The Effects of Chronic Ingestion of Tritiated Water on Prenatal Brain Development

Abstract

In view of the anticipated increased use of atomic energy in industry, the possible long-term effects of chronic radiation exposure were studied in five generations of rats. Female rats (F/sub 0/) were given tritiated drinking water (/sup 3/HOH;3..mu..Ci/ml) from adolescence (60 days) until and throughout pregnancy. A separate study showed that the maximum radioactivity in the urine is reached in 30 days, and in the blood in 42 days. In the newborns, the highest specific activity was in the nucleic acid fraction, but total radioactivity was mainly due to the water (body fluids) compartment. No signs of radiation illness or increase in cataract formation in the mothers were observed. The food and water intake and body weight changes before pregnancy were normal. The course and the outcome of pregnancy were also normal. However, 60% of the newborns (F/sub 1/) exhibited hematomas, edemas, and subdural hemorrhages, which disappeared at 30 days of age. Bollod analysis of the F/sub 1/ offspring at various ages did not reveal significant differences from the controls, except for a significant decrease in alkaline phosphatase. Newborn body weight and cerebral weight were also normal. On the other hand, cerebral DNA, protein, and protein/DNA were significantly lower. /supmore » 3/HOH administration was then continued throughout weaning, adolescence, and next pregnancies, to give F/sub 3/, F/sub 4/, and F/sub 5/ generations. The newborns in F/sub 3/--F/sub 5/ showed no more cerebral damage than those in F/sub 1/, i.e., there was no cumulative effect of radiation; presumably the maximum radioactivity level was already attained in F/sub 1/. As the generations progressed, the radiation damage to the developing brain became less pronounced; a possibility of inducible DNA repair has been discussed.« less