| Zhang Yaping,Zhang Xuxia,Wang Jing,Bao Yizhong,Li Jiaying,Yin Lina,Chen Honghong.Repair of alpha-particle-induced DNA double strand breaks and their localization in chromatin in human lymphocytes[J].Chinese Journal of Radiological Medicine and Protection,2014,34(5):329-333 |
| Repair of alpha-particle-induced DNA double strand breaks and their localization in chromatin in human lymphocytes |
| Received:October 14, 2013 |
| DOI：10.3760/cma.j.issn.0254-5098.2014.05.003 |
| KeyWords:α-particle irradiation DNA double-strand break (DSB) repair foci Chromatin Human lymphocytes |
| FundProject:国家自然科学基金（81273000） |
| Author Name | Affiliation | E-mail | | Zhang Yaping | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Zhang Xuxia | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Wang Jing | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Bao Yizhong | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Li Jiaying | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Yin Lina | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | Chen Honghong | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | hhchen@shmu.edu.cn |
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| Abstract:: |
| 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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