Human lymphocyte damage and phosphorylation of H2AX and ATM induced by γ-rays

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.     

不同剂量60Co γ 射线部分照射人离体血对染色体畸变形成的影响

目的 分析不同剂量60Co γ射线部分照射人离体血对淋巴细胞染色体畸变形成的影响.方法 用0～8 Gy(剂量率为0.35 Gy/min)60Coγ射线在37 ℃条件下照射3份离体健康人外周血标本,以0.5∶1的比例与同一供血者的未受照血混合,120 min后进行培养、制片,显微镜下分析染色体畸变(双着丝粒+着丝粒环)的变化,借此进行剂量估算.结果 各组的双着丝粒体+着丝粒环和总畸变,以及断片和单体断裂均随着剂量的增加而增加.用双着丝粒+着丝粒环进行的剂量估算,0.5～2 Gy组大于照射剂量的1/3,4～8 Gy组均接近照射剂量的1/3.结论 染色体畸变可以作为估算非均匀照射的生物学指标之一.

Abstract：

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.     

60Co γ射线照射致小鼠肝脏的miRNAs表达改变

目的 应用miRNA芯片筛选4 Gy60Co γ射线照射后小鼠肝脏中差异表达的miRNAs,生物信息学方法探索差异表达miRNAs调控的主要功能.方法 SPF级C57BL/6J小鼠接受4 Gy60Co γ射线单次全身照射后,进行外周血白细胞计数和骨髓嗜多染红细胞微核计数.应用miRNA芯片筛选照射后小鼠肝脏中差异表达的miRNAs,用miRNA特异引物对部分差异表达miRNA进行实时定量PCR(real time PCR)验证.运用生物信息学方法,对差异miRNAs靶基因及调控功能进行预测.结果 4 Gyγ射线照射后,外周血白细胞总数与对照组相比显著减少(t=2.87,P＜0.05),而骨髓嗜多染红细胞微核率与对照组相比显著增加(t=-2.91,P＜0.05).miRNA芯片结果显示,照射组与对照组差异表达的miRNAs共17个,其中9个表达上调,8个表达下调.miR-124和miR-34a的实时荧光定量RT-PCR验证结果与芯片结果一致.GO分析发现,与黏附、细胞周期相关的通路被抑制,一些免疫相关通路被激活.结论 miR-34a和miR-194参与了急性辐射损伤的调控,起主要调控作用的miRNAs还有miR-124、miR-382和miR-92a*.

Abstract：

Objective To investigate the differential expression profiles of microRNAs in the liver of 60Co γ-ray irradiated mice using microRNA microarray and to explore their main functions by bioinformatic analysis.Methods After SPF C57BL/6J mice expose to 4 Gy-single whole body radiation,total number of peripheral WBC and the fMNPCE were measured at 3 d.The differentially expressed miRNAs in mouse liver were detected with miRNA microarray,miRNA-124 and miR-34a were confirmed by real time RT-PCR assay.Bioinformatic analysis was applied to explore target genes and the main functions of the differential expressed miRNAs.Results Compared with control group,the total number of peripheral WBC decreased( t = 2.87,P ＜ 0.05 ) ,while the fMNPCE in bone marrow increased ( t =-2.91,P ＜0.05) after 4 Gy γ-ray irradiation.miRNA microarray revealed that 17 miRNAs were differentially expressed,in which 9 up-regulated,8 down-regulated.The expression levels of miR-124 and miR-34a were coincident with the result of real time RT-PCR.GO analysis showed that some pathways including adherens junction and cell cycle were suppressed,while some immune-related pathways were activated.Conclusions miR-34a and miR-194 were involved in the regulation of acute radiation damage,some other miRNAs including miR-124、miR-382 and miR-92a* also played important roles in radiation process.     

香兰素衍生物VND3207对小鼠骨髓细胞遗传损伤的防护效应研究

Objective To study the protection of vanillin derivative VND3207 on the cytogenetic damage of mouse bone marrow cell induced by ionizing radiation.Methods BALB/c mice were randomly divided into five groups:normal control group,2 Gy dose irradiation group,and three groups of 2 Gy irradiaiton with VND3207 protection at doses of 10,50 and 100 mg/kg,respectively.VND3207 was given by intragastric administration once a day for five days.Two hours after the last drug administration,the mice were irradiated with 2 Gy γ-rays.The changes of polychromatophilic erythroblasts micronuclei (MN),chromosome aberration (CA) and mitosis index (MI) of mouse bone marrow cells were observed at 24 and 48 h after irradiation.Results Under the protection of VND3207 at the dosages 10,50,100 mg/kg,the yields of poly-chromatophilic erythroblasts MN and CA of bone marrow cells were significantly decreased(t = 2.36-4.26,P ＜ 0.05),and the marrow cells MI remained much higher level compared with the irradiated mice without drug protection (t = 2.58,2.01,P ＜ 0.05).The radiological protection effect was drug dose-dependent,and the administration of VND3207 at the dosage of 100 mg/kg resulted in reduction by 50% and 65% in the yields of MN and CA,respectively.Conclusions VND3207 had a good protection effect of on γ-ray induced cytogentic damage of mouse bone marrow cells.     

氮氧自由基R-1对人肝细胞L-02的辐射防护作用

Objcetive To investigate the protective effects of the nitroxides R-1 on human liver cells exposed to ionizing radiation.Methods Human liver cells L-02 were cultured and irradiated with 60Co γ-rays at the doses of 0,1,2,4,and 8 Gy,in order to screen the proper irradiation dose.WR2721 at the terminal concentration of 4 mmol/L was used as positive control.L-02 cells irradiated with 4 Gy were added with R-1 at the terminal concentration of 0.25 μmol/L at 30 min before irradiation or immediately after irradiation.MIT method was used to screen the proper conditions for follow-up experiment 72 h later.L-02 cell culture fluid was added with R-1 at the concentrations of 0,0.125,0.25,0.5,and 1 μmol/L,respectively for 30 min before irradiation at the doses of 0,1,2,4,and 8 Gy to ealculate clone formation rate at 10 d post-irradiation.L-02 cells were cultured and divided into 4 groups:control group without any treatment.drug group pretreated by 0.25 μmol/L R-1 only,irradiation group,irradiated at 4 Gy only,and drug + irradiation group with combination of 0.25 μmol/L R-01 and 4 Gy irradiation.The inverted microscopy and Hoechst 33258 staining and flow eytometry were used to observe the apoptosis of the cells at 24,48,and 72 h later.Results Nitroxides R-1 did not inhibit the viability of L-02 cell when its concentration was less than 1 μmol/L and it inhibited the L-02 cell growth when the concentration wu higher than 2 μmoL/L.The A value and colony formation rate of different concentration of R-1 groups were all higher than those of the irradiation group,and the effect of the 0.25 μmol/L drug concentration group was the most significant.Consequently,the concentration 0.25 μmoL/L was selected for follow-up experiment.Compared with the irradiation group,the L-02 cells of the pretreatment group showed solid adherence, increased refraction,clear outline,less apoptotic and dead cells at 4 Gy post-irradiation.Conclusions Nitroxides R-1 can protect the human liver cells from 60Coγ-ray induced injury effectively.The mechanism of its protective effect may be the reduction of apoptosis.     

慢性镉染毒及联合辐射对大鼠的基因毒性作用

目的 探讨慢性镉染毒及联合辐射对大鼠的基因毒性.方法 雄性SD大鼠分设空白对照组、0.1 mg CdCl2·kg-1·d-1低剂量镉染毒组、0.5 mg CdCl2·kg-1·d-1高剂量镉染毒组、单纯照射组、低剂量镉染毒+照射组和高剂量镉染毒+照射组.腹腔注射镉染毒连续8周,1次/d,然后给予2 Gy γ照射.于照射后第10天或受照即日后继续染镉4周,心脏取血,采用多核细胞法检测外周血淋巴细胞微核率和hprt基因突变率,同时检测外周血白细胞数量变化和血镉含量.结果 大鼠低剂量镉染毒8周和12周组未观察到外周血细胞损伤,而辐射诱导的微核率(F=26.74,P<0.01和F=14.13,P＜0.05)和hprt基因突变率(F=6.60,P＜0.05)显著降低;高剂量镉染毒8周和12周组与空白对照组比较,外周血白细胞数显著增高(F=8.74,P＜0.01和F=13.11,P=0.000),淋巴细胞微核率(F=26.74,P＜0.05和F=14.13,P=0.000)和hprt基因突变率(F=6.60,P＜0.05和F=12.83,P＜0.05)明显增加,而高剂量镉染毒+照射组的基因毒性又显著高于单纯高剂量镉染毒组或单纯照射组,表现出联合毒性效应.结论 慢性、低剂量镉染毒诱导外周血淋巴细胞对辐射产生适应性效应,血镉浓度增加到613～678 μg/L时能刺激白细胞显著增加并与辐射联合作用加重对淋巴细胞的基因毒性.

Abstract：

objective To investigate the effects of chronic cadmium exposure and cadmium exposure combined with γ-ray irradiation on the peripheral lymphocytes and their genotoxicity on hprt gene.Methods Ninety-six SD rats were randomly divided into 6 equal groups:①normal control group,②lowdose cadmium exposure group undergoing intraperitoneal injection of 0.1 mg CdCl2·kg-1·d-1 for 8 weeks,③high-dose cadmium exposure group undergoing intraperitoneal injection of 0.5 mg CdCl2·kg-1·d-1 for 8 weeks,④pure irradiation group exposed to whole-body γ-ray irradiation at the dose of 2 Gy for one time,⑤low-dose cadmium exposure combined with irradiation group undergoing intraperitoneal injection of 0.1 mg CdCl2·kg-1·d-1 for 8 weeks and then whole-body 2 Gy γ-ray irradiation,and ⑥high-dose cadmium exposure combined with whole-body 2 Gy γ-ray irradiation group undergoing intraperitoneal injection of 0.5 mg CdCl2·kg-1·d-1 for 8 weeks and then whole-body 2 Gy γ-ray irradiation.Ten days after the irradiation cardiac blood samples were collected from some of the rats to culture the peripheral lymphocytes to detect the micronucleus rate and hprt mutant frequency of lymphocytes bv multinucleated cell assay.The other rats underwent continuous Cd exposure for 4 weeks after γ-ray irradiation and then cardiac blood samples were collected to detect the micronucleus rate and hprt mutant frequencv of lymphocytes.Meanwhile,the amount of white blood cells(WBC)was counted and the blood cadmium concentration was measured by ICP-MS.Results The numbers of WBC in the peripheral blood at different time points of the high dose cadmium group were significantly higher than those of the normal control group(F=8.74.P<0.01 and F=13.11,P=0.000).The micronucleus rate at difierent time points of the pure irradiation group were significantly higher than those of the control group( F = 26. 74 ,P =0. 000 and F = 14. 13, P = 0. 000). The micronucleus rates of the high-dose cadmium group were significantly higher than those of the control group( F = 26. 74 ,P <0. 05 and F = 14. 13 ,P = 0. 000 ). The micronucleus rates of the low-dose cadmium + irradiation group were significantly lower than those of the pure irradiation group( F = 26. 74, P < 0. 01 and F = 14. 13, P < 0. 05 ). The micronucleus rates of the highdose cadmium + irradiation group were significantly higher than those of the pure irradiation group ( F =26.74,P =0. 000 and F = 14. 13 ,P =0. 000). The hprt mutation rates at different time points of the pure irradiation group were significantly higher than those of the normal control group( F = 6.60, P < 0. 01 and F = 12.83 ,P = 0. 001 ). The hprt mutation rates of the high-dose cadmium group were significantly higher than those of the control group ( F = 6. 60, P < 0. 05 and F = 12.83, P < 0.05 ), but not significantly different from those of the pure irradiation group. However, the hprt mutation rates of the high-dose cadmium + irradiation group were significantly higher than those of the pure irradiation ( F = 12. 83, P =0. 000) and high-dose cadmium group( F = 6.60,P < 0.05 and F = 12. 83, P < 0.05 ). The hprt mutation rates of the low-dose cadmium + irradiation group were significantly lower than those of the pure irradiation ( F = 6. 60, P < 0. 05 ) , but not significantly different from those of the control group. Conclusions Chronic exposure to low dose cadmium induces the adaptive response of lymphocytes to radiation. The cadmium in blood at the level of 613-678 μg/L induces leukocytosis and chronic exposure to high dose cadmium combined with irradiation leads to increased genotoxicity of lymphocytes.     

香兰素衍生物VND3207对不同LET辐射致质粒DNA损伤的防护作用

目的 评价不同LET辐射致DNA损伤以及药物的防护作用.方法 分别以60Co γ射线、质子束、7Li重离子束照射溶液状态超螺旋构象质粒DNA,通过琼脂糖凝胶电泳分析DNA分子构象变化,检测DNA损伤程度及VND3207的防护作用.结果 质子和7Li重离子体外所致质粒DNA损伤明显比γ射线严重.药物VND3207能够有效减轻所观察的3种不同LET辐射对质粒DNA的损伤,加药组与不加药组相比,质粒DNA开环构象显著减少,保护效果随着药物浓度的增加更加明显.200 μmol/L浓度对50 Gy γ射线、质粒和7Li重离子辐照质粒DNA损伤的保护效果(质粒超螺旋构象百分比)分别为85.3%(t=3.70,P=0.033)、73.3%(t=10.58,P=0.017)和80.4%(t=8.57,P=0.008).可见VND3207对重离子辐射损伤的保护效应尤为显著,明显优于质子辐照损伤.结论 药物VND3207对辐射DNA损伤具有较好的保护作用,特别是对γ射线和重离子辐射损伤的保护作用更为明显.

Abstract：

Objective To evaluate the radioprotective effect of vanillin derivative VND3207 on DNA damage induced by different LET ionizing radiation.Methods The plasmid DNA in liquid was irradiated by 60Co γ-rays, proton or 7Li heavy ion with or without VND3207.The conformation changes of plasmid DNA were assessed by agarose gel electrophoresis and the quantification was done using gel imaging system.Results The DNA damage induced by proton and 7Li heavy ion was much more serious as compared with that by 60Co γ-rays, and the vanillin derivative VND3207 could efficiently decrease the DNA damage induced by all three types of irradiation sources, which was expressed as a significantly reduced ratio of open circular form (OC) of plasmid DNA.The radioprotective effect of VND3207 increased with the increasing of drug concentration.The protective efficiencies of 200 μmol/L VND3207 were 85.3% (t =3.70,P =0.033), 73.3% (t = 10.58, P =0.017)and 80.4% (t =8.57,P =0.008)on DNA damage induction by 50 Gy of γ-rays, proton and 7Li heavy ion, respectively.It seemed that the radioprotection of VND3207 was more effective on DNA damage induced by high LET heavy ion than that by proton.Conclusions VND3207 has a protective effect against the genotoxicity of different LET ionizing radiation, especially for γ-rays and 7 Li heavy ion.     

γ射线诱发人外周血淋巴细胞T细胞受体基因突变剂量-效应和时间-效应关系

目的 初步建立T细胞受体(TCR)突变频率的剂量-效应和时间-效应模型,为探讨TCR作为估算辐射生物剂量计提供依据.方法 将10名健康成年人的外周血淋巴细胞分成两组.第1组4人(男性)的外周血淋巴细胞分别给予0、0.5、1.0、1.5、2.0、2.5、3.0、3.5、4.0和5.0 Gv γ射线照射,用于拟合剂量-效应曲线,第2组6人(男女各半)的外周血淋巴细胞给予2 Gy γ射线照射,用于拟合时间-效应曲线.用流式细胞仪进行计数检测,计算TCR基因突变频率.结果 γ射线照射诱发TCR MF的辐射剂量-效应曲线,拟合最佳的模型为二次方程模型:TCR MF=92.14+22·61D2(R2adj=0.65);γ射线照射诱发TCR MF的辐射时间-效应曲线,拟合最佳的模型为二次多项式方程模型:TCR MF=3.74+743.66T+308.64T2(R2adj=0.79).结论 0～5 Gy范围内TCR基因突变频率与辐射剂量存在剂量-效应关系.照后4 d内TCR基因突变频率随时间的延长而继续增加,存在时间-效应关系.

Abstract：

Objective To study the dose-effect relationship and time-effect relationship of T cell receptor (TCR) gene mutation induced by γ-rays in lymphocytes of human peripheral blood.Methods Samples of peripheral blood were collected from 10 healthy adults and lymphocytes were separated.Four samples from males used to fit time-effect curve were exposed to γ-rays at the doses of 0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,and 5.0 Gy,respectively,and 6 samples from 3 males and 3 females used to fit dose-effect curves were exposed to γ-rays of the dose of 2 Gy.Flow cytometry was used to detect the mutation frequency of TCR gene (TCR MF).Radiation dose-effect curves and time-effect curves were fitted and optimal mathematical models were selected respectively.Results The optimal mathematical model for radiation dose-effect was quadratic equation model:TCR MF = 92.14 + 22.61D2 (R2adj = 0.65).The optimal mathematical model for radiation time-effect was quadratic polynomial equation model:TCR MF = 3.74 + 743.66T + 308.64T2 (R2adj = 0.79).Conclusions TCR MF is increased as the γ-rayirradiation dose increases within the range of 0-5 Gy,and TCR MF is increased with the lapse of time within the range of 4 days after γ-ray radiation.     

氮氧自由基R-1对人肝细胞L-02的辐射防护作用

目的 探讨氮氧自由基R-1(简称R-1)对人肝细胞L-02的辐射防护作用.方法 在L-02细胞培养液中,加入终浓度为0、0.125、0.25、0.5、1、2、4、8、16、32μmol/L的R-1,作用24、48和72 h.用MTT法测定R-1的毒性作用,以筛选合适的R-1浓度.后续实验选择0.125、0.25、0.5、1 μmol/L 4个浓度组检测其防护作用.设终浓度4 mmol/L的细胞保护剂WR2721为阳性对照组.采用60Coγ射线照射,吸收剂量为0、1、2、4、8 Gy,照射72 h后,进行MTT比色法.L-02细胞分为2组:照射前30 min加药组和照射后立即加药组.终浓度均为0.25 μmol/L,吸收剂量为4 Gy,照射后72 h进行MTT比色实验.照射后10 d,用克隆形成实验检测不同浓度的R-1对L-02细胞活力的影响.选用防护效果最佳的0.25μmol/L浓度对细胞进行预处理,分别在4 Gy照射后的24、48和72 h,用倒置显微镜观察细胞形态的变化,Hoechst 33258荧光染色法和流式细胞仪检测细胞凋亡.结果 当R-1浓度低于1 μmoL/L时,与0 μmol/L组相比,L-02细胞各时间点的吸光度(A)值无明显变化;而浓度高于2 μmol/L时,与0 μmol/L组相比,其A值随浓度的增高而下降.选用0、0.125、0.25、0.5、1μmol/L的浓度组.与照射组相比,R-1各浓度组的A值和克隆形成率明显提高,其中0.25μmol/L组的作用最明显.与照射组相比,0.25 μmol/L预处理组的L-02细胞贴壁好,折光性强,轮廓清晰,凋亡细胞和死亡细胞明显较少.结论 R-1能有效地防护60Coγ射线对L-02细胞的辐射损伤,其防护作用可能与减少细胞凋亡有关.

Abstract：

Objcetive To investigate the protective effects of the nitroxides R-1 on human liver cells exposed to ionizing radiation.Methods Human liver cells L-02 were cultured and irradiated with 60Co γ-rays at the doses of 0,1,2,4,and 8 Gy,in order to screen the proper irradiation dose.WR2721 at the terminal concentration of 4 mmol/L was used as positive control.L-02 cells irradiated with 4 Gy were added with R-1 at the terminal concentration of 0.25 μmol/L at 30 min before irradiation or immediately after irradiation.MIT method was used to screen the proper conditions for follow-up experiment 72 h later.L-02 cell culture fluid was added with R-1 at the concentrations of 0,0.125,0.25,0.5,and 1 μmol/L,respectively for 30 min before irradiation at the doses of 0,1,2,4,and 8 Gy to ealculate clone formation rate at 10 d post-irradiation.L-02 cells were cultured and divided into 4 groups:control group without any treatment.drug group pretreated by 0.25 μmol/L R-1 only,irradiation group,irradiated at 4 Gy only,and drug + irradiation group with combination of 0.25 μmol/L R-01 and 4 Gy irradiation.The inverted microscopy and Hoechst 33258 staining and flow eytometry were used to observe the apoptosis of the cells at 24,48,and 72 h later.Results Nitroxides R-1 did not inhibit the viability of L-02 cell when its concentration was less than 1 μmol/L and it inhibited the L-02 cell growth when the concentration wu higher than 2 μmoL/L.The A value and colony formation rate of different concentration of R-1 groups were all higher than those of the irradiation group,and the effect of the 0.25 μmol/L drug concentration group was the most significant.Consequently,the concentration 0.25 μmoL/L was selected for follow-up experiment.Compared with the irradiation group,the L-02 cells of the pretreatment group showed solid adherence, increased refraction,clear outline,less apoptotic and dead cells at 4 Gy post-irradiation.Conclusions Nitroxides R-1 can protect the human liver cells from 60Coγ-ray induced injury effectively.The mechanism of its protective effect may be the reduction of apoptosis.     

Studies on mechanism of treatment of granulocyte colony-stimulating factor,recombinant human interleukin-11 and recombinant human interleukin-2 on hematopoietic injuries induced by 4.5 Gy γ-rays irradiation in beagles

Objective To investigate the mechanism of treatment of granulocyte colony-stimulating factor(rhG-CSF),recombinant human interleukin-11(rhIL-11)and recombinant human interleukin-2 (rhIL-2)on hematopoietic injuries induced by 4.5 Gy60 Coγ-ray irradiation in beagles,and to provide experimental evidence for the clinical treatment of extremely severe myeloid acute radiation sickness (ARS).Methods Sixteen beagle dogs were given 4.5 Gy60 Co γ-ray total body irradiation(TBI),then randomly assigned into irradiation control group,supportive care group or cytokines+supportive care (abbreviated as cytokines)group.In addition to supportive care,rhG-CSF,rhlL-11 and rhIL-2 were administered subcutaneously to treat dogs in cytokines group.The percentage of CD34+cells,cell cycle and apoptosis of nucleated cells in peripheral blood were examined by Flow cytometry.Results After 4.5 Gy 60 Co γ-ray irradiation,the CD34+cells in peripheral blood declined obviously(61.3%and 52.1% of baseline for irradiation control and supportive care group separately).The cell proportion of nucleated cells in Go/G1 phase was increased notably(99.27% and 99.49% respectively).The rate of apoptosis(26.93% and 21.29% separately)and necrosis(3.27% and 4.14%,respectively)of nucleated cells were elevated significantly when compared with values before irradiation(P<0.05) 1 d post irradiation.When beagles were treated with cytokines and supportive care,the CD34+cells in peripheral blood were markedly increased(135.6% of baseline).The effect of G0/G1 phase blockage of nucleated cells became more serious(99.71%).The rate of apoptosis(5.66%)and necrosis(1.60%)of nucleated cells were significantly lower than that of irradiation control and supportive care groups 1 d after exposure.Conclusions Cytokines maybe mobilize CD34+cells in bone marrow to peripheral blood,indce cell cycle block at G0/G1 phase and reduce apoptosis,and eventually cure hematopoieticinjuries induced by irradiation.     

辐射诱导人外周血淋巴细胞DNA损伤反应相关基因表达变化的实验研究

目的 采用实时定量PCR技术,检测人外周血淋巴细胞DNA损伤反应相关基因表达对X射线全身照射的反应,为探索新型辐射生物标志物奠定基础.方法 以吸收剂量为0、1、2、3、4、5 Gy X射线照射正常人外周血,在照射后4和24 h,应用实时定量PCR法,对淋巴细胞细胞周期素依赖性蛋白激酶抑制物蛋白1a(Cdknla)、生长阻滞和DNA损伤基因45a(Gadd45α)基因的表达变化进行检测.应用胞质分裂阻滞微核法(CB微核法),检测淋巴细胞微核率变化.结果 Cdknla基因在人外周血淋巴细胞受到1～5 Gy照射后4和24 h,其相对表达量均较对照组显著性升高,至4 Gy达到峰值,5 Gy后不再继续增加.Cdknla基因表达与照射剂量呈线性相关(r=0.946、0.975,P<0.05).Gadd45ct基因在1～5 Gy照后4和24 h,其相对表达量均呈剂量依赖性升高,且照射后4 h的表达高于24 h(r=0.936、0.797,P<0.05).CB微核法中,在1～5 Gy X射线照射后4和24 h,各剂量组淋巴细胞微核率均显著增多,呈现良好的线性关系(r=0.990、0.984,P<0.05).结论 辐射使Cdknla基因和Gadd45α基因表达上调,表现出较好的剂量线性关系,有可能成为研制新型辐射生物剂量计的候选基因.

Abstract：

Objective To detect the expression of DNA damage response genes induced by radiation in human peripheral blood lymphocyte,and to explore the new biomarkers of radiation.Methods The human peripheral blood cells were irradiated to X-rays at different doses of 0,1,2,3,4,and 5 Gy.The quantitative real.time qPCR wag used to detect the expressions of cyclin-dependent kinase inhibitor l a gene(Cdknl a)and growth arrest and DNA damage inducible gene(Gadd45a)in lymphoeytes at 4 and 24 h post-irradiation,respectively.The method of CB mieronucleus was used to determine the change of micronucleus ratio.Results The expression of Cdknl a in peripheral blood lymphocytes wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy.reached the peak at 4 Gy and began to decrease at 5 Gy,which showed a dose-dependent manner(r=0.946,0.975,P<0.05).Similarly,the expression of Gadd45α in human peripheral blood lymphocytes was also increased significantly at 4 and 24 h post-irradiation to 0-5 Gy in a dose-dependent manner,while the expression of Gadd45a at 4 h wag higher than that at 24 h(r=0.936,0.797,P<0.05).The ratio of micronuclei wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy(r=0.990,0.984,P<0.05).Conciusions Cdknl a and Gadd45α expression could be increaged significandy at 4 and 24 h post-irradiation to 0-5 Gy,showing a good linear relationship.which might be candidate for radiation biological dosimeter.     

Studies on mechanism of treatment of granulocyte colony-stimulating factor,recombinant human interleukin-11 and recombinant human interleukin-2 on hematopoietic injuries induced by 4.5 Gy γ-rays irradiation in beagles

Objective To investigate the mechanism of treatment of granulocyte colony-stimulating factor(rhG-CSF),recombinant human interleukin-11(rhIL-11)and recombinant human interleukin-2 (rhIL-2)on hematopoietic injuries induced by 4.5 Gy60 Coγ-ray irradiation in beagles,and to provide experimental evidence for the clinical treatment of extremely severe myeloid acute radiation sickness (ARS).Methods Sixteen beagle dogs were given 4.5 Gy60 Co γ-ray total body irradiation(TBI),then randomly assigned into irradiation control group,supportive care group or cytokines+supportive care (abbreviated as cytokines)group.In addition to supportive care,rhG-CSF,rhlL-11 and rhIL-2 were administered subcutaneously to treat dogs in cytokines group.The percentage of CD34+cells,cell cycle and apoptosis of nucleated cells in peripheral blood were examined by Flow cytometry.Results After 4.5 Gy 60 Co γ-ray irradiation,the CD34+cells in peripheral blood declined obviously(61.3%and 52.1% of baseline for irradiation control and supportive care group separately).The cell proportion of nucleated cells in Go/G1 phase was increased notably(99.27% and 99.49% respectively).The rate of apoptosis(26.93% and 21.29% separately)and necrosis(3.27% and 4.14%,respectively)of nucleated cells were elevated significantly when compared with values before irradiation(P<0.05) 1 d post irradiation.When beagles were treated with cytokines and supportive care,the CD34+cells in peripheral blood were markedly increased(135.6% of baseline).The effect of G0/G1 phase blockage of nucleated cells became more serious(99.71%).The rate of apoptosis(5.66%)and necrosis(1.60%)of nucleated cells were significantly lower than that of irradiation control and supportive care groups 1 d after exposure.Conclusions Cytokines maybe mobilize CD34+cells in bone marrow to peripheral blood,indce cell cycle block at G0/G1 phase and reduce apoptosis,and eventually cure hematopoieticinjuries induced by irradiation.     

穿心莲内酯对大鼠辐射损伤防护的实验研究

Objective To explore the effects of andrographolide(AP),extracted from the traditional Chinese herb Andrographlis paniculata(AP),on injury induced by radiation exposure.Methods Sixty male rats were randomly divided into 4 equal groups and irradiated with 60Co γ-rays at the doses of 1,2,and 4 Gy,respectively:low dose AP group(intragnstrically administered with AP at the dose of 100 ms/kg daily for 10 d before irradiation),and high dose AP group(intragastrically administered with AP at the dose of 200 ms/kg daily for 10 d before irradiation),model group(administered with the same volume of normal saline instead of AP for 10 d before irradiation),and control group(irradiated only at 3 different doses).One day after irradiation all rats were killed with their livers being fixed to make paraffin section.The morphological feature was observed under light microscope after HE staining,and the cell apoptosis was detected by TUNEL technology.Results Compared to the control and model groups,the pathological changes of liver were significantly gentler in the AP treatment groups.The apoptosis rates of the liver cells of all the AP sub-groups were significantly lower than those of the control and model subgroup(t=2.19-4.80.P<0.05).Conclusions AP might have prevention effect against radiation exposure.     

成骨细胞促进急性放射损伤小鼠骨髓造血系统及血管恢复的研究

目的 探讨成骨细胞对放射损伤小鼠骨髓造血系统及血管恢复的影响.方法 取18只雄性BALB/c小鼠股骨制备成骨细胞,其余42只小鼠随机分成健康对照组、成骨细胞组和生理盐水组3组.健康对照组不做任何处理;成骨细胞组和生理盐水组小鼠于6.0 Gy 60 Co γ射线一次性全身均匀照射后,分别经尾静脉输入成骨细胞(2×106个/只)和等体积的生理盐水.于照射后第7、14和21天计数小鼠外周血细胞,骨髓单个核细胞并作骨髓组织学观察.采用流式细胞仪检测骨髓单个核细胞中CD34+细胞百分比,采用免疫组织化学方法检测小鼠骨髓微血管密度.结果 照射后第7、14和21天成骨细胞组小鼠外周血细胞和骨髓单个核细胞计数,骨髓单个核细胞中CD34+细胞百分比,骨髓组织造血面积及骨髓微血管密度均明显高于生理盐水组(t=2.46～64.51,P＜0.05).结论 成骨细胞能促进放射损伤小鼠骨髓造血系统及血管的恢复.

Abstract：

Objective To explore the effects of osteoblasts on the recovery of hematopoiesis and angiogenesis in acute irradiation injury mice.Methods The femurs of 18 male BALB/c mice were used to prepare the bone marrow osteoblasts, and the rest mice were divided into 3 groups as normal group, saline group and osteoblast group.The mice in normal group received no treatment, and the other two groups were received 6.0 Gy 60Co γ-ray irradiation.After irradiation each mouse of osteoblast group was administered with 2 × 106 osteoblasts through tail vein injection, and equal volume saline was given to each mouse of saline group by the same way.The following factors were measured at 7, 14, 21 d after irradiation, they were the counts of peripheral blood cells and bone marrow mononuclear cells ( BMMNC ) , the percentage of CD34 + cells in BMMNC, the histology changes and micro vascular density (MVD) of bone marrow tissue.Results The counts of peripheral blood cells, BMMNC and hematopoietic tissue area in osteoblast group were higher than those in saline group.The percentage of CD34 + cells in BMMNC and the MVD of bone marrow in osteoblast group were also higher than those in saline group at 7, 14, 21 d after irradiation ( t = 2.46 - 64.51, P ＜ 0.05 ).Conclusions Osteoblasts could significantly promote the recovery of hematopoiesis and angiogenesis in mice after acute irradiation injury.     

黄芪总黄酮对人体正常细胞和肿瘤细胞辐射防护作用的差异性研究

目的 研究黄芪总黄酮(total flayonoids of astragalus,TFA)对60°Co γ射线辐射损伤的人体正常骨髓间充质干细胞(human mesenchymal stem cells,hMSCs)和肝癌细胞HepG-2辐射防护作用的差异性.方法 MTT法检测TFA处理组与单纯照射组hMSCs和HepG-2的细胞活性;HepG-2细胞克隆形成实验检测细胞的辐射敏感性;流式细胞技术分析细胞凋亡率;Western blot技术分析凋亡相关蛋白Fas,Bcl-2,Bax的表达.结果 MTT检测结果显示,当给予6 Gy γ射线一次性照射后,TFA预处理组hMSCs细胞活性分别比单纯照射组提高了1.15～1.95倍;经相同浓度TFA预处理的肝癌细胞HepG-2的细胞活性仅为单纯照射组的53%～23%;TFA的给药浓度与细胞存活率(survival rate)之间显现出良好的量效关系.细胞克隆形成实验结果显示:TFA+照射组能够明显抑制HepG-2细胞增殖,作用强于单纯TFA给药组和单纯照射组.流式细胞分析表明,经6 Gy γ射线一次性照射6、24和48 h后,TFA预处理组hMSCs的细胞凋亡率分别为23.3%,11.2%和2.9%.单纯照射组hMSCs的细胞凋亡率相应为29.3%,24.9%和13.6%;TFA预处理组肝癌细胞HepG-2的细胞凋亡率分别为11.6%,17.3%和20.1%,单纯照射组HepG-2的细胞凋亡率分别为6.9%、9.3%和15.8%.Western blot分析显示,在肝癌细胞HepG-2中,TFA预处理照射组促凋亡蛋白Fas和Bax 的表达量显著高于单纯照射组和对照组(t=11.17～-2.8,-12.35～3.4,P＜0.05);凋亡抑制蛋白Bel-2的表达量,TFA预处理照射组明显低于单纯照射组和对照组(f<6.36～17.61.P<0.05).结论 TFA对人正常骨髓间充质细胞具有明显的放射防护作用,对肝癌细胞不仅没有放射防护作用反而具有凋亡促进作用;TFA对肝癌细胞的促凋亡作用,主要通过上调促凋亡蛋白Fas和Bax的表达与下调凋亡抑制蛋白Bcl-2的表达,从而大大增强了60 Co γ射线对肝癌细胞的凋亡诱导作用.

Abstract：

Objective To investigate the different radioprotective effects of total flavonoids of Astragalus (TFA) on human normal mesenchymal stem cells(hMSCs) and hepatoma cells injured by 60 Coγ-ray radiation.Methods hMSCs and HepG-2 cells were cultured and randomly divided into TFA-treated and untreated groups.The cells of different groups were irradiated with 60 Co γ-rays at the dose of 6 Gy.MTT method was utilized to detect the survival rates of the hMSCs and HepG-2 cells pretreated or untreated with TFA before irradiation.Cell clone formation test was used to measure the cellular radiosensitivity.The apoptosis rates of different groups were determined by flow cytometer assay.The expression rates of the apoptosis-promoting proteins Fas and Bax and the apoptosis-inhibiting protein Bcl-2 were analyzed by Western blotting.Results MTT showed that the survival rates of hMSCs pretreated by TFA were 1.15-1.95 times higher than that of the pure irradiation group.On the contrary,the survival rates of the TFA pretreated HepG-2 cells were only 0.53-0.23 times that of the pure irradiation group.There was a good dose-effect relationship between the cell survival rate and the TFA concentration.Cell clone formation rate indicated that combined treatment of TFA and radiation inhibited the cell proliferation more effectively than single TFA or pure radiation.Flow cytometry showed that 6,24 and,48 h post-irradiation to 6 Gy,the apoptosis rates of the hMSCs were 23.3% ,11.2% ,and 2.9% ,respectively in the TFA pretreated group and were 29.3% ,24.9% ,and 13.6% in the pure radiation group.However,the apoptosis rates of the HepG-2 cells at 6,24,and 48 h post-irradiation to 6 Gy were 11.6% ,17.3% ,and 20.1% ,respectively in the TFA pretreated group and were 6.9% ,9.3% ,and 15.8% ,respectively in the direct radiation group.Western blotting showed that the expression levels of Fas and Bax proteins in the HepG-2 cells were significantly higher in the TFA pretreated group than in the pure radiation group.On the contrary,the expression level of the apoptosis inhibiting protein Bcl-2 was significantly lower in the TFA pretreated group than in the pure radiation group.Conclusions TFA has obvious effects of radiological protection on human hMSCs and has no effects of radiological protection but effects of apoptosis enhancement on hepatoma cells.The promotion of apoptosis of TFA on hepatoma cells is primarily through increasing the expression of apoptotic proteins such as Fas and Bax and reducing the expression of anti-apoptotic protein Bcl-2.     

粒细胞集落刺激因子对急性辐射损伤小鼠中枢及外周血淋巴细胞亚群重建的影响

目的 观察粒细胞集落刺激因子(G-CSF)对急性辐射损伤小鼠中枢及外周血淋巴细胞亚群重建的影响.方法 雌性BALB/c小鼠60只经6 Gy照射后随机分为照射组、G-CSF+照射组.G-CSF+照射组小鼠给与重组人G-CSF 100μg·kg-1·d-1皮下注射,连续14 d,照射组小鼠给与等体积磷酸盐缓冲液(PBS)皮下注射,连续14 d,另设空白对照组小鼠20只.照后7、14、21和28d颈部脱臼处死小鼠,取出胸腺制成单个核细胞悬液,使用流式细胞仪检测胸腺CD4+CD8+、CD4+CD8-、CD4-CD8+、CD4-CD8-细胞亚群的比例.使用全血细胞计数仪进行外周血白细胞计数及淋巴细胞绝对值测定,流式细胞仪检测照后14、28、60 d外周血淋巴细胞亚群比例,CCK-8法检测脂多糖(LPS)、刀豆蛋白A(ConA)刺激后脾脏淋巴细胞增殖指数.结果 照后7 d胸腺CD4+CD8+细胞比例降至最低,14 d出现反弹,21 d再次下降,以后逐渐恢复.照后28 d G-CSF+照射组CD4+CD8+细胞比例恢复正常并高于照射组(t=12.22,P＜0.05).照后21 d G-CSF+照射组CD4-CD8+细胞比例亦明显高于照射组(t=3.77,P＜0.05).照后7 d外周血白细胞及淋巴细胞绝对值降至最低,照后14和60 d,G-CSF+照射组CD3+CD8+T细胞比例明显高于照射组(t=4.31,5.78,P＜0.05),但两组间CD3+CD4+T细胞比例在各时间点无明显差异.G-CSF+照射组B淋巴细胞比例在照后14 d明显低于照射组(t=7.3,P＜0.05),但很快恢复,照后28和60 d两组B淋巴细胞比例差异无统计学意义.照后14 d,G-CSF+照射组脾脏淋巴细胞对LPS、ConA刺激的增殖指数分别为照射组的4.37和2.98倍.结论 G-CSF可促进照后胸腺细胞亚群的恢复,提高外周血淋巴细胞数量,调节外周血淋巴细胞亚群比例,提高淋巴细胞增殖功能,促进急性辐射损伤后中枢及外周免疫重建.

Abstract：

Objective To investigate the effects of recombinant human granulocyte colonystimulating factor(G-CSF) on central and peripheral lymphocyte subset reconstitution after a sublethal dose of irradiation. Methods Sixty female BALB/c mice were given a 6.0 Gy γ-ray total body irradiation (TBI) and randomly divided into 2 equal groups. The mice in G-CSF + TBI group were injected subcutaneously with recombinant human G-CSF 100 μg·kg-1·d-1 for 14 d and the mice in TBI group were injected subcutaneously with the same volume of phosphate buffered solution (PBS) once daily for 14 d. 7,14,21, and 28 d later the mice were killed and their thymus were taken out to prepare of the mononuclear cell suspension to analysis the percentage of thymic CD4 + CD8 + double positive, CD4 +CD8 - single positive, CD4 - CD8 + single positive and CD4 - CD8 - double negtive cells by flow cytometry. Peripheral blood samples were collected from the caudal vein twice a week, and the white blood cell(WBC) counts and absolute number of lymphocytes were assessed by automatic hemocyte analyzer. 14,28, and 60 d later blood samples were collected from angular vein to examine the peripheral lymphocyte subsets by flow cytometry. Cell counting kit-8 was used to detect lipopolysaccharide (LPS) or concanavalin A (ConA) stimulated splenic lymphocyte proliferation. Results The percentage of thymic CD4 + CD8 +double positive cells decreased 7 d after irradiation, rebounded at 14 d, decreased again at 21 d, and then got a permanent recovery. 28 d after irradiation the percentage of thymic CD4 + CD8 + double positive cells in the G-CSF + TBI group recovered to normal and was significantly higher than that of the TBI group (t =12. 22, P < 0. 05). 21d after irradiation the percentage of thymic CD4-CD8 + single positive cells of the G-CSF + TBI group was significantly higher than that of the TBI group (t = 3.77, P < 0. 05). The peripheral WBCs and lymphocytes decreased to the lowest levels 7 d after irradiation and then gradually increased, however, WBCs and lymphoeytes of the G-CSF + TBI group began to recover earlier and faster than the TBI group. The proportion of CD3 + CD8 + T cells of the G-CSF + TBI group was significantly higher than that of the TBI group 14 and 60 d after irradiation (t =4. 31,5.78, P <0.05). But there was no significant difference in the proportion of CD3 + CD4 + T cells between the two groups. The proportion of B lymphoeytes of the G-CSF + TBI group was significantly lower than that of the TBI group 14 d after irradiation(t =7.30, P <0.05), but it recovered quickly, and there were no significant differences in the proportion of B lymphoeytes between the two groups 28 and 60 d after irradiation. The proliferation indexes of splenic lymphocytes in response to LPS and ConA in the G-CSF + TBI group were 4. 37 and 2.98 times higher than those in the TBI group 14 d after irradiation. Conclusions G-CSF could accelerate the recovery of central and peripheral lymphocyte subsets, raise the absolute number of lymphocytes, and enhance their proliferative function, which contributes to the central and peripheral immune reconstitution after acute irradiation.