Permature death of Purkinje cells following low-level X-ray irradiation during embryonic development.

Rat embryos were exposed to 170 r of X-ray irradiation on day 15 or 18 of gestation, and sacrificed when they reached the postnatal age of 30 days. In the cerebella of these animals, normal-looking and atrophied Purkinje cells were studied and compared with those observed in the cerebellum of the normal animals. The normal animals did not show presence of any atrophied Purkinje cells, but the X-ray-irradiated animals showed a lesser number of Purkinje cells and many atrophied Purkinje cells. In the cerebellum of animals that were X-ray-irradiated on day 15 of gestation, the number of Purkinje cells was only 32% of those in the normal cerebellum, and in those that received X-ray irradiation on day 18 of embryogenesis there were about 95.5% as many Prukinje cells as in the normal cerebellum. But, in the cerebella of animals in the latter group there were two to three times more atrophied Purkinje cells than in the cerebella of animals in the former group. These findings are discussed in terms of lasting effects of low-level X-ray irradiation in the form of premature atrophy and death of the Purkinje cells.