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.

Objective:To improve the ability of radiation health technical institutions for biological dose estimation.Methods:A total of 144 institutions nationwide, including the CDC, prevention and treatment center for occupational disease, colleges and universities, scientific research institutes, nuclear industry systems, and medical and physical examination institutions, were organized to carry out the intercomparison of national biological dose estimation capabilities in 2022. The institutions participating in the comparison were divided into two types of A and B, through the identification of chromosome aberrations, to estimate the irradiation dose (A) or chromosome aberration rate (B). The results were summarized and compared, and the main problems were analyzed and discussed.Results:There were 60 institutions in type A, 52 qualified institutions (including 12 excellent institutions) and 8 unqualified institutions, with a pass rate of 86.7% (20.0% excellent) and a failure rate of 13.3%. There were 84 institutions participating in the biological dose estimation comparison of type B, with 48 qualified institutions, and 36 unqualified institutions, the qualified rate was 57.1%, and the unqualified rate was 42.9%.Conclusions:Most of the institutions participating in type A comparison have the ability to estimate biological dose, and more than half of the institutions participating in type B comparison have the ability to analyze chromosome aberration. The overall ability of institutions participating in type A comparison is higher than in type B.

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.

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.

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.

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 .

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, P<0.05), and the levels of miR-16 and miR-106b in plasma of high background group were down-regulated, while the level of miR-449a was up-regulated ( Z =4.180, 2.422, 2.794, P <0.05 ).After controlling of confounding factors such as age and BMI , the expression levels of miR-16 and miR-106b were negatively correlated with the cumulative dose of individuals (P<0.05).On the contrary, no significant correlation was observed between the levels of miR-449a, miR-34a, let-7g and the individual cumulative dose (P>0.05).Conclusions miR-16 and miR-106b may serve as biomarkers for the early stage of low dose radiation health effects .

Objective To investigate the expressions of miR-210-3p,miR-221-3p,miR-21-5p and miR-150-Sp in the plasma of breast cancer patients before and after radiotherapy in order to establish reliable early biomarkers of non-uniform radiation injuries.Methods Blood samples were collected from 13 patients before radiotherapy (0 Gy) and 24 h after radiotherapy of 2,10,20,30 Gy.The miRNAs in the blood plasma were detected with qRT-PCR.Results The levels of miR-210-3p,miR-221-3p,miR-21-5p had no significant difference among different dosage groups after radiotherapy(P ＞ 0.05).There was no significant difference between the expression of miR-150-5p before and after 2 Gy radiotherapy (P ＞ 0.05).While the relative level of miR-150-5p gradually decreased to 0.808,0.605,0.565 (x2 =18.76,P ＜ 0.05) with increased accumulative dosage of 10,20,and 30 Gy,respectively.In addition,the miR-150-5p expression levels had no relationship (P ＞ 0.05) with situations (positive or negative group) of human epidermal growth factor receptor 2 (HER2),estrogen receptor (ER) and progesterone receptor (PR) in the breast cancer cells.Conclusions Ionizing radiation could reduce the expression of miR-150 in the plasma of breast cancer patients in a dose-dependent manner.

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.

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.