Sex-Dependent Effects of 56Fe Irradiation on Contextual Fear Conditioning in C57BL/6J Mice

Effects of irradiation on hippocampal function have been mostly studied in male rodents and relatively little is known about potential effects of irradiation on hippocampal function in female rodents. Moreover, although the long-term effects of clinical radiation on cognitive function have been well established, the effects of other forms of irradiation, such as high charged, high energy radiation (HZE particles) that astronauts encounter during space missions have not been well characterized. in this study we compared the effects of 56 Fe irradiation on fear conditioning in C57BL/6J female and male mice. Hippocampus-dependent contextual fear conditioning was impaired in female mice but improved in male mice following 16 Fe irradiation. Such impairment was not seen for hippocampus-independent cued fear conditioning. Thus, the effects of 16 Fe irradiation on hippocampus-dependent contextual fear conditioning are critically modulated by sex. (C) 2009 Wiley-Liss, Inc.