Zuzanna Setkowicz-Janeczko podpisana: Zuzanna Setkowicz

Female Wistar rats were exposed to a single 1.0 Cy dose of gamma radiation on gestational days 13, 15, 17 or 19 (E13, E15, E17 and E19, respectively). Their 8- and 16-day old male offsprings were injected with H-3-thymidine and sacrificed 4 h after the injection. Brain sections were immunostained for S100 beta protein and subjected to autoradiography. Thereafter, the dorsal parr of the hippocampal formation was examined microscopically and numbers and locations of proliferating astrocytes were recorded. Following prenatal irradiation, the intensity of astrocyte proliferation was considerably reduced, especially in the region of dentate gyrus. The reduction showed regular trend of changes being much stronger in brains irradiated on E19 than in those irradiated on E13. The changes, therefore, were related to the stage of brain development at which the irradiation was performed. A possible role of neuronal regulatory influence on the postnatal development of glial cells was discussed.