Does A Single Low Dose of Ionizing Radiation Induce Alzheimer\u27s Disease-Like Alterations in Mice?

BackgroundA recent study in mice reported early transcriptional response in brain to low-dose X-rays (0.1Gy) suggesting alterations of molecular networks and pathways associated with cognitive functions, advanced aging and Alzheimer\u27s disease (AD). As humans are increasingly exposed to ionizing radiation from various sources including medical diagnosis and space, the possible cognitive and behavioral consequences induced by low-dose ionizing radiation are of great concern. The aim of the present study is to investigate the acute transcriptional responses as well as the late cognitive and behavioral consequences induced by ionizing radiation at low doses.MethodsC57BL/6J mice were whole-body irradiated with either X-rays (0.1Gy) or accelerated carbon ions (0.05 Gy or 0.1 Gy). The expression of AD-related genes in the hippocampus was analyzed by RT-PCR-array. The learning ability and memory were measured by Morris Water Maze test. Accumulation of fibrillary amyloid beta peptide (Abeta) was detected by amyloid imaging with positron emission tomography (PET). Characteristic AD pathologies including expression of amyloid precursor protein (APP), Abeta, tau and phosphorylated tau were examined with immunohistochemical staining.ResultsAt 4 hours after radiation significant transcriptional alterations in several AD-related genes were observed but no marked changes were found 1 year later. No significant difference on learning ability and memory was observed 1 and 2 years after irradiation. No detectable accumulation of fibrillar amyloid and the expression of APP, Abeta, tau, phosphorylated tau in the brains of the animals 4 months and 2 years after radiation.ConclusionsIn mice, a single low dose of ionizing radiation induced significantly acute transcriptional alterations in several AD-related genes while no marked late consequences on behavior al and AD-related pathological changes in brains were observed.AAIC>12:Alzheimer\u27s Association International Conferenc