Effects of occupational radiation exposure on peripheral blood lymphocyte count and cell cycle in logging workers / 中国辐射卫生

Objective To investigate the effects of prolonged low-dose neutron-γ radiation on peripheral blood lymphocytes of logging workers. Methods The health information of workers in a logging company was collected by on-site blood sample collection and questionnaire survey. Individual doses of γ and neutron radiation were recorded using LiF elements and CR-39, respectively. Lymphocyte count in peripheral blood was measured by blood cytometer. Cell cycle and cyclins were detected by flow cytometry. Results The annual dose of some logging workers exceeded 5 mSv. Lymphocyte counts showed a difference of 15% between the group exposed to the lowest annual dose of 0–1 mSv (mean: 2.45 × 109/L) and the group exposed to the highest annual dose of 5–25 mSv (mean: 2.08 × 109/L). In comparison to pre-shift workers, logging workers exhibited a G1-phase arrest in the lymphocyte cycle, along with increased expression of cyclins p21 and CDK2. Conclusion Prolonged exposure to low-dose neutron-γ radiation leads to reduced lymphocyte counts as well as changes in lymphocyte cycle and cyclin expression.

Preliminary study on dicentric chromosome identification algorithm based on artificial intelligence technology / 中华放射医学与防护杂志

Objective:To explore artificial intelligence technology and propose an algorithm for automatic identification of dicentric chromosomes to realize fast and high-throughput biodosimetry. In order to solve the time-consuming and laborious problem of manual analysis of dicentric chromosomes.Methods:Combining artificial intelligence technology and image processing technology, based on MATLAB software, algorithms like image preprocessing, threshold segmentation algorithm, binarization processing, area identification algorithm, convolutional neural network algorithm and double centripetal recognition algorithm were applied. A fuzzy membership function was defined to describe the degree of each chromosome belonging to a dicentric chromosome, and the discrimination threshold was set to realize the automatic identification of dicentric chromosomes.Results:Through the test on 1 471 chromosome images, compared with manual recognition, the detection rate of dicentric chromosomes cells of this algorithm reached 70.7%.Conclusions:This algorithm method carries out a preliminary study on the automatic identification of dicentric chromosomes with good result.

MiRNA expressions in peripheral blood plasma of workers in a certain mine / 中华放射医学与防护杂志

Objective:To investigate the effect of radon on the expressions of miR-16, miR-106b, miR-449a, let-7g, miR-21, miR-221 and miR-34a in peripheral blood plasma of miners.Methods:A total of 46 randomly selected miners worked underground(the underground group)and 38 miners worked aboveground (the control group). MiRNA levels in the underground and control groups were detected by qRT-PCR and their relationship with cumulative effective dose was further analyzed.Results:The levels of miR-106b, miR-21, miR-221 in plasma of the study group were significantly higher than those in the control group( Z=-2.32, -2.47, -2.79, P<0.05), the corresponding Fc values were 1.61, 1.75, 1.30, respectively. The levels of miR-16, miR-449a, let-7g and miR-34a were slightly higher than those in the control group ( P>0.05). After controlling of confounding factors such as age, BMI and smoking, the alteration of miR-16, miR-106b, let-7g, miR-21 and miR-221 in plasma of the underground group were positively correlated with the cumulative effective dose( t=2.50, 3.31, 2.60, 2.95, 3.25, P<0.05). No significant difference was observed in the plasma levels of miR-449a and miR-34a between the two groups ( P>0.05). Conclusions:miR-106b, miR-21 and miR-221 could be used as potential biomarkers of radon exposure.

Analysis of results of national biological dose estimation / 中华放射医学与防护杂志

Objective To analyze the biological dose estimation ability of the radiation health technology institutions nationwide from 2015 to 2017,and their development in recent years.Methods SPSS 19.0 software was used to analyze and pack the data involved in the 2015-2017 year assessments by using x2 test.Statistical analysis was conducted of qualification rate,excellent rate,participating units and dose estimation deviation distribution.Results The qualification rate gradually increased from 2015 to 2017.Compared with 2015,the passing rate significantly increased in 2017 with statistically significant difference(x2 =3.978,P ＜0.05).A total of 53 units participated in the biological dose assessment,of which 30 units were involved over the three consecutive years,accounting for 57％.In the distribution of the relative deviation of dose estimates made by the units participating in the three-year assessment,the proportion of estimated deviations in the range of 5％-10％ increased whereas those in the range of 15％-20％ and ＞ 20％ decreased.Conclusions During 2015-2017 year period the biological dose estimation ability of all units involved in the assessment nationwide was basically stable,with gradually improved test level,qualification rate and steady excellence rate.

Cell cycle and its regulatory proteins in the peripheral blood lymphocytes of the residents living in a radon hot spring area / 中华放射医学与防护杂志

Objective To observe potential effect of radon hot springs on the changes of cell cycle and its regulatory proteins of CDK1,CDK2,CDK4,CDK6,CyclinD1,CyclinE1,WEE1,CDC25A in the peripheral blood lymphocytes of residents.Methods A random sampling method was used to persons 46 persons from the residents around radon hot spring in Wentang town,and 39 persons were selected from the control area without radon exposure.Flow cytometry was used to detect the changes of cell cycle and the expressions of cell cycle-related regulatory proteins.Multiple linear regression method was used to analyze the relationship between the expressions of cell cycle regulatory proteins and radon exposure.Results The percentages of cells at G0/G1 phase and S phase in lymphocytes were different in the two groups (t =2.250,-2.382,P ＜ 0.05).The expression levels of CDK1,CDK6 and CyclinE1 in the peripheral blood lymphocytes of radon hot spring group were significantly decreased (t =4.770,11.419,5.238,P ＜ 0.05) and negatively correlated with radon exposure (t =-5.097,-11.128,-5.117,P ＜0.05).The expression levels of CDK2,CDK4,CyclinD1,WEE1 and CDC25A in the peripheral blood lymphocytes of radon hot spring group were increased but not significantly(P ＞ 0.05).Conclusions The incidences of a higher ratio of S-phase cells and lower expression levels of CDK1,CDK6 and CyclinE1 in the peripheral blood lymphocytes of residents in Wentang town may be related to long-term radon exposure.

MicroRNA expressions in peripheral blood plasma of the residents from high background radiation area of Yangjiang, China / 中华放射医学与防护杂志

Objective To explore the effects of high background radiation on the expressions of miR-16, miR-106b, miR-449a, miR-34a and let-7g in peripheral blood plasma of the residents .Methods Totally 110 healthy female long-term local residents aged over 50 years were randomly selected from the high background radiation area and the control area , while their age, body mass index(BMI) and other indicators were surveyed .The relative expression levels of miRNAs in peripheral blood plasma of these women were quantitatively detected by real-time fluorescence quantitative PCR ( RT-PCR) .Then t-test was used to analyze the cumulative dose , age and BMI between the high background and control group .Mann-Whitney U-test was used for statistical analysis of miRNA expression levels between two groups , and the multiple regression analysis was used finally .Results Compared with the control group , the cumulative dose of individuals in the high background group was about four times higher (t=42.803, P0.05).Conclusions miR-16 and miR-106b may serve as biomarkers for the early stage of low dose radiation health effects .

Effect of interference of SNCG gene on radiosensitivity of breast cancer T47D cells / 中华放射医学与防护杂志

Objective To explore the role of γ-synuclein(SNCG) siRNA in the radiosensitivity of breast cancer T47D cells.Methods SNCG siRNA was synthesized according to the coding sequence of SNCG mRNA and then transiently transferred into T 47D cell with lipofectamine .The expression of SNCG gene and protein was detected by RT-PCR and Western-blot, respectively.Cells were divided into three groups, SNCG siRNA interference group , negative control group and blank control group , which were irradiated with different doses of 60 Coγ-rays.Cell radiosensitivity was evaluated by colony formation assay , cell proliferation was assayed by CCK-8 kit, and the protein expressions of phosphorylated-AKT and mTOR were detected by Western blot assay .Results Compared with blank control cells , the expressions of SNCG gene and protein in the SNCG siRNA transferred T 47D cells were efficiently diminished .Cell colony formation results showed that , under 4, 6, 8 Gy irradiation, the cell survival of siRNA transfection group was lower than that of control group (t=5.449, 8.882, 21.503, P<0.05).CCK-8 experiments showed that the cell proliferation abilities of siRNA group at 24, 48, 72 h after 6 Gy irradiation were lower than those of control group (t=5.603, 4.839, 6.115, P<0.05).In addition, after 6 Gy irraddaition, the AKT and mTOR phosphorylation levels in the siRNA group were more obviously reduced compared with blank groups , but the total AKT and mTOR had no changes .Conclusions Transfection of SNCG siRNA can enhance the radiosensitivity of breast cancer cells probably by inhibiting p -AKT signal pathway .

Effects of exogenetic miR-34a on radiosensitivity of H1299 cells / 中华放射医学与防护杂志

Objective To investigate the influences of miR-34a on the radiosensitivity of H1299 cells.Methods CCK-8 kit was used to examine the viability of H1299 cells which were exposed to different doses (0,2,4,6 and 8 Gy) of 60Co γ-rays after transient transfection of pre-miR-34a.Apoptosis rate and cell cycle were measured with flow cytometry.The expression levels of miR-34a target genes,bcl-2,bax,CDK4,CDK6 and cyclinD1 were analyzed by real-time PCR.Results Compared to the control group of negative transfection,the cell viability in pre-miR-34a transfection group decreased significantly after irradiation at0,2,4,6,8 Gy (t=-2.39,-3.12,-4.98,-4.03,-3.06,P＜0.05) in a dose-dependent manner.After being irradiated with 6 Gy γ-rays,the apoptotic rate in pre-miR-34a transfection group was significantly increased (t =7.06,P ＜ 0.05) together with an accumulation of G0/G1 phase (t =3.94,P ＜ 0.05) and a reduction of S phase (t =6.23,P ＜ 0.05).The gene expression levels of bcl-2,CDK4 and CDK6 in pre-miR-34a transfection group were respectively decreased (t =3.39,12.88,6.21,P ＜ 0.05) of negative control.cyclinD1 was also decreased but no significance,while bax was increased to 1.94 times of negative control (t =-4.35,P ＜ 0.05) together with a decrease of bcl-2/bax.Conclusions miR-34a could promote cell apoptosis,induce G0/G1 phase accumulation,suppress cell activity,and in turn increase the radiosensitivity of H1299 cells.

Changes of lymphocytes and regulatory T cell subset of mice influenced by 60 Co γ-ray irradiation / 中华放射医学与防护杂志

Objective To analyze the influence of ionizing radiation on the lymphocytes and its regulatory T cells in mice.Methods Mice were administered with whole body irradiation of γ-rays at different doses,and lymphocytes were separated from thymus and spleen,then the number of total cells were counted and the percentages of CD4 + T and CD4 + FOXP3 + CD25 + Treg lymphocytes were analyzed by using FACS.Results The lymphocyte numbers in thymus and spleen decreased in dosedependent manner and reached to the minimum at 4 d after irradiation (F =118.08,144.01,P ＜ 0.05).Exposure to higher dose(more than 1 Gy) decreased Treg number time-dependently in thymus,however increased it in spleen.On the contrary,exposure to lower dose (less than 0.75 Gy) increased Treg number in thymus.Besides,the percentage of Treg cells increased dose-dependently(in thymus,F =5.16,89.44,3.01,P ＜ 0.05 ; in spleen,F =52.02,32.13,27.45,P ＜ 0.05).Conclusions The radiation responses of lymphocytes and their Treg subpopulation vary with the different doses.Treg cells are resistant to high dose irradiation,however,their differentiation could be induced by low dose irradiation.In addition,the different time-dependent responses of lymphocytes and their subpopulation to ionizing radiation indicate the difference of lymphocyte maturation,differentiation and emigration.

Micronucleated reticulocytes in the peripheral blood of mice exposed to 60Co γ-rays / 中华放射医学与防护杂志

Objective To detect the changes of the percentage of micronucleated reticulocytes (MN-RET) in the peripheral blood of mice exposed to 60Co γ-rays,in order to provide evidence for a new biomarker of radiation biodosimetry.Methods ICR mice were irradiated in whole body with 0,0.5,1,2,4 and 8 Gy at a dose rate of 0.24 Gy/min.Peripheral blood was collected for MN-RET assay using a flow cytometry.Results The percentage of peripheral MN-RET increased steadily with irradiation doses up to 2 Gy and then had a downtrend beyond 2 Gy.The changes of MN-RET observed with a microscope were consistent with the results from flow cytometry.The dose response of the MN-RET fitted to a lineal model (R2 =0.9063),and the MN-RET at 2 Gy was significantly higher than that of nonirradiated control (t =-2.856,P ＜ 0.05).Conclusion Percentage of peripheral M N-RET could be an early,rapid and high-throughput radiation bio-dosimeter in certain range of doses.

Expressions of lung cancer related genes and miRNA in peripheral blood of the residents surrounding hot springs with extremely high radon / 中华放射医学与防护杂志

Objective To investigate the expressions of lung cancer related genes and miRNA in peripheral blood of the residents surrounding the extremely high radon hot springs in Ruoergai County,Sichuan Province. Methods Peripheral blood samples were collected from the local residents.Expressions of lung cancer related genes (p53,k-ras) and miRNA (let-7a,miR-34a/b) were detected by real-time PCR and the protein expressions of p53 and k-ras were detected by Western blot.Results The expressions of p53 and k-ras mRNA of the residents in high radon area were 0.97 and 1.33 times of the control respectively (t =0.13,-1.12,P ＞0.05),and the p53 and k-ras protein levels were 0.70 and 1.23 times of the control respectively (t =0.72,0.46,P ＞ 0.05).The let-7a of the residents in high radon area was lower (t =1.63,P ＞ 0.05 ) while the miR-34a and miR-34b were significantly higher than those of the controls (t =- 3.20,- 3.32,P ＜ 0.05).Conclusions Based on the expressions of p53 and k-ras gene and miRNA,it can be concluded that the residents surrounding the high radon hot springs received radiation damage.

Effects of 60Co γ-ray partial radiation on chromosome aberration in human peripheral blood in vitro / 中华放射医学与防护杂志

Objective To investigate the effects of 60Co γ-ray partial radiation on chromosome aberration in human peripheral blood in vitro.Methods The samples of heparinized peripheral whole blood from 3 healthy persons were exposed to 60Co γ-rays at the doses between 0 and 8 Gy with the dose rate of 0.35 Gy/min at the temperature of 37 ℃ ,and then mixed with the unirradiated blood samples of the Microscopy was used to observe the chromosome aberration double ( centromere + centromere) and the biological dose was estimated thereby.ResultsThe amounts of double centromere + centromere were increased along with the dose of irradiation in all groups.The estimated biological dose was higher than the 1/3 of the irradiation dose when the dose was between 0.5 to 2 Gy,and was close to the 1/3 of the irradiation dose when the dose was between 4 to 8 Gy.Conclusion Chromosome aberration can be used as a biomarker in estimation of uneven irradiation.

Human lymphocyte damage and phosphorylation of H2AX and ATM induced by γ-rays / 中华放射医学与防护杂志

Objective To investigate 60Co γ-ray induced damage in lymphocytes and the relationship between doses of 60Co γ-ray irradiation and the levels of phosphorylated H2AX and ATM.Methods Cells were irradiated with 60Co γ-rays in the range of 0-8 Gy.The levels of phosphorylated H2AX and ATM were detected by Western blot and FACScan,respectively.The micronucleus(MN)was analyzed by CB method to evaluate DNA damage.Results FACScan results showed the dose-effect relationship of γ-H2AX expression were linear.square at 0.5 h post-irradiation to different doses,and the fitting curve was shown as Y=3.96+11.29D-0.45D2.The level of phosphorylated ATM(p-ATM)was not changed significantly by using the same method.Western blot showed that p-ATM protein expression was significandy increased after irradiation compared with sham.irradiated group.The MN assay which represented DNA damage was sensitive to different doses.Conclusions γ-ray irradiation could induce the phosphorylation of H2AX and ATM,which may play an important role in indicating DNA damage.Both of H2AX and ATM have the potential as sensitive biomarker and biodosimeter for radiation damage.

Effects of partial radiation in vitro on chromosome aberrations in human peripheral blood lymphocytes / 中华放射医学与防护杂志

Objective To analyze the chromosome aberrations induced by partial radiation in human peripheral blood lymphocytes in vitro.Methods Heparinized whole blood samples were exposed to 2 Gy ~(60)Co 7-rays at 37℃ ,and then mixed with non-irradiated blood by different ratio.The slides were prepared after culturing and the unstable aberrations were analyzed.Results The chromosome aberrations had a good relationship with the ratio of irradiated blood.The chromosome aberrations in partial irradiated group were higher than that in the irradiated group.The estimated dose was 1.27 Gy when the ratio was 1 : 1 ,greater than the dose of 1 Gy.The estimated dose was 0.93 Gy when the ratio was 0.5＝1,also greater than 0.5 Gy.But when the ratio was 1:0,the radiation dose was accordant with the estimated dose.Conclusions Chromosome aberrations could be a biomarker for estimating the uneven irradiation.

Effects of radon and its progeny on the expression and mutation of p53 in lung tissues of mice / 中华放射医学与防护杂志

Objective To explore the effect of radon and its progeny on the expression and mutations of p53 in lung tissue of mouse model. Methods Apoptosis was detected by terminal deoxynucleotidy transferase-mediated dUTP-biotin nick end labeling. The expression of p53 gene was analyzed by immunohistochemistry, Western blot and realtime-PCR. PCR-SSCP was used to detect the mutation of p53 in lung tissues. Results Compared with those in the control group, the apoptotic index were increased significantly in 30 WLM and 60 WLM groups( t = 18.11, -10.30,P ＜ 0.05 ). The p53 protein was increased significantly ( t = -11.08, P ＜ 0.05; t = - 7.00, P ＜ 0.0 ) ) in 30 WLM and 60 WLM groups. The mutation of p53 gene was not detected in lungs of radon-exposure mice. Conclusions Lung and bronchus might be the targets of radon and its progeny, and p53 gene plays an important role in the progression of radon-induced lung injury.

Experimental study on bystander effects K562 cells induced by ionizing radiation / 中华放射医学与防护杂志

Objective To study the bystander effects and associated mechanisms through irradiated conditioned medium(1CM). Methods Natural kilhr(NK) cells were obtained from peripheral blood samples. ICM irradiated with different doses of 60Coγ-rays was used for culturing K562 cell strain. The degree of injury of K562cells by activated NK cells was observed, as well as the apoptosis frequency of K562 cell was investigated. Results Severe injury was induced in K562 cells cultured in ICM than the control (sham-irradiated) as shown by increased sensitivity to NK cells (P < 0.05). The apoptosis frequency of K562 cell was increased significantly compared with the control cells (P < 0.05). Conclusions The bystander effect induced by irradiation is existent. ICM can trigger the bystander effect on K562 cell strains.

Radon induced pulmonary lesion and expression of P53 and Bcl-2,Bax in mice / 中华放射医学与防护杂志

Objective To establish the mice model of lung injury induced by radon,and to observe the changes of pulmonary lesion at different doses and to analyze the influence of radon exposure on P53 and Bcl-2、Bax expression in lung tissue.Methods Mice were exposed to radon of 30 and 60 WLM,respectively.Apoptosis was detected by terrainal deoxynucleotidy transferse-mediated dUTP-biotin nick end labeling(TUNEL).The expressions of P53,Bcl-2 and Bax protein were observed by immunohistochemistry and Western blot.Results Compared with those in the control group,the apoptotic indexes increased significantly in the 30 and 60 WLM groups(t=18.11,-10.30,P＜0.05).The protein expression of P53 was significantly increased(t=-11.08,P＜0.05).The expression levels of P53 and Bax were remarkably inereased(t=-7.00,-2.52,P＜0.05),while the expression of Bcl-2 protein was significantly decreased in the 60 WLM group(t=4.36,P＜0.05).But Bcl-2,Bax expression was decreased in both 30 WLM and 60 WLM groups(t=2.78,4.07,P＜0.05).Conclusions Radon could induce pulmonary lesion of mice.It may be involved in the regulation of apoptosis of pulmonary lesion by the P53,Bcl-2、Bax pathway.

Expression of JNK/SAPK in lung and bronchus of radon-exposed mice / 中华放射医学与防护杂志

Objective To study the expression of JNK/SAPK(c-Jun NH2-terminal kinase/stress activated protein kinase)in lung and bronchus of radon-exposed mice.Methods Male BALB/c mice were exposed to radon and its progeny with the cumulative dose of 0.02,30 or 60 working level month(WLM),respectively.The expression levels of JNK/SAPK in lung and bronchus were determined with Real-Time PCR,Western blot and immunohistochemistry methods.Results The JNK mRNA levels in lung tissues of mice exposed to radon of 30 and 60 WLM were higher than those of the control by 3.56 and 2.96 times,respectively.The relative expression levels of JNK and phospho-JNK proteins were higher than those of the control by using Western blot and immunohistochemistry methods.Condusiom Expose to the radon and its progeny might activate the JNK/SAPK intracellular signaling pathway.