Unresolved microgliosis and impaired neurogenesis are associated with cognitive deficiency in a clinically relevant mouse model of fractionated whole brain radiation

The objective of this study is to evaluate the cellular and molecular changes associated with the cognitive function as a late- effect of clinically relevant fractionated whole brain irradiation (fWBI) treatment using immunocompetent mouse model. Microglia are not only the immune mediators of the brain but also involved in synaptic pruning and neurogenesis. However, the microglial response to fractionated radiation and how this contributes to radiation-induced cognitive impairment is poorly understood. Here, C57BL/6J mice were randomized into two groups. One group received X-radiation (XRT) and another was sham treated (CTL). The whole brain of each XRT mouse received a total of 30 Gy (3 Gy/fraction) of radiation over two weeks. XRT and CTL mice were then evaluated for cognitive and behavioral functions after one, four, and six months of radiation treatment using the rotarod test, novel object recognition test, the free running Y-Maze and Barnes Maze. Whole brains were harvested and stored after completion of behavioral studies for immunohistochemical analysis. Microglia were enriched by Percoll gradient separation and extracted mRNA was characterized by qPCR analysis. A significant (P Citation Format: Suman Kanji, Benjamin Johnson, Kristina Witcher, Pooja Gulati, John Gregory Bodnar, Julie Fitzgerald, Courtney DeVries, Randy Nelson, Jonathan Godbout, Saikh Jaharul Haque, Saikh Jaharul Haque, Arnab Chakravarti. Unresolved microgliosis and impaired neurogenesis are associated with cognitive deficiency in a clinically relevant mouse model of fractionated whole brain radiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr LB-326.