Spatial memory and changes in expression of genes of neurotrophic factors in adult rat brain after fractionated whole brain irradiation
International Journal of Radiation Research
Ionizing radiaon causes cognive impairment in adult brain. However, the effects of various irradiaon protocols with fraconated fixed total dose on hippocampal funcon have not yet been studied. Materials and Methods: Fraconated whole brain irradiaon with a total dose of 36 Gy was performed according to the following protocols: 2Gy-18 fracons (2Gy*18), 4Gy-9 fracon (4Gy*9) and 6Gy-6 fracons (6Gy*6). Changes in spaal memory were studied in Morris water maze tests at 12 th and 17 th day a1er
... th day a1er irradiaon with a hidden pla2orm and at 38 th day a1er irradiaon without a pla2orm. Levels of expression of brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) genes were evaluated using qPCR. Results: Expression of genes of neurotrophic factors (BDNF and VEGF) was decreased at 4 th and 8 th week a1er irradiaon, the decrease depended on fraconaon. The Morris water maze test with a hidden pla2orm showed improvement in long-term spaal memory at 12 th a n d 1 7 th day a1er irradiaon. In the Morris water maze test without pla2orm cognive deficit was detected only in 6Gy*6 group at 4th week a1er irradiaon. Conclusion: Our study shows that different fraconaon protocols affect hippocampal funcons differently, and that the greatest negave impact has the protocol with the maximum single dose. In addion, decrease in expression of genes of neurotrophic factors might play an important role in cognive impairment.