Abstract: Ionizing radiation has become an inevitable health concern emanating from natural sources like space travel and from artificial sources like medical therapies. In general, exposure to ionizing radiation such as γ-rays is one of the methods currently used to stress specific model systems. In this study, we elucidated the long-term effect of acute and fractionated irradiation on DCX-positive cells in hippocampal neurogenesis. Groups of two-month-old C57BL/6 female mice were exposed to whole-body irradiation at acute dose (5 Gy) or fractional doses (1 Gy × 5 times and 0.5 Gy × 10 times). Six months after exposure to γ-irradiation, the hippocampus was analyzed. Doublecortin (DCX) immunohistochemistry was used to measure changes of neurogenesis in the subgranular zone (SGZ) of the hippocampal dentate gyrus (DG). The number of DCX-positive cells was significantly decreased in all acute and fractionally irradiation groups. The long-term changes in DCX-positive cells triggered by radiation exposure showed a very different pattern to the short-term changes which tended to return to the control level in previous studies. Furthermore, the number of DCX-positive cells was relatively lower in the acute irradiation group than the fractional irradiation groups (approximately 3.6-fold), suggesting the biological change on hippocampal neurogenesis was more susceptible to being damaged by acute than fractional irradiation. These results suggest that the exposure to γ-irradiation as a long-term effect can trigger biological responses resulting in the inhibition of hippocampal neurogenesis.
Keywords: neurogenesis; ionizing radiation; immunohistochemistry; doublecortin; long-term effects
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Park, M.-K.; Kim, S.; Jung, U.; Kim, I.; Kim, J.K.; Roh, C. Effect of Acute and Fractionated Irradiation on Hippocampal Neurogenesis. Molecules 2012, 17, 9462-9468.
Park M-K, Kim S, Jung U, Kim I, Kim JK, Roh C. Effect of Acute and Fractionated Irradiation on Hippocampal Neurogenesis. Molecules. 2012; 17(8):9462-9468.
Park, Min-Kyoung; Kim, Seolhwa; Jung, Uhee; Kim, Insub; Kim, Jin Kyu; Roh, Changhyun. 2012. "Effect of Acute and Fractionated Irradiation on Hippocampal Neurogenesis." Molecules 17, no. 8: 9462-9468.