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Objective@#To study the effects of sex, age, length of service, type of work and annual effective radiation dose on nucleoplasmic bridge (NPB) in the peripheral blood lymphocytes of radiation workers.@*Methods@#The peripheral blood samples of 100 radiation workers in Henan province were collected and the NPB in peripheral blood lymphocytes were measured by CBMN assay. The frequencies of NPB formation and NPB-containing cells were calculated, and the effects of various factors on NPB incidence were analyzed statistically.@*Results@#The NPB frequency in radiation workers was higher than that in healthy people (Z=-8.123, P<0.01). Except for sex, the factors of age, length of service, type of work and annual effective dose had significant influences on NPB (χ2= 7.202-45.571, P<0.05).@*Conclusions@#NPB reflects the effect of low-dose long-term chronic irradiation on the occupational radiation workers.
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Objective To study the effects of sex,age,length of service,type of work and annual effective radiation dose on nucleoplasmic bridge (NPB) in the peripheral blood lymphocytes of radiation workers.Methods The peripheral blood samples of 100 radiation workers in Henan province were collected and the NPB in peripheral blood lymphocytes were measured by CBMN assay.The frequencies of NPB formation and NPB-containing cells were calculated,and the effects of various factors on NPB incidence were analyzed statistically.Results The NPB frequency in radiation workers was higher than that in healthy people (Z=-8.123,P＜0.01).Except for sex,the factors of age,length of service,type of work and annual effective dose had significant influences on NPB (x2=7.202-45.571,P＜0.05).Conclusions NPB reflects the effect of low-dose long-term chronic irradiation on the occupational radiation workers.
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Objective To investigate a potential radiation biodosimetry based on multiple gene expressions.Methods Human peripheral blood were exposed to 60Co γ-rays at doses from 0 to 8 Gy.The mRNA expression levels of 10 selected genes were detected 6 and 12 h after irradiation by RT-PCR.Individual variation was also examined.An optimal mathematical model of the dose response of these gene expression levels at each time point was obtained by the stepwise regression method.A blind test was conducted to validate the statistical accuracy of dose estimation.Results The 10 selected genes expression levels at each time point were significantly increased along with dose from 0.5 to 8 Gy (R2 =0.61-0.97,P ＜ 0.05).Individual variations were evident in the gene expressions of TNFSF4,PHPT1 and FDXR.The gene expression levels of PCNA,CCNG1,TNFSF4,PHPT1,GADD45A and FDXR were incorporated into the model at 6 h after exposure (R2 =0.88,F =54.8,P ＜ 0.001);the gene expression levels of PCNA,CCNG1,TNFSF4,MDM2,GDF15 and TNFRSF10B were included in the model at 12 h after irradiation (R2 =0.82,F =42.767,P ＜ 0.001).These two statistical models can be utilized for the dose estimation accurately.Conclusions The multiple gene expressions have a potential as a radiation biodosimetry.
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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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Objective To explore whether a low dose of 60Co γ-rays could induce the adaptive response in the formation of nucleoplasmic bridges (NPB) in human peripheral blood lymphocytes,and if so,the range of the priming dose.Methods Human peripheral blood samples from healthy males were collected and irradiated with 0,20,50,75,100,150 and 200 mGy (dose-rate was 25 mGy/min) of 60Co γ-rays.After 6 h,the samples were irradiated with a challenge dose of 2 Gy (dose-rate was 1 Gy/min).The cytokinesis-block micronucleus (CBMN) assay was carried out to analyze the NPB and micronuclei (MN) formation in binucleated cells.Results Within the dose range of 0-200 mGy,the yields of NPB and MN increased with irradiation dose of γ-rays and the dose response of NPB followed with a linearquadratic equation of y =(1.5 × 10-4) x2-(5.67 × 10-3)x + 0.598 (R2 =0.893 8).Compared with the samples irradiated with 2 Gy alone,the yields of NPB and MN were significantly reduced when the samples were irradiated with a priming dose of 75-100 mGy before 2 Gy irradiation (U =2.66,2.97,3.96,5.89,P ＜0.05).The biggest decrease ratio of NPB yields approached to 43.2％ at the priming dose of 100 mGy.Conclusions Low doses in the range of 75-100 mGy of 60Co γ-rays could induce the adaptive response of NPB formation in human peripheral blood lymphocytes.
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Objective To investigate the dose response of S100A4 gene expression in the irradiated lymphoblastoid cells AHH-1 at different time points post irradiation.Methods AHH-1 cells was exposed to different doses(0,1,3,5,8,10,15 and 18 Gy)of 60Co γ-rays,and its mRNA levels of S100A4 was detected by reverse transcription PCR and real-time PCR at 4,8,12,24,48 and 72 h after irradiation.Results Within the range of applied doses,the level of S100A4 gene expression was upregulated with a good dose-response (R2 =0.79-0.93,P ＜ 0.05) and had obvious difference at different time points (F =8.91,P ＜ 0.01).Conclusion S100A4 gene expression at transcriptional level could be detected easily and had optimum dose-responses at certain time points after irradiation,and hence is applicable as a dosimeter.
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Objective To investigate the effect of radiation on the mitochondrion in adenocarcinoma A549 cells.Methods After A549 cells were irradiated with 0,0.5,3 or 8 Gy of 60Co γrays,mitochondrion membrane potential of A549 cells was detected by JC-1 probe,and ATP activity was measured by ATP kit in a chemiluminescence apparatus.The mitochondria DNA copy numbers was detected by real-time PCR assay.Results At 24 h after radiation,the mitochondrion membrane potential of A549 cells in all the irradiated groups changed significantly (F =243.44,P ＜ 0.05),among which 0.5 or 3 Gy of radiation resulted in a significant increase of mitochondrion membrane potential of A549 cells (t =-10.12,-5.59,P ＜ 0.05).However,the mitochondrion membrane potential of A549 cells exposed to 8 Gy of radiation decreased significantly 24 h after radiation (t =15.22,P ＜ 0.05).The mitochondrion membrane potential of A549 cells in all radiation groups returned to the normal level 48 h after radiation (F =10.36,P ＜ 0.05).24 h after radiation,the level of ATP in A549 cells significantly changed respectively(F =97.08,P ＜ 0.05),similar to the mitochondrion membrane potential.The ATP level in 0.5 and 3 Gy groups increased significantly (t =1.66,7.27,P ＜ 0.05),and the level of ATP in 8 Gy group decreased significantly (t =-8.24,P ＜ 0.05).Furthermore,48 h after both 0.5 and 3 Gy of radiation,the ATP content in A549 cells was still higher than that in untreated A549 cells (t =4.60,8.53,P ＜0.05).The mitochondria DNA copy numbers in A549 cells increased significantly in all the radiation groups (F =118.00,P ＜ 0.05).Compared with untreated A549 cells the mitochondria DNA copy numbers in A549 cells increased at 0.5 Gy by 12 times(t =0.02,P ＜0.05),and increased at 3 and 8 Gy by 7 and 10 times,respectively (t =9.68,15.10,P ＜ 0.05).Conclusions High dose of radiation resulted in the decrease of mitochondrion membrane potential of A549 cells,which subsequently affected the production of ATP.However,radiation with moderate and lower dose could lead to the compensatory increase of mitochondrion membrane potential of A549 cells,which promoted the production of ATP.The mitochondria DNA copy numbers compensatory would increase after A549 cells were exposed to radiation within 8 Gy.
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Objective For developing safe and effective anti-radiation new drugs,the effects of different lipoic acid amino acid salts on radiosensitivity were investigated.Methods The free radical scavenging ability of the above salts was evaluated in Fenton system.CCK-8 assay and flow cytometry assay were performed to evaluate the survival rate of L02 and apoptosis of AHH-1 after γ-ray irradiation,respectively.Results The lipoic acid arginine salt had the best ability of scavenging free radicals in Fenton system with an IC50 of 8.40 μ moL/ml.The survival assay showed that lipoic acid amino acid salts had better stability and equal ability in radioprotection (P ＞ 0.05) compared with lipoic acid.The apoptosis assay indicated that all lipoic acid amino acid salts could inhibit radiation-induced apoptosis,where lipoic acid arginine salt was more effective (t =-6.67,P ＜ 0.01).Conclusions Lipoic acid arginine salt has good radioprotection effect on L02 and AHH-1 cells by scavenging free radicals.
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Objective To investigate the dose-effect relationship of mRNA level of sensitive mitochondrial genes in human lymphoblastoid cells induced by ionizing radiation.Methods Seven human sensitive genes,including ND3,Cyt b,COX Ⅰ,COX Ⅱ,COX Ⅲ,ATPase6 and ATPase8 were chosen.Changes of mRNA level of these genes were detected by RT-PCR and Real-Time PCR at 24 h after irradiation in human lymphoblastoid cells,which were exposed to 0 - 15 Gy of 60 Co γ-rays.Results The expression of these 7 genes at mRNA level was up-regulated 24 h after irradiation in human lymphoblastoid cells.The level of gene expression of COX Ⅰ,which belongs to complex Ⅳ of mitochondrial respiratory chain,was most obvious,and the peak occurred after irradiation of 8 Gy,which was 13 times of the control group.A good dose-effect relationship was showed for COX Ⅲ gene expression at dose range of 3 -10 Gy as well as 3 - 15 Gy for other 3 genes including ND3,ATPase6 and ATPase8.Conclusions Gene expression levels of COX Ⅲ,ND3,ATPase6 and ATPase8 24h post-irradiation at certain irradiation dose range could be used for radiation damage biomarkers.
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Objective To explore the changes of human mitochondrial COX Ⅰ , COX Ⅱ and COX Ⅲ genes expression induced by ionizing irradiation. Methods Changes of human COX genes expression were detected by RT-PCR and Real-time PCR 8 h after the irradiation in human lymphoblastoid cell lines,which were exposed to 1-10 Gy60Co γ-rays. The protein levels were detected by flow cytometry and the COX activity was measured by colorimetry. The dose-effect relationships between the expression changes of the genes and the doses were established. The changes of these genes expression were also analyzed at different post-radiation time-points between 0. 5 h and 72 h after irradiation of 5 Gy in order to explore the time-effect. Results The expression of 3 genes at mRNA level was up-regulated. A good dose-effect relationship was showed for COXⅠ and COX Ⅲ at dose range of 0-3 Gy and 0-8 Gy for COX Ⅱ ( F COXⅠ=116. 62, FCOXⅡ = 17. 89, FCOXⅢ = 8.20, P ＜ 0. 05). For the time-effect after irradiation, the gene expression levels of COX Ⅱ and COX Ⅲ genes were up-regulated and the peak change occurred at 4 h after irradiation. For COX Ⅰ gene, the mRNA expression levels were down-regulated during 0.5-72 h( FCOXⅠ =31.99, FCOXⅡ = 19.47, FCOXⅢ = 20. 64, P ＜0. 05 ). At the protein level, the levels of COX Ⅰ and COX Ⅱ were lowered in lower doses and enhanced in higher doses, and the levels of COX Ⅲ were decreased at all dose levels (FCOX Ⅰ = 16.96, FCOXⅡ = 32.5, FCOXⅢ = 6. 51, P ＜ 0. 05 ). The protein levels of COX Ⅰ and COX Ⅱ were enhanced during 4-72 h and 8-72 h respectively after 5 Gy irradiation ( FCOX Ⅰ = 14.68,FCOXⅡ = 17. 18, FCOXⅢ =2. 52, P ＜0. 05). The activities of COX were lowered at different dose levels and different time-points. Conclusions Ionizing radiation might induce the changes in mitochondrial COX Ⅰ,COX Ⅱ and COX Ⅲ gene expression, and lead to the reduction of the COX activities.
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Objective To explore the changes of human mitochondrial COXI,ND1 and ND6 genes expression induced by ionizing irradiation.Methods Changes of human COXI,ND1 and ND6 gene expression were detected by RT-PCR and Real-time PCR 8 h after the irradiation in human lymphoblastoid cell lines,which were exposed to 1-10 Gy 60Co γ-rays.And the dose-effect relationships between expression changes of the genes and the doses were analyzed.The changes of these three genes expression were also analyzed at different post-radiation time-points between 0.5 h and 72 h after irradiation of 5 Gy in order to explore the time-effect.Results The expression of three genes COXI,ND1 and ND6,showed either the dose-effect or the time-effect after irradiation.The gene expression levels of three genes up-regulated generally and the peak change time-point was 4 h after irradiation.Conclusion Ionizing radiation,msht induce the changes of mitochondrial gene expression,and the gene expression level is up-regulated.
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Objective To establish the immortalized cell lines of peripheral blood lymphocytes for old male residents in high background radiation area(HBRA)in Guangdong,China,in order to preserve the specific genomic resources of residents in HBRA for the further genetic and molecular biological study on HBRA.Methods The peripheral blood samples of 20 old male residents in HBRA were collected after informed consent.The immortalized B lymphoblastoid cell lines,2 for each resident,were established with Epstein-Barr virus.After being frozen and recovered,the cell viability,the contamination of bacterium and mycoplaama were analyzed.The stabilization of cell lines was decided by comparing the karyotypes of the peripheral blood lymphocytes and the cell lines.Results 40 cell lines for 20 residents in HBRA were successfully established.The recovery rate of cell lines after being frozen was 100%.All the cell viablity after recovery was higher than 90%.and no contamination of bacteria and mycoplasma occurred.The karyotypes of the 20th generation cell lines were not change.Conclusion The immortalized cell lines established in this study could provide biological resources for further study on genetics and molecular biology in HBRA.
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Objective To explore if the occupational exposure to low dose thorium could induce adaptive response in peripheral lymphocytes.Methods 40 individuals.who exposed to thorium and rare earth mixed dust(exposure group) or control in Baotou Steel Plant, were selected, and chromosome aberrations were analyzed.Then the peripheral blood samples were irradiated in vitro with 2 Gy60Co γ-rays,and unstable chromosome aberration or DNA stand breakage analysis using single cell gel electrophoresis was performed. Results The dicentrics before 2 Gy exposure in exposure group was higher than that in control(P>0.05). But the dicentries after 2 Gy exposure in exposure group was lower than that in control,but not significantly (P>0.05).The tricentrics in exposure group was significantly lower than that in control(U=3.1622, 0.0ol<P<0.002).The DNA strand breakage in control group was significantly higher than that in exposure group(t=25,P<0.001).Conclusions Occupational exposure to low dose thorium could induce the adaptive response on chromosome aberration and DNA strand breakage in peripheral lymphocytes.