Zoey Cheng1, Yu-Qing Li2, C Shun Wong3. 1. Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada. 2. Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. 3. Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Departments of Radiation Oncology and Medical Biophysics, University of Toronto, Toronto, Ontario, Canada. Electronic address: shun.wong@sunnybrook.ca.
Abstract
PURPOSE: To assess the influence of aging on hippocampal neuronal development after irradiation (IR). METHODS AND MATERIALS: Male mice, 2, 4, 6, 12, and 18 months of age, were given a single dose of 0 or 5 Gy of IR. A bromodeoxyuridine (BrdU) incorporation study was used to label newborn cells. Neural progenitors, newborn neurons, and microglia in dentate gyrus (DG) were identified by phenotypic markers, and their numbers were quantified by nonbiased stereology 9 weeks after IR. RESULTS: BrdU-positive or newborn cells in DG decreased with aging and after IR. The number of neuroblasts and newborn neurons decreased with aging, and a further significant reduction was observed after IR. Total type 1 cells (the putative neural stem cells), and newborn type 1 cells decreased with aging, and further reduction in total type 1 cells was observed after IR. Aging-associated activation of microglia in hippocampus was enhanced after IR. CONCLUSIONS: The aging-associated decline in hippocampal neurogenesis was further inhibited after IR. Ablation of neural progenitors and activation of microglia may contribute to the inhibition of neuronal development after IR across all ages.
PURPOSE: To assess the influence of aging on hippocampal neuronal development after irradiation (IR). METHODS AND MATERIALS: Male mice, 2, 4, 6, 12, and 18 months of age, were given a single dose of 0 or 5 Gy of IR. A bromodeoxyuridine (BrdU) incorporation study was used to label newborn cells. Neural progenitors, newborn neurons, and microglia in dentate gyrus (DG) were identified by phenotypic markers, and their numbers were quantified by nonbiased stereology 9 weeks after IR. RESULTS:BrdU-positive or newborn cells in DG decreased with aging and after IR. The number of neuroblasts and newborn neurons decreased with aging, and a further significant reduction was observed after IR. Total type 1 cells (the putative neural stem cells), and newborn type 1 cells decreased with aging, and further reduction in total type 1 cells was observed after IR. Aging-associated activation of microglia in hippocampus was enhanced after IR. CONCLUSIONS: The aging-associated decline in hippocampal neurogenesis was further inhibited after IR. Ablation of neural progenitors and activation of microglia may contribute to the inhibition of neuronal development after IR across all ages.
Authors: Olga Zając-Spychała; Mikołaj A Pawlak; Katarzyna Karmelita-Katulska; Jakub Pilarczyk; Katarzyna Derwich; Jacek Wachowiak Journal: Neuroradiology Date: 2017-01-10 Impact factor: 2.804