Abstract
Pregnant mice were irradiated by 200R of γ-ray of ^<60>Co on the 10th day of pregnancy and were administered continuously 1.0mg/day of vitamin E from the 1st day of pregnancy. Histological findings of the placenta of irradiated mice with vitamin E administration were investigated every two or three days in succession, comparing with those of control animals. In general, the irradiated placenta showed underdevelopment, degeneration and circulatory damage in its every layer and these changes were most manifest on the 4th day after irradiation. From the 6th day on these changes were gradually improved. These radiation injury of the placenta was reduced to some extent by the administration of vitamin E and its effect was noticed from the 2nd day after irradiation.
