title: Early effects of whole-body (56)Fe irradiation on hippocampal function in C57BL/6J mice.
abstract: Relatively little is known about early irradiation effects on hippocampal function in wild-type mice. In this study, the effects of (56)Fe irradiation on hippocampal function were assessed starting 2 weeks after whole-body irradiation. Compared to sham irradiation, radiation impaired novel object recognition in female and male C57BL/6J wild-type mice. There were no effects of irradiation on contextual fear conditioning or spatial memory retention in the water maze. It is possible that oxidative damage might contribute to radiation-induced cognitive changes. Therefore, hippocampal and cortical levels of 3-nitrotyrosine (3NT) and lipid peroxidation, measures of oxidative damage were assessed. There were no effects of irradiation on these measures of oxidative damage. As (56)Fe irradiation can increase reactive oxygen species (ROS) levels, which may contribute to the impairments in novel object recognition, the effects of the antioxidant alpha-lipoic acid (ALA) on cognition following sham irradiation and irradiation were also assessed. ALA did not prevent radiation-induced impairments in novel object recognition and impaired spatial memory retention of sham-irradiated and irradiated mice in the probe trial after the first day of hidden platform training in the water maze. Thus, the novel object recognition test is particularly sensitive to detect early cognitive effects of (56)Fe irradiation through a mechanism unlikely involving ROS or oxidative damage.
authors.affiliation: Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, Oregon 97239, USA.
authors.forename: Gwendolen E
authors.initials: GE
authors.lastname: Haley
authors.forename: Lauren
authors.initials: L
authors.lastname: Yeiser
authors.forename: Reid H J
authors.initials: RH
authors.lastname: Olsen
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Davis
authors.forename: Lance A
authors.initials: LA
authors.lastname: Johnson
authors.forename: Jacob
authors.initials: J
authors.lastname: Raber
mesh_terms: D000818:Animals; D003071:Cognition / Q000528:radiation effects; D003213:Conditioning, Psychological / Q000528:radiation effects; D005239:Fear / Q000523:psychology / Q000528:radiation effects; D005260:Female; D006624:Hippocampus / Q000378:metabolism / Q000502:physiology* / Q000528:radiation effects*; D007501:Iron / Q000009:adverse effects*; D015227:Lipid Peroxidation / Q000528:radiation effects; D008297:Male; D018782:Maze Learning / Q000528:radiation effects; D051379:Mice; D008810:Mice, Inbred C57BL; D017382:Reactive Oxygen Species / Q000378:metabolism; D021641:Recognition, Psychology / Q000528:radiation effects; D013997:Time Factors; D014916:Whole-Body Irradiation / Q000009:adverse effects*
chemical_list: D017382:Reactive Oxygen Species; D007501:Iron