Irradiation neurotoxicity assessed in organotypic cultures of rat hippocampus

The neurotoxic effects of irradiation on the developing nervous system were studied in organotypic cultures of hippocampus prepared from newborn Sprague-Dawley rats. Hippocampus slices of 7-day-old rats were irradiated at the day of explantation at doses of 1, 2 and 4 Gy, and cultured in a roller drum for a fortnight. Light and electron microscopy showed remarkable damage to neuronal cells following irradiation, oligodendrocytes and myelogenesis being also affected. In contrast to alterations in neuronal perikarya, no morphological changes in synapses were obvious, though their number seemed to be reduced after irradiation with 4 Gy. These results confirm that low dose radiation produces damage to the central nervous system not only pre-natally, but even in post-natal periods of differentiation and development.