| YE Shuang,YUAN De-xiao,XIE Yue-xia,PAN Yan,SHAO Chun-lin.Effects of long-term low-dose γ-rays exposure on radiosensitivity of human B lymphoblast cells[J].Chinese Journal of Radiological Medicine and Protection,2013,33(3):256-260 |
| Effects of long-term low-dose γ-rays exposure on radiosensitivity of human B lymphoblast cells |
| Received:January 10, 2013 |
| DOI：10.3760/cma.j.issn.0254-5098.2013.03.010 |
| KeyWords:Low-dose-radiation Cell proliferation Radiosensitivity Apoptosis Gene expressions |
| FundProject:国家自然科学基金(81273001,11179002,31070758) |
| Author Name | Affiliation | E-mail | | YE Shuang | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | YUAN De-xiao | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | XIE Yue-xia | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | PAN Yan | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | | | SHAO Chun-lin | Department of Radiation Biology, Institute of Radiation Medicine, Fudan University, Shanghai 200032, China | clshao@shmu.edu.cn |
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| Abstract:: |
| Objective To investigate the effects of long-term low-dose radiation (LDR) of γ-rays on the proliferation and radiosensitivity of human lymphoblast cells HMy2.CIR (HMy) and to elucidate the underlying mechanism.Methods HMy cells were divided into control group and long-term LDR group. For the long-term LDR treatment, HMy cells were fractionally exposed to a low dose of γ-rays, which could enhance cell proliferation, 3 times per week for 4 weeks. After the long-term LDR exposure, part of the control and long-term LDR exposed cells were further irradiated with a challenging dose (2 Gy) of γ-rays. Then cell proliferation and radiosensitivity were assayed by CCK-8 kit, cell apoptosis, and γ-H2AX formation was measured by flow cytometry. Gene expressions of cyclinD1, PCNA, bcl-2 and bax were detected by RT-PCR. Results The long-term LDR significantly increased cell proliferation (t=9.607,P<0.01) accompanied with up-regulation of cell cycle regulation gene cyclinD1 (t=6.869, P<0.01), proliferation regulation gene PCNA (proliferating cell nuclear antigen) (t=9.229, P<0.01) and bcl-2 gene (t=2.662,P<0.05), but decreased the expression of pro-apoptotic gene bax (t=19.908, P<0.01) in HMy cells. Compared to untreated cells, the long-term LDR decreased cell radiosensitivity (t=8.896,P<0.01), including apoptosis induction (t=4.762,P<0.01) and γ-H2AX formation (t=10.264, P<0.01). Conclusions The long-term LDR promoted cell proliferation by up-regulating cell cycle related genes, while it reduced the radiosensitivity of HMy cells with acquisition of apoptotic resistance. |
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