a long expression time (up to 45 days) after exposure to radiation with different LET are analyzed. The maximum yield of mutant clones is observed at different expression times, depending on the characteristics of ionizing radiation; in this case, the position of the maximum is shifted toward later time intervals with increasing LET of radiation. [ABSTRACT FROM AUTHOR]

Proton-beam irradiation (1, 2, and 4 Gy, 150 MeV) of hybrid male mice F1 (CBA × C57BL/6J) has changed their adaptive behavior in a different ways. The irradiated mice performed significantly less successfully than control ones in the puzzle-box test at those stages when the underpass to the safe box compartment was masked by wood shavings, and they had to dig to get to it. At the same time, they were significantly more successful at the stages when the underpass was masked by a light plug, which should be removed as it blocked the entrance. A reduction in neurogenesis in two proliferative forebrain zones had been demonstrated in irradiated mice. [ABSTRACT FROM AUTHOR]