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Objective:To explore the influence of dose-rate on radiation-induced gene expression in human peripheral blood.Methods:Human peripheral blood ex vivo was irradiated with 0, 1, 2, 4 and 6 Gy of 60Co γ-rays with different dose-rates of 0.2, 1 and 2 Gy/min. Human blood cells were harvested at 24 h post-irradiation. Following RNA isolation, the mRNA expression levels ofCDKN1A, MDM2, PCNA, FDXR, GADD45A, PHPT1, ASTN2, TNFSF4, POLH, GDF-15 and PPM1D were measured by quantitative real-time PCR. The stepwise regression method was used to establish the gene combination models. Results:The relative mRNA expression levels of 11 genes significantly increased in a dose-dependent manner within the dose range of 0-6 Gy with three dose-rates of irradiation ( R2=0.744-0.998, P< 0.05). Following the exposure to 2 Gy(0.2 Gy/min) 60Co γ-rays, the expression levels of CDKN1A, FDXR, PHPT1 and TNFSF4 genes were significantly higher than that of the 1 and 2 Gy/min groups ( t=3.73, 5.73, 2.44, 2.77, 3.53, 2.68, 2.43, 2.05, P< 0.05). With 6 Gy irradiation, the changes of radiation-induced PPM1D expression level under a dose rate of 2 Gy/min were significantly higher than other two dose-rates( t=3.82, 2.54, P< 0.05). The combined expression model at different dose rates was composed of 2-3 genes, and the R2values of regression equations were 0.976, 0.964 and 0.951, respectively. Conclusions:In a certain range, the dose-rate may affect the changes of radiation-induced gene expression in human peripheral blood.
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Objective:To explore the feasibility of the optimized cytokinesis-block (CB) assay on radiation-induced nucleoplasmic bridge (NPB), and to provide a scientific basis for the application of NPB in biological dose estimation.Methods:Human peripheral blood in vitro was irradiated with 2 Gy 60Co γ-rays at a dose rate of 1 Gy/min (0 Gy control group). According to the culture time after irradiation, blood samples were divided into group 48, 56, 68 and 72 h. Cytochalasin-B (Cyt-B) with a concentration of 6 μg/ml was added into the samples at 28 h and harvested at 48, 56, 68 and 72 h after irradiation, respectively. On the other hand, the blood samples were treated with different concentration of Cyt-B i. e., 0.6, 1, 2, 6 and 10 μg/ml at the beginning of culture (0 h) and harvested at 68 h after irradiation. The proportion of mononucleated, binucleated and multinucleated cells, radiation-induced NPB and micronucleus (MN) frequencies were analyzed. Results:The nuclear division index (NDI) and proportion of binucleated cells at 2 Gy and 0 Gy had tendency of increasing with cell culture time. NPB frequencies (0.023 0-0.033 0/cell) and MN frequencies had no significantly difference ( P> 0.05). With the increase of Cyt-B concentration, NDI and the proportion of binucleated cells in group 2 Gy and 0 Gy also increased, but NPB frequencies (0.023 0-0.047 0/cell) had no significant difference ( P> 0.05). MN frequencies of group 10 μg/ml were significantly lower than that of group 6 μg/ml ( U=2.74, P< 0.01). Conclusions:Cell culture time and Cyt-B concentration had no significant influence on radiation-induced NPB frequencies, suggesting that NPB could be obtained by appropriately reducing cell culture time and Cyt-B could be added into blood samples at the beginning of culture. But this protocol reduced the number of cells for further analysis, and thus its feasibility for dose estimation still need to be studied.
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Objective:To screen radiosensitive lipid metabolites in rat small intestine and analyze their metabolic pathways, in order to provide scientific basis for radiation enteropathy biomarkers.Methods:The total body irradiation of 60Co γ rays was performed to rats with different doses of 0, 1, 2, 3, 5 and 8 Gy. The changes of lipids in small intestine were studied by targeted lipidomics method based on liquid chromatography coupled mass spectrometry (LC-MS). Results:Fifteen lipids in small intestine were screened as radiosensitive metabolites at 3 d after irradiation, including 4 up-regulated lipids and 11 down-regulated lipids( t=-6.395, 5.998, 5.836, -5.503, -5.449, -5.422, 4.841, 4.802, 4.621, 4.457, 4.426, 4.373, 4.110, 3.945, 3.902, P< 0.05 and FDR < 0.05). The metabolic pathways of sphingolipid, glycerophosphoplipid were significantly enriched. Four phosphatidyl serines (PS)increased while 1 phosphatidic acid(PA), 2 sphingomyelins(SM) and 4 fatty acids(FA)decreased in a good dose-response manner( R2> 0.80, P< 0.05), which were more potential radiation enteropathy biomarkers. Conclusions:Lipid metabolites in rat small intestine were significantly changed after the rat was total body irradiated with 60Co γ-rays.Eleven lipids with good dose-response relationship were more potential to be radiation enteropathy biomarkers.
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Objective:To explore the effects of ultraviolet B (UVB) on the premature senescence of human immortalized keratinocytes HaCaT cells and the possible underlying molecular mechanism.Methods:HaCaT cells were exposed with UVB of different doses (20, 50, 80 and 100 mJ/cm 2). At 72 h after exposure, cellular morphology was observed by Giemsa staining, cell proliferation was detected by clone formation assay, and the proportion of premature senescence cells was detected by β-galactosidase staining. The number change of lysosomes was detected by Lyso-Tracker Red fluorescence probe at 24, 48 and 72 h after exposure. Cell migration was measured by scratch test at 24 h and 48 h after exposure. The protein expressions of p53 and p16 related to premature senescence were detected by Western blot assay at 72 h after exposure. Results:After UVB exposure, HaCaT cells showed a premature senescence phenotype. At 72 h after exposure, the cell volume increased ( F=115.18, P<0.05), the cell proliferation ability decreased ( F=410.32, P<0.05), the activity of β-galactosidase increased ( F=16.31, P<0.05), and the expressions of P53 and P16 increased. In addition, the number of lysosomes increased at 24, 48, and 72 h after exposure ( F=17.65, 38.36, 13.66, P<0.05), and cell migration capacity was inhibited at 24 and 48 h after exposure ( F=8.21, 11.48, P<0.05). Conclusions:UVB exposure can induce premature senescence of HaCaT cells by increasing the expression of p53 and p16 proteins.
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OBJECTIVE: To explore the dose-effect of X-ray irradiation and chromosome aberrations in human peripheral blood cells,and establish a dose-response curve of dicentric and ring(dic+r)aberration induced by X-ray irradiation.METHODS: Human peripheral blood samples were collected from three healthy individuals and were exposed to X-ray at the doses of 0.00,0.25,0.50,0.75,1.00,2.00,3.00,4.00 and 5.00 Gy in vitro.The dose rate was 1.158 Gy/min.The blood cells were harvested after routine culture,and the chromosome preparation was carried out.The dicentrics and rings in metaphase cells were counted under microscope,and a dose-response curve was fitted by using the software of CABAS.Dose estimation was performed according to the curve from two blind samples.RESULTS: Aberration of dic+r increased with irradiation doses in the range of 0.00-5.00 Gy(P<0.01).The dose-response relationship followed a linear-quadratic equation:■,where■ is the yield of dic+r,and D is the irradiated dose.The estimated doses of the two blind samples were in accordance with the actual doses.CONCLUSION: The dose-response curve and mathematical model of chromosome aberration following exposure to 0.00-5.00 Gy X-ray irradiation is established in this study provide a reliable method for the accurate dose estimation.
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Objective:To investigate the role of CD46 and Nectin-4 on Measles virus (MV) infecting human pulmonary alveolar epithelial cells (HPAEpiC),and the interaction between CD46 and Nectin-4.Methods: Measles virus was divided into pre-infection group and 2 h-infection group,HPAEpiCs treatment with anti-CD46 antibody and/or anti-Nectin-4 antibody as experimental groups,and untreated HPAEpiCs as a control.The variation of viral replication level was detected.A Co-immunoprecipitation assay (Co-IP) was used to explore whether CD46 and Nectin-4 had interactive relationship in MV infection.Results: Compared with the control group,MV titers were reduced in HPAEpiCs of the pre-infection group treated with anti-CD46 and anti-Nectin-4 respectively (48.03% and 49.53%).Furthermore,virus titers showed a more reduction in which treated with anti-CD46 and anti-Nectin-4 antibodies (27.15%,P<0.01).Western blot and Real-time PCR showed that anti-CD46 antibody and anti-Nectin-4 antibodies decreased the rate of MV infection.In the 2 h-infection group,however,the treatment with anti-CD46 and anti-Nectin-4 could significantly reduce the MV titer and NP protein in HPAEpiCs.The Co-IP assay showed that there were interaction between CD46 and Nectin-4.Conclusion: CD46 and Nectin-4 mediated MV infecting HPAEpiCs.Moreover,CD46 and Nectin-4 may play a synergetic role in MV infection,which could enhance the infection effect.
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Objective To explore the influences of the final concentration and adding time of Cytochalasin-B (Cyt-B) on radiation-induced nucleoplasmic bridges (NPB) in cytokinesis-block assay.Methods Hunan peripheral blood samples were divided into 5 final concentration groups (group 2,4,6,8,10 μg/ml) according to different final concentrations of Cyt-B.Moreover,blood samples were divided into 4 adding time groups (group 0,28,40,44 h) according to different adding times of Cyt-B.Blood samples were irradiated with 0 (sham irradiation) and 2 Gy 60Co-rays in vitro,at a dose rate of 1 Gy/min.A cytokinesis-block assay was carried out to prepare NPB samples.The percentages of mononucleated,binucleated and multinucleated cells,as well as the frequencies of NPB and micronucleus (MN) in binucleated cells were analyzed using an optical microscope.Results Nuclear division index (NDI) and the percentages of binucleated cells increased with increased concentration of Cyt-B,and decreased with delayed adding time of Cyt-B (except group 0 h) in both final concentration groups and adding time groups.After exposed to 2 Gy,NPB frequencies were no significant difference (except group 0 h).MN frequencies had the trend of decreased with the increased concentration of Cyt-B,but no significant difference with adding time of Cyt-B.Conclusions In cytokinesis-block assay,different final concentration and adding time of Cyt-B may induce to the variation of NPB frequencies,but there was no significant difference.Appropriate increased final concentration or ahead adding time of Cyt-B can increase the percentage of binucleated cells that help to improve the efficiency of analysis.
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In recent years, cytokinesis-block method was used to analyze cytomics indicators including micronucleus, nuclear bridge, nuclear bud, nuclear division index, cell apoptosis and cell necrosis. In public health, it has become the common method to explore the impacts of different population structure, environment and occupational exposure for genomic instability, chromosome breakage, chromosome loss and cell proliferation. This article reviews and discusses the application of using cytokinesis block method to analyze cytomics indicators in public health field.