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Objective To analyze the micronucleus levels of peripheral blood lymphocytes of medical radiation workers, and to provide a basis for radiation protection to reduce occupational hazards caused by ionizing radiation. Methods A total of 1072 medical radiation workers were selected into radiation group, and 329 healthy adults who underwent pre-employment occupational physical examination and intended to be radiation workers were selected into control group. The micronucleated lymphocyte frequency was determined by whole blood micro-culture. Results There were no significant differences in micronucleated cell frequency and micronucleus frequency between the radiation group and the control group (both P > 0.05). The detection rate of micronucleus abnormalities in the radiation group was significantly higher than that in the control group (P < 0.001). Female radiation workers had significantly higher micronucleated cell frequency, micronucleus frequency, and the detection rate of micronucleus abnormalities than male radiation workers (all P < 0.001). Between different types of work, significant differences were observed in micronucleated cell frequency and micronucleus frequency (both P < 0.05), but not in the detection rate of micronucleus abnormalities (P > 0.05). Radiation workers with different lengths of working showed significant differences in micronucleated cell frequency (P < 0.05), micronucleus frequency (P < 0.05), and the detection rate of micronucleus abnormalities (P < 0.001). Significant differences were observed in micronucleated cell frequency and micronucleus frequency between different age groups (both P < 0.05). The Spearman’s rank correlation analysis showed that micronucleated cell frequency and micronucleus frequency were positively correlated with the age of radiation workers (both P < 0.001). Conclusion The micronucleus frequency of radiation workers was related to the type and length of work, and had a positive correlation with age. Radiation protection should be enhanced for workers engaged in medical radiation for a long period, especially female workers and workers with a long length of service.
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OBJECTIVE: To compare the effects of ~(56)Fe~(17+),~(12)C~(6+)ion beams and~(60)Co γ rays on chromosome aberration in human lymphoblastoid cells. METHODS: The human lymphoblastoid cells were divided into 0. 1,0. 3,0. 5,0. 7,1. 0,2. 0 Gy irradiated groups and 0. 0 Gy control group. They were separately exposed to ~(56)Fe~(17+)ion beams( linear energy transfer was 400. 0 ke V/μm),~(12)C~(6+)ion beams( linear energy transfer was 26. 0 ke V/μm) and~(60)C γ rays. Chromosome specimens were harvested 48 hours after irradiation. The effects of different radiation on dicentric plus centric ring( “d + r”) aberration rate and chromosome aberration in human lymphoblastoid cells were detected by light microscope with artificial counting. RESULTS: The “d + r”aberration rates induced by 0. 3-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)Co γ rays at the same dose( P < 0. 017). Chromosome aberration cell rates of 0. 1-2. 0 Gy ~(12)C~(6+)ion beams were significantly higher than those of ~(56)Fe~(17+)ion beams and~(60)C γ rays at the same dose( P < 0. 017). At the dose range of 0. 0-2. 0 Gy,chromosome aberration effects of three kinds of radiations were gradually increased( P < 0. 01). The relative biological effectiveness of ~(56)Fe~(17+)ion beams was lower than that of ~(12)C~(6+)ion beams.CONCLUSION: The chromosome aberration induced by ~(12)C~(6+)ion beams was more serious than that of~(60)Co γ rays and ~(56)Fe~(17+)ion beams.
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Objective To investigate the effect of CDT1 gene over-expression on the apoptosis and cell cycle distribution in liver cells with a characteristic of genomic instability induced by radiation(GIR).Methods Lentivirus particles were transferred into liver cells of GIR to up-regulate the expression of CDT1 gene.The apoptosis and the cell cycle were detected by flow cytometry (FCM).The expression changes of p53,ATM,ATR,Bcl-2,and Caspase-3 genes were analyzed by real-time fluorescence quantitative PCR.Results CDT1 gene was efficiently increased by the gene transfection(t =15.56,P ＜ 0.05).In the CDT1 over-expressed cells,while the apoptosis ratio was increased (t =4.19,P ＜ 0.05),the expressions of p53 and Bcl-2 gene were decreased (t =-4.21,-2.06,P ＜ 0.05),but the expression of ATM,ATR and Caspase-3 changed with no significant difference compared with control.Conclusions Over-expression of CDT1 could regulate genomic instability through apoptosis pathway and checkpoint independent of p53.
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Objective To explore the effects of HAVCR2 siRNA on apoptosis and cell cycle in the radiation-caused genomic instable liver cells.Methods RNAi was used to inhibit HAVCR2 gene transcription.Cellular apoptosis and cell cycle distribution were detected by flow cytometry (FCM).Expression of p53 gene was assayed by real time fluorescence quantitative PCR.Results HAVCR2 gene was effectively inhibited by RNAi (t =19.21,P ＜ 0.05).After siRNA transferring,cell apoptosis (t =3.65,P ＜ 0.05) and p53 gene expression (t =4.82,P ＜ 0.05) were decreased,and G2-phase arrest was induced(t =-3.41,P ＜ 0.05).Conclusion HAVCR2 siRNA can decrease the generation of apoptosis in the genomic instable liver cells and blocks the cells at G2 phase.