Gross morphological changes of the mouse brain exposed prenatally to ionizing radiation

Gross morphological changes of the brains of first generation (F1) C57BL/6 x C3H hybrid male mice irradiated prenatally were studied at 6 months of age. Gravid female mice were irradiated with 1.0 Gy, 2.0 Gy or 3.0 Gy of gamma radiation on the 14th day of gestation. The brain in dorsal view was photographed. The measurements of the area and the distance of parts of the brain were made from photographs, using a computer system for biological image analysis. The body and brain weight and the area and length of the cerebral hemispheres (CHs) showed dose-related decrease. There was a dose related increase in the area of the superior colliculi (SC), the distance (DP) from the point which the medial walls of the CHs begin to slope away from the midline to the posterior end of CHs, and the proportion of the DP to the CH length. From the results of the dose-response curve, it appears that the area of the SC and the proportion of DP to CH length are affected by small doses of less than 1.0 Gy.