Prenatal Irradiation and Spatial Memory in Mice: Investigation of Dose-response Relationship

Abstract

Pregnant CD1 mice were exposed on gestational day 18 to 250 kV X-rays at 0·1, 0·25, 0·35 and 0·5 Gy. The performances of 10 adult male offspring from each exposure condition were investigated on a spatial discrimination learning task in a radial arm maze. An impairment in the performance of this task was found which showed a correlation with dose. Compared with sham exposed control mice, performance was not significantly affected with irradiation at 0·1 Gy and was slightly but non-significantly reduced at 0·25 Gy. Irradiation at 0·35 Gy caused a significant impairment in performance, and exposure at 0·5 Gy resulted in a still larger impairment. The overall association between dose and behavioural impairment was best described by a linear relationship without a threshold, although at doses lower than about 0·25 Gy any impairment would appear to be too small to be detectable.