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Quantitative detection of γ-radiation-induced DNA double-strand breaks using γ-H2AX foci in mouse organs, lymphocytes and scid lymphoma cell line

使用 γ-H2AX 灶定量检测小鼠器官、淋巴细胞和 scid 淋巴瘤细胞系中 γ 辐射诱导的 DNA 双链断裂

基本信息

批准号：
15510051
负责人：
NAKAJIMA Hiroo
金额：
$ 2.43万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

Several biological markers, mutation, chromosome aberration, microneuclei, colony formation, etc. have been used to measure radiation doses. However, enormous numbers of animals or cells are required to measure such low frequent events induced by radiations. To measure the radiation damage more precisely and sensitively, it is better to detect the first or earliest events in cells after irradiation (DNA double-strand breaks), especially in repair deficient cells or animals. Mice (C.B17 strain) and scid lymphoma cells (from C.B17-scid mice) were exposed to ^<137>Csγ-rays (0.1, 0.2, 0.5, 1, 2 and 4 Gy). Quantitation of DNA double-strand breaks in scid lymphoma cells, C.B17 peripheral lymphocytes, and organs was carried out by measuring signal intensity or counting fluorescence signal number of γ-H2AX foci in cells. The γ-H2AX foci appeared within 3 min after irradiation and reached a maximum fluorescence in 60 min. In lymphocytes, lymphoma cells, and cells from the mouse organs (brain, liver, kidney, testis), the relationships between the numbers of γ-H2AX foci and radiation dose was found to be linear over the entire dose range studied. These results suggest that quantitation of DNA double-strand breaks by the γ-H2AX foci is an useful biodosimeter for detecting high and low dose radiation damage in mice. Intriguingly, in the villi cells from the small intestine, no increase of γ-H2AX foci was found after irradiation. Genes related to the γ-H2AX phosphorylation are supposed to express in all cells of organs to repair spontaneous DNA double-strand breaks caused environmental effects, e.g. radiation and chemicals, however, it seems that theses essential systems are not working in all organs.

若干生物标记、突变、染色体畸变、微核、菌落形成等已被用于测量辐射剂量。然而，需要大量的动物或细胞来测量这种由辐射引起的低频率事件。为了更精确和灵敏地测量辐射损伤，最好检测辐射后细胞中的第一个或最早的事件（DNA双链断裂），特别是在修复缺陷的细胞或动物中。将小鼠（C.B17品系）和scid淋巴瘤细胞（来自C.B17-scid小鼠）暴露于15 <137>Csγ射线（0.1、0.2、0.5、1、2和4戈伊）。通过测量细胞中γ-H2 AX灶的信号强度或计数荧光信号数量来定量scid淋巴瘤细胞、C.B17外周淋巴细胞和器官中的DNA双链断裂。γ-H2 AX灶在照射后3 min内出现，60 min达到最大荧光强度。在淋巴细胞、淋巴瘤细胞和小鼠器官（脑、肝、肾、睾丸）细胞中，γ-H2 AX灶的数量与辐射剂量在整个剂量范围内呈线性关系。结果表明，γ-H_2AX灶对DNA双链断裂的定量检测是一种有效的生物剂量计，可用于检测高、低剂量辐射损伤。有趣的是，在小肠绒毛细胞中，照射后未发现γ-H2 AX灶的增加。与γ-H2 AX磷酸化相关的基因被认为在器官的所有细胞中表达，以修复由环境效应（例如辐射和化学物质）引起的自发性DNA双链断裂，然而，似乎这些必要的系统并不在所有器官中工作。