Radiation-induced apoptosis in the neonatal and adult rat spinal cord

作     者：Li, YQ Wong, CS 

作者机构：Univ Toronto Univ Hlth Network Princess Margaret Hosp Dept Radiat Oncol Toronto ON M5G 2M9 Canada Univ Toronto Div Expt Therapeut Toronto ON M5G 2M9 Canada 

出 版 物：《RADIATION RESEARCH》 (辐射研究)

年 卷 期：2000年第154卷第3期

页      面：268-276页

核心收录：

学科分类：0710[理学-生物学] 070207[理学-光学] 07[理学] 08[工学] 0803[工学-光学工程] 1009[医学-特种医学] 0702[理学-物理学] 

主　　题：年龄因素 动物 新生 细胞凋亡/辐射效应 细胞分裂/辐射效应 因子Ⅷ/分析 神经胶质原纤维酸性蛋白质/分析 原位杂交 原位缺口末端标记 神经组织蛋白质类/分析 神经胶质/病理学 神经胶质/辐射效应 神经元/病理学 神经元/辐射效应 辐射损伤 实验性/病理学 辐射耐受性 大鼠 近交F344 脊髓/生长和发育 脊髓/病理学 动物 女(雌)性 大鼠 

摘      要：This study was designed to characterize radiation-induced apoptosis in the spinal cord of the neonatal and young adult rat. Spinal cords (C2-T2) of 1-, 2 and 10-week-old rats were irradiated with a single dose of 8, 18 or 22 Gy, Apoptosis was assessed histologically according to its specific morphological features or by using the TUNEL assay. Cell proliferation was assessed immunohistochemically using BrdU, Identities of cell types undergoing apoptosis were assessed using immunohistochemistry or in situ hybridization using markers for neurons, glial progenitor cells, microglia, oligodendrocytes and astrocytes, The time course of radiation-induced apoptosis in 1- or 2-week-old rat spinal cord was similar to that in the young adult rat spinal cord. A peak response was observed at about 8 h after irradiation, and the apoptosis index returned to the levels in nonirradiated spinal cords at 24 h, The neonatal rat spinal cord demonstrated increased apoptosis compared to the adult, Values for total yield of apoptosis over 24 h induced by 8 Gy in the neonatal rat spinal cord were significantly greater than that in the adult. Immunohistochemistry studies using Leu7, galactocerebroside, Rip and adenomatous polyposis coli tumor suppressor protein indicated that most apoptotic cells were cells of the oligodendroglial lineage regardless of the age of the animal. No evidence of Gfap or factor VIII-related antigen positive apoptotic cells was observed, and there was a small number of apoptotic microglial cells (lectin-Rca1 positive) in the neonatal and adult rat spinal cord. In the neonatal but not adult rat spinal cord, about 10% of the apoptotic cells appeared to be neurons and were immunoreactive for synaptophysin, Labeling indices (LI) for BrdU in nonirradiated 1- and 2-week-old rat spinal cord were 20.0 and 16.3%, respectively, significantly greater than the LI of 1.0% in the 10-week-old rat spinal cord. At 8 h after a single dose of 8 Gy, 13.4% of the apoptotic cells were Brd