Development of a small-animal focal brain irradiation model to study radiation injury and radiation-injury modifiers.

AbstractPurpose: Our aim was to establish an effective small-animal focal brain radiation model for research on brain injuries.Material and methods: Groups of up to six rats were exposed to a range of doses from 120–40 Gy, at 10 intervals of a 6 MeV electron beam. Open-field motor functions and water maze learning-memory tests were performed after the irradiation at two-week intervals. Morphological changes were detected through repeated magnetic resonance imaging (MRI) monthly and were compared with the histopathological findings to determine if they predicted late microscopic changes.Results: The development of necrosis proved to be dose-dependent. 120 Gy resulted in serious deterioration within 4 weeks in all rats. Localized necrosis in one hemisphere was detected 2 months after the irradiation with ≥ 70 Gy, and 3 months after 40–60 Gy consistent for all animals. The Morris water maze (MWM) tests proved to be the most sensitive tool for the early detection of a brain functional impairment. MRI screenin...