Effects of prenatal x-irradiation on motor performance in the rat

¹ Animal Behavior Laboratory, Lafayette Clinic, and Department of Radiology, Wayne State University, Detroit, Michigan

Gravid albino rats of the Sprague-Dawley strain received either 25, 50, or 100 r whole-body X-radiation on either day 5, 10, 15, or 20 of gestation. Controls were sham-irradiated. Over 500 surviving offspring were evaluated on measures of motor maturation of the upright and righting responses, motor strength, and locomotor learning during the neonatal period. The results indicate that radiation exposure of 100 r on day 15 of gestation retards motor maturation of the upright and righting responses. Almost all of the radiation groups show a decrease in motor strength as compared to the control group with maximum deficits in the groups receiving 50 or 100 r on day 10 or 15 of gestation. On the locomotor learning measure, the results are not consistent, but the group receiving 100 r on day 15 of gestation is maximally affected. These deficits in motor performance are related to observable motor impairment. It is concluded that low levels of radiation received prenatally can have detrimental effects on the development of motor performances in the rat.