Radiation research
-
Little is known about the direct biological effects of radiation on immature neurons, despite its relevance to the mental retardation caused by irradiation of the brains of fetuses and children. In this study, we investigated the effects of radiation using primary cultured hippocampal neuronal cells with exclusion of glial cells, focusing on cell survival and structural development. Primary neurons were prepared from the hippocampi of fetal rats at embryonic day 18 and cultured according to Banker's methods. ⋯ The number of TUNEL-positive neurons, which can be considered as undergoing apoptosis, increased significantly in a dose-dependent fashion at both 7 and 14 days after irradiation. The mean numbers of clusters of synaptic proteins on neural dendrites, which are considered to represent their developmental level, decreased dose-dependently at both 7 and 14 days after irradiation. These results suggest that radiation not only induces apoptosis but also produces structural defects in the surviving neurons that may directly suppress neural development.