Effects of long-term low-dose γ-rays exposure on radiosensitivity of human B lymphoblast cells
10.3760/cma.j.issn.0254-5098.2013.03.010
- VernacularTitle:长期低剂量γ照射对人B淋巴母细胞辐射敏感性的影响
- Author:
Shuang YE
;
Dexiao YUAN
;
Yuexia XIE
;
Yan PAN
;
Chunlin SHAO
- Publication Type:Journal Article
- Keywords:
Low-dose-radiation;
Cell proliferation;
Radiosensitivity;
Apoptosis;
Gene expressions
- From:
Chinese Journal of Radiological Medicine and Protection
2013;(3):256-260
- CountryChina
- Language:Chinese
-
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.
