Effects of long-term low-dose γ-rays exposure on radiosensitivity of human B lymphoblast cells / 中华放射医学与防护杂志
Chinese Journal of Radiological Medicine and Protection
;
(12): 256-260, 2013.
Article
in Chinese
| WPRIM
| ID: wpr-434874
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.
Full text:
Available
Index:
WPRIM (Western Pacific)
Language:
Chinese
Journal:
Chinese Journal of Radiological Medicine and Protection
Year:
2013
Type:
Article
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