| DONG Xiao-rong,Ruebe Claudia,Ruebe Christian,WU Gang.Ionizing radiation-induced DNA double-strand break and repair assessed by γ-H2AX foci analysis in neurons in mice[J].Chinese Journal of Radiological Medicine and Protection,2009,29(1):5-8 |
| Ionizing radiation-induced DNA double-strand break and repair assessed by γ-H2AX foci analysis in neurons in mice |
| Received:June 28, 2008 |
| DOI：10.3760/cma.j.issn.0254-5098.2009.01.002 |
| KeyWords:γ-H2AX DNA double-strand breaks Radiosensitivity |
| FundProject:国家自然科学基金资助项目(30800283) |
| Author Name | Affiliation | E-mail | | DONG Xiao-rong | Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China | | | Ruebe Claudia | Department of Radiation Oncology, Saarland University Hospital, Germany | | | Ruebe Christian | Department of Radiation Oncology, Saarland University Hospital, Germany | | | WU Gang | Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China | wugangzr@yahoo.com.cn |
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| Abstract:: |
| Objective To investigate if the γ-H2AX foci is a precise index for the DSB formation and repair in mature neurons of brain in vivo after clinically relevant doses irradiation.Methods For the DSB formation experiment, the mature neurons in the neocortex of brain tissue of C57BL/6 mice were analyzed at 10 min after whole-body irradiation with 0.1, 0.5 and 1.0 Gy. For the DSB repair kinetics experiment, the mature neurons in the neocortex of brain tissue of repair-proficient (C57BL/6 mice) and repair-deficient mouse strains (BALB/c, A-T and SCID mice) were analyzed at 0.5, 2.5, 5, 24 and 48 h after whole-body irradiation with 2 Gy. The mature neurons in the neocortex of brain tissue of sham-irradiated mice of each strain served as controls. γ-H2AX immunohistochemistry and γ-H2AX and NeuN double immunofluorescence analysis was used to measure DSBs formation and repair in the mature neurons in the neocortex of brain tissue of the different mouse strains. Results For the DSB formation experiment, γ-H2AX foci levels with a clear linear dose correlation and very low backgrounds in the nuclei in the neocortex of brain tissue were observed. Scoring the loss of γ-H2AX foci allowed us to verify the different, genetically determined DSB repair deficiencies, including the minor impairment of BALB/c mice. Repair-proficient C57BL/6 mice exhibited the fastest decrease in foci number with time, and displayed low levels of residual damage at 24 h and 48 h post-irradiation. In contrast, SCID mice showed highly increased γ-H2AX foci levels at all repair times (0.5 h to 48 h) while A-T mice exhibited a lesser defect which was most significant at later repair times (≥5 h). Radiosensitive BALB/c mice exhibited slightly elevated foci numbers compared with C57BL/6 mice at 5 h and 24 h but not at 48 h post-irradiation.Conclusion Quantifying the γ-H2AX foci in normal tissue represents a sensitive tool for the detection of induction and repair of radiation-induced DSBs at clinically relevant doses in vivo. |
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