Radiation-induced developmental abnormalities of the brain ventricles in the golden hamster.

The dysontogenesis of the brain ventricle system of golden hamster fetuses was studied after X-ray irradiation of the mother at different stages of pregnancy. Groups of gravid hamsters were irradiated with a single dose (200 R) on either the 6th, 8th, 10th or 12th day of gestation. The fetuses were removed 1 day before birth. The most prominent finding in all stages of development was the dilatation of the brain ventricles. In addition to hydrocephalus, hematocephaly was also found in some cases. Furthermore, a widening of the central canal of the spinal cord with hemorrhagic content could sometimes be observed. Ependymal ectopies and subependymal rosettes occurred more frequently when irradiation was given in the late fetal period. The experimental findings demonstrate that after irradiation of the mother animal, malformation of the brain may be produced during the whole intrauterine period of development. The pattern and extent of malformation depend not only upon the dose of irradiation but also upon the stage of development at which irradiation was given.