| 张亚平,张旭霞,王晶,暴一众,李佳颖,殷丽娜,陈红红.α粒子照射诱发DNA双链断裂修复及其在染色质中的分布[J].中华放射医学与防护杂志,2014,34(5):329-333 |
| α粒子照射诱发DNA双链断裂修复及其在染色质中的分布 |
| Repair of alpha-particle-induced DNA double strand breaks and their localization in chromatin in human lymphocytes |
| 投稿时间：2013-10-14 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.05.003 |
| 中文关键词: α粒子 DNA双链断裂修复 染色质 人外周血淋巴细胞 |
| 英文关键词:α-particle irradiation DNA double-strand break (DSB) repair foci Chromatin Human lymphocytes |
| 基金项目:国家自然科学基金（81273000） |
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| 中文摘要: |
| 目的 探索α粒子照射诱发人外周血淋巴细胞双链断裂（DSB）的修复特点及与染色质结构的关系，为其作为α核素内照射鉴定指标和生物剂量估算指标提供实验依据。方法 取4名健康成人外周血淋巴细胞，0.5Gyα粒子和γ射线照射，采用免疫荧光技术检测照射后10min~48hDSB分子标志物γH2AX焦点、同源重组（HR）修复蛋白Rad51焦点的形成及其消除过程，以及它们在染色质中的分布。结果 与未照射时相比，人淋巴细胞经0.5Gyα粒子照射后10min~2h，可见明显的线性γH2AX焦点径迹形成（t=11.12、14.40、16.56，P<0.05），至照后6h基本消失；而γH2AX焦点形成数在α粒子照射后30min达到最大值（t=51.72，P<0.05），6h内快速下降（t=29.83，P<0.05），至照后24~48h残留焦点数约为16%；照后10min，约27%的γH2AX焦点位于DAPI亮染的异染色质区，可能降低了其修复效率。而0.5Gyγ射线照射后10min~48h，未见线性γH2AX焦点径迹形成，随机、散在分布的γH2AX焦点均位于DAPI淡染的常染色质区，焦点形成数与残留数均显著低于α粒子照射诱发的焦点数。修复蛋白Rad51焦点在α粒子和γ射线照射后30min~2h有升高趋势，但与本底值无明显差异，且与γH2AX焦点的共定位仅占3%~8%。结论 α粒子照射诱发人外周血淋巴细胞线性γH2AX焦点径迹形成可作为判断是否存在α粒子内照射的生物指标，其在照射后稳定存在一定时间的特性，为其作为生物剂量估算指标提供了可能。 |
| 英文摘要: |
| Objective To investigate the characteristics of repair of DNA double strand breaks(DSB) induced by high-LET α-particle irradiation and their relationship with chromatin structure in the G0 lymphocytes of human peripheral blood, in order to provide the experimental basis for the judgement and dose evaluation of internal α-particle radiation.Methods Peripheral whole blood were collected from four healthy adults and lymphocytes were separated.A monocellular layer of human lymphocytes attached in Mylar film were irradiated with 0 and 0.5 Gy of α-particles and the lymphocytes suspensions were irradiated with 0 and 0.5 Gy of γ-rays.The formations of γH2AX foci as a surrogate marker of DSB and Rad51 foci as a marker of homologous recombination (HR) repair and their spatial localization in chromatin structure were measured by immunofluorescence staining technique at 10 min-48 h post-irradiation.Results Linear γH2AX foci tracks were observe at 10 min-2 h post-irradiation in lymphocytes exposed to α-particle irradiation(t=11.12, 14.40, 16.56, P<0.05), and almost completely disppeared at 6 h post-irradiation.The frequencies of γH2AX foci peaked at 30 min after α-particle irradiation (t=51.72, P<0.05) and then decreased rapidly during 6 h post-irradiation (t=29.83,P<0.05).The average number of foci remained only about 16% at 24-48 h post-irradiation.Moreover, 27% of γH2AX foci located at DAPI-bright heterochromatin region at 10 min after α-particle radiation, suggesting that the efficacy of DSB repair may be decreased.In contrast, at 10 min-48 h after γ-ray irradiation, no linear γH2AX foci track was observed and the γH2AX foci diffused randomly in nucleus and predominantly located in DAPI-weak euchromatin region.The numbers of formative and residual γH2AX foci after γ-ray irradiation were significantly less than those after α-particle radiation.During 30 min-2 h after α-particle and γ-ray irradiation, the frequencies of Rad51 foci slightly but not significantly increased in comparison with background level, and the frequencies of co-localization of Rad51 foci and γH2AX foci were only 3%-8%.Conclusions The formation of linear γH2AX foci tracks induced by high-LET α-particle irradiation in G0 human lymphocyte could be used as biological indicator to estimate whether a person has been exposed to internal α-particle radiation.Prolonged persistence of residual γH2AX foci may be applicable for biological dosimetry. |
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