低剂量电离辐射诱导小鼠胸腺细胞凋亡及细胞周期进程适应性反应的时间效应

目的：观察低剂量辐射诱导胸腺细胞凋亡及细胞周期进程适应性反应的基本规律。方法：实验用X射线照射昆明雄性小鼠,其诱导剂量（D1）及其后攻击剂量（D2）分别是75mGy和1．5Gy。D1和D2间隔时间分别是3、6、12、24和60h。通过流式细胞仪检测胸腺细胞凋亡和细胞周期进程的变化。结果：当D1和D2间隔3、6和12h ,D1 D2组胸腺细胞凋亡百发数明显低于D2组（P＜0．05）,G0／G1和G2＋M期细胞百分数也不同程度地低于D2组,而S期是分数却明显高于D2组（P＜0．0．5或P＜0．01）。结论上述结果指出,D1在75mGy,吸收剂量率为12．5mGy／min,D2在1．5Gy,吸收剂量率为0．287Gy／min;D1和D2间隔3－12h,可在全身照射条件下诱导小鼠胸腺细胞凋亡和细胞周期进程的适应性反应。     

低剂量辐射诱导小鼠胸腺细胞RIP28的分离及磷酸化特性

低剂量辐射诱导小鼠胸腺细胞ＲＩＰ２８的分离及磷酸化特性陈沙力孟庆勇刘树铮低剂量辐射可在动物和人体诱发出兴奋效应的多种及多层次的表现，已被广泛证实［１］。以往的研究表明，７５ｍＧｙＸ射线全身照射可影响小鼠胸腺细胞蛋白分子表达，包括表达上调或下调及新蛋白...     

X射线全身照射对小鼠胸腺细胞GADD45及Rb蛋白表达的影响

细胞凋亡是机体维持内环境稳态的重要过程，多种大分子物质的合成是大多数细胞凋亡所必需。ＧＡＤＤ４５和Ｒｂ蛋白与细胞凋亡和死亡密切相关，在某种程度上决定了细胞周期的进程。电离辐射可诱导细胞凋亡，本研究探讨不同剂量Ｘ射线对ＧＡＤＤ４５和Ｒｂ蛋白表达的影响，...     

低剂量辐射诱导小鼠胸腺细胞及其亚组的适应性反应

目的研究低剂量辐射预先照射以及随后大剂量照射后小鼠胸腺细胞Ｔ细胞受体（ＴＣＲ）、ＣＤ３、ＣＤ４和ＣＤ８分子表达的变化。方法ＴＣＲ、ＣＤ３表达采用间接荧光流式细胞术检测,ＣＤ４、ＣＤ８表达采用双参数直接免疫荧光流式细胞术检测。结果实验结果表明：单纯１５ＧｙＸ射线全身照射后ＴＣＲ,ＣＤ３阳性细胞数以及ＣＤ４－Ｄ８－,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋细胞数明显减少,当１５ＧｙＸ射线全身照射前６小时预先照射００７５Ｇｙ时,可明显减轻其后１５Ｇｙ照射对ＴＣＲ＋,ＣＤ３＋,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋的损伤作用。表现为各亚组细胞数显著高于单纯１５Ｇｙ照射组。ＣＤ４－ＣＤ８－亚组的细胞数无明显变化。结论００７５ＧｙＸ射线全身照射能够诱导胸腺细胞ＴＣＲ＋,ＣＤ３＋,ＣＤ４＋ＣＤ８＋,ＣＤ４＋ＣＤ８－和ＣＤ４－ＣＤ８＋亚组细胞的适应性反应。     

低剂量辐射诱导胸腺细胞凋亡的适应性反应

低剂量电离辐射对机体的影响是当前国内外放射生物学界研究的重要内容。阐明低剂量电离辐射生物效应及其适应性反应 ,对放射生物学理论和辐射防护实践均具有重要意义。我室通过流行病学调查和大量的实验研究证实 ,低剂量辐射可增强免疫功能 [1],降低胸腺细胞凋亡 [2 ],具有与高剂量辐射迥然不同的细胞和分子机理[3 ]。低剂量辐射可诱导适应性反应 ,已得到确认[4]。在此基础上 ,我们进一步观察了低剂量辐射诱导小鼠胸腺细胞凋亡适应性反应的剂量、剂量率和时间效应 ,以阐明低剂量辐射诱导适应性反应的规律 ,为深入探讨其机理提供有意义的实验…     

小鼠胸腺和牌细胞对淋巴因子反应的辐射剂量效应关系

作者研究了Ｃ５７ＢＬ／６小鼠经０．１～８．０ＧｙＸ射线全身照射后淋巴因子效应细胞反应性的变化．结果发现，照后２４小时胸腺细胞对ＩＬ－１反应的剂量效应曲线由两个斜率不同的成分组成，其Ｄ３７，分别为１．６５和４．０９Ｇｙ；照后１２和２４小时脾细胞对ＩＬ－２反应的Ｄ３７分别为５．５８和３．４６Ｇｙ；ＣＴＬＬ－２细胞在为０．５～１０Ｇｙ剂量范围内，对ＩＬ－２反应性呈剂量依赖性降低，Ｄ３７为８．７７Ｇｙ。提示ＩＬ－２效应细胞的辐射抗性高于ＩＬ－１效应细胞．     

电离辐射对胸腺细胞及脾细胞p16、CyclinD1、CDK4蛋白表达的影响

目的　研究电离辐射对小鼠胸腺细胞及脾细胞中p16、CyclinD1及CDK4蛋白表达的影响。方法　采用单克隆抗体免疫荧光标记及流式细胞术检测蛋白表达的变化。结果　时效实验证实 ,2 0GyX射线全身照射后 8,2 4及 48h ,胸腺细胞p16蛋白表达显著增高 (分别P <0 0 5、P <0 0 1及P <0 0 5) ;照射后 2 4h ,脾细胞p16蛋白表达显著增高 (P <0 0 5)。然而 ,照射后 8～ 2 4h ,胸腺细胞CDK4蛋白表达显著降低 (P <0 0 5～P <0 0 1) ;照射后 8～ 72h ,脾细胞CDK4蛋白表达显著降低(P <0 0 5～P <0 0 1)。量效实验证实 ,1 0 ,2 0及 4 0Gy全身照射后 2 4h ,胸腺细胞及脾细胞p16蛋白表达均显著增高 (P <0 0 5～P <0 0 1)。然而 ,2 0Gy照射后胸腺细胞CDK4蛋白表达显著降低(P <0 0 5) ;0 5～ 6 0Gy照射后脾细胞CDK4蛋白表达显著降低 (P <0 0 5～P <0 0 1)。研究还发现 ,胸腺细胞及脾细胞中CyclinD1蛋白表达于照射后均明显降低。结论　电离辐射可诱导胸腺细胞及脾细胞中p16蛋白表达增高。p16 CyclinD1 CDK4通路可能在X射线诱导胸腺细胞G1期阻滞中起重要作用     

电离辐射对胸腺细胞p16/CyclinD/CDK4基因转录和蛋白表达的影响

电离辐射可诱导细胞发生G1期阻滞，其意义在于使受损伤的DNA得以修复，维持细胞基因组稳定性。目前研究发现主要有两条负向调控通路：p53-p21／pRb通路和p16-CyclinD／CDK4-pRb通路在G1→S期转换中起重要作用。以往的实验结果证实p53-p21通路在中等剂量电离辐射诱导的G1期阻滞中起重要作用。然而，电离辐射对体内细胞     

裂变中子诱导小鼠胸腺细胞凋亡的时间效应及其分子机制 …

目的：以＾６０Ｃｏγ射线为参比射线,研究裂变中子诱导小鼠胸腺细胞凋亡的时间效应,并初步探讨其分子机制。方法：用形态学观察、ＤＮＡ电泳、流式细胞仪（ＦＣ,）分析及二苯胺（ＤＰＡ）法检测细胞凋亡;用斑点杂交方法检测ｐ５３与ｂｃｌ－２的基因表达,结果：小鼠经裂变中子２．５Ｇｈ照射后２－２４ｈ,在各时间点上均检测到胸腺细胞ＤＮＡ梯状条带,利用光镜与电镜观察到具有典型凋亡特征的胸腺细胞;以ＤＮＡ法、ＦＣＭ分     

低剂量辐射诱导小鼠脾细胞蛋白表达及生物活性

目的：为了探讨低剂量辐射兴奋效应的分子机理,本文作者对昆明小鼠接受７５ｍＧｙＸ射线全身照射后４ｈ的脾细胞进行了蛋白分子表达的研究。方法用凝胶过滤和高效液相色谱法（ＨＰＬＣ）分析蛋白分子表达,通过＾３Ｈ－ＴｄＲ掺入的淋巴细胞转化和人外周血淋巴细胞染色体畸变率观察蛋白分子表达的生物活性。结果发现相对分子质量为１７００００、１８５００和５００００ ３种蛋白质的表达在照射后发生改变,这３种蛋白质分别在脾细     

X射线对小鼠胸腺细胞凋亡的影响

采用荧光分光光度法对裂解ＤＮＡ进行定量，并用琼脂糖凝胶电泳法定性研究Ｘ射线全身照射后小鼠胸腺细胞凋亡。结果表明，４ＧｙＸ射线照后２小时胸腺细胞凋亡开始增加，于照后１４小时达峰值，尔后呈下降趋势。ＤＮＡ裂解率在照后２４小时降至１４小时的５０％，这可能是内环境中巨噬细胞吞噬凋亡小体所致。在照射后１４小时研究其剂量－效应关系发现，高剂量照射使ＤＮＡ裂解明显增多，形成１８０ｂｐ（ｂａｓｅｐａｉｒｓ）左右或其整倍数的ＤＮＡ断片，电泳呈现＂梯形图谱＂；而低剂量辐射可使ＤＮＡ裂解率降低。剂量－效应曲线呈Ｊ型。     

1．5Gy X射线全身照射对小鼠胸腺细胞CD_3、CD_4、CD_8分子表达及

采用单克隆抗体免疫荧光技术，流式细胞术检测，观察了１．５ＧｙＸ射线单次全身照射（剂量率０．２８６Ｇｙ／ｍｉｎ）对小鼠胸腺细胞ＣＤ３分子表达的影响，及胸腺细胞亚群和细胞周期的变化。结果表明，中等剂量照射后，胸腺细胞ＣＤ３分子的百分率明显增高，胸腺细胞ＣＤ３阳性细胞比例为对照组的１７７．６１％。同时，胸腺中ＣＤ４＋及ＣＤ８＋细胞比例亦显著增加，分别为对照的２０２．５％及１６５．８７％。然而，胸腺中ＣＤ４＋、ＣＤ８＋细胞的比例显著降低，为对照组的６８．２８％，与此同时，胸腺细胞周期中Ｓ期细胞比例明显降低，为对照组的５５．１４％。     

低剂量电离辐射对小鼠肺、胸腺和脾细胞分泌CSF的影响

本实验采用X射线对小鼠全身照射, 剂量率为12.5mGy/mIn, 剂量为25～250mGy。发现低剂过辐射能明显刺激肺和胸腺细胞分泌造血细胞集落刺激因子(Colony-stimulating factors,CSF)。胸腺细胞反应较为敏感，50mGy即能明显促进CSF分泌，250mGy时胸腺细胞分泌CSF活性水平仍明显高于对照(P<0.01)，且以50mGy剂量照射对其分泌CSF的刺激作用最强;肺组织细胞反应较弱，仅在75mGy剂量照射后.CSF分泌量明显增加(P<0.05):低剂量照射对脾细胞分泌CSF未见有明显的促进作用。75mGy照射后不同时间检测CSF,发现照射后2天肺和胸细胞分泌CSF量明显增加，直到照射后7天，CSF活性水平仍明显高于对照(P<0.01)，说明低剂量X射线全身照射能明显 促进肺和胸腺细胞分泌CSF，这对促进机体造血和免疫功能，增强机体抵抗力有重要的意义.     

X射线全身照射诱导小鼠胸腺Egr-1和Egr-4基因表达水平的实时定量RT-PCR分析

目的 应用实时定量RT-PCR技术检测X射线全身照射诱导小鼠胸腺Egr-1和Egr-4基因的表达变化。方法 小鼠接受X射线全身照射后4和24 h,提取胸腺mRNA,以GAPDH作为内参基因,利用实时定量RT-PCR检测方法,探讨Egr-1和Egr-4基因的相对表达量与不同照射剂量之间的关系。同时计数骨髓嗜多染红细胞微核率作为辐射生物剂量参照。结果 Egr-1和Egr-4基因表达量在0.5～6 Gy全身照射后4和24 h均与照射剂量之间存在显著的相关性(r =0.974,0.987,0.978,0.999, P＜0.01),其剂量效应曲线可拟合成线性平方方程。各剂量点Egr-1和Egr-4基因表达量与骨髓嗜多染红细胞微核率高度相关(r =0.866、0.947、0.983、0.835, P＜0.05)。进一步分析表明,照射后4 h Egr-4基因表达不仅剂量效应关系良好,且增幅最为明显,并与骨髓嗜多染红细胞微核率的剂量效应曲线相平行。结论 实时定量RT-PCR技术检测Egr-4基因的早期表达有可能成为建立大批量、快速辐射生物剂量估算方法的候选者。     

1.5Gy X射线全身照射对小鼠胸腺细胞CD、CD4、CD8分子表达及

采用单克隆抗体免疫荧光技术,流式细胞术检测,观察了1.5GyX射线单次全身照射(剂量率0.286Gy/min)对小鼠胸腺细胞CD₃分子表达的影响,及胸腺细胞亚群和细胞周期的变化。结果表明,中等剂量照射后,胸腺细胞CD₃分子的百分率明显增高,胸腺细胞CD₃阳性细胞比例为对照组的177.61%.同时,胸腺中CD₄⁺及CD₈⁺细胞比例亦显着增加,分别为对照的202.5%及165.87%.然而,胸腺中CD₄⁺、CD₈⁺细胞的比例显着降低,为对照组的68.28%,与此同时,胸腺细胞周期中S期细胞比例明显降低,为对照组的55.14%.     

Analysis of immune cell populations and cytokine profiles in murine splenocytes exposed to whole-body low-dose irradiation

Purpose: In contrast to high-dose therapeutic irradiation, definitive research detailing the physiological effects of low-dose irradiation is limited. Notably, the immunological response elicited after low-dose irradiation remains controversial.

Materials and methods: Female C57BL/6 mice were whole- body-irradiated with a single or three daily fractions up to a total dose of 0.1, 1, or 10 cGy. Blood and spleen were harvested 2, 7 and 14 days after irradiation.

Results: The splenic CD4⁺ T cell subpopulations were temporarily increased at 2 days after single or fractionated irradiation, whereas the percentage of dendritic cells (DC) and macrophages was decreased. Whereas CD8⁺ T cell populations were decreased in single-dose irradiated mice at day 7, early and sustained reduction of CD8⁺ T cell numbers was observed in fractionated- dose-irradiated mice from day 2 until day 14. In addition, single-dose irradiation resulted in a Th1 cytokine expression profile, whereas fractionated-dose irradiation drove a Th2 shift. Additionally, increased expression of immune-related factors was observed at early time-points with single-dose irradiation, in contrast to the dose-independent induction following fractionated-dose irradiation.

Conclusions: Our results demonstrate that low-dose irradiation modulates the immune response in mice, where the sensitivity and kinetics of the induced response vary according to the dosing method.     

Effect of low-dose X-rays on the liver of whole-body irradiated rats

Abstract

Purpose: To investigate the effect of whole-body low-dose radiation (10 cGy of 6?MV x-rays) given prior to a challenging dose of 2?Gy x-rays on adaptive response in the liver of rats

Material and methods: Rats were either irradiated with 10 cGy, 2?Gy or 10 cGy 24?h prior to 2?Gy (10 cGy–2?Gy irradiated). Liver samples were analyzed for apoptosis, caspase-3, Bcl-2, by flow cytometry. DNA damage was determined by alkaline comet assay. The protein damage, lipid damage, and expression of endogenous antioxidants, Il-1β, Il-6, and TNF-α were determined by ELISA.

Results: An increase in apoptosis paralleled with increase in DNA damage and expression of Il-1β, Il-6, and TNF-α, protein oxidation, and lipid peroxidation were detected in all irradiated groups. The irradiated rats with 10 cGy–2?Gy and the 2?Gy-irradiated showed the highest effect. The increase in oxidative damage of protein and lipid was accompanied with depletion of endogenous antioxidants. In all cases, the10 cGy–2?Gy irradiated group showed similar or higher effect than the 2?Gy-irradiated group.

Conclusions: Under the present experimental conditions, There is no evidence that 10 cGy-irradiation protected the liver cells against a subsequent higher dose. The significant effect of 10 cGy-irradiation emphasizes the low-dose radiation-associated risk.     

不同剂量X射线全身照射后胸腺细胞游离钙浓度的变化时程

目的研究Ｘ射线全身照射后胸腺细胞游离钙浓度的变化时程，以揭示低剂量辐射免疫增强效应的分子机理。方法应用Ｆｕｒａ－２ＡＭ荧光探针，采用荧光分光光度法检测了小鼠胸腺细胞内游离钙浓度。结果７５ｍＧｙ全身照射后可使细胞内游离钙浓度增高，２４小时达峰值，７２小时回降至对照水平。结论低剂量辐射可促进Ｔ淋巴细胞信号传递     

Comparison of the spectra of proteins synthesized in mouse thymocytes after irradiation or hydrocortisone treatment

The proteins synthesized in mouse thymocytes after irradiation and hydrocortisone treatment were analyzed by two-dimensional electrophoresis. An exposure to lympholytic agents induced different changes in the biosynthesis of proteins; however the induction of a few common proteins by these agents was revealed. The increase in the synthesis of five nuclear polypeptides occurred at early times (15-75 min) after irradiation. At least two of them (proteins of the nuclear matrix) are also induced by hydrocortisone. Synthesis of three of these 'early proteins' soon terminated, while the synthesis of the other two increased, and by 3.5 h they were found in large quantities after both treatments. At the same time, another protein common for both agents was induced. Three of these nuclear proteins are part of the nuclear matrix. Participation of these proteins in realization of the cell death program is discussed.