辐照诱导的人正常肝细胞系HL-7702细胞延迟效应

利用X射线辐照人正常肝细胞系HL-7702细胞, 运用胞质分离阻滞微核法实验检测细胞微核率,AnnexinV FITC细胞凋亡检测试剂盒检测细胞凋亡率, 细胞微核率和凋亡率随着辐照剂量的增加而显著增加。X射线照射后细胞传代培养, 第7代时不同剂量辐照后子代细胞微核率和凋亡率同未辐照细胞相比已无明显区别。 对不同剂量辐照后传代7代的细胞再次照射2.5 Gy的相同剂量,发现它们细胞微核率和凋亡率存在明显差异,即初次受辐照剂量高的细胞, 再次以相同剂量辐照后的微核率和凋亡率也高. 这些结果表明,X射线辐照导致了HL-7702细胞基因组不稳定性这一辐射延迟效应,再次辐照使得辐射的延迟效应得以明显的表现。 Human normal liver cell line HL-7702 cells were irradiated with different doses of X rays. Micronucleus and apoptosis rates in the irradiated cells were measured with cytokinesis block micronucleus method and Annexin V FITC apoptosis detection kit, respectively. Experimental data showed that the micronucleus and apoptosis rates increased obviously with increasing irradiation dose. After seven population doublings, the micronucleus and apoptosis rates of the cells surviving exposure to the X rays reduced to the same levels as non irradiated control cells; the progenies of the cells were secondly exposed to X rays at the same dose of 2.5 Gy. We found that the progenies of the cells surviving the first irradiations of the various doses showed markedly differential micronucleus frequencies and apoptotic rates. Although the same dose of 2.5 Gy was applied in the second irradiations, the micronucleus frequencies and apoptotic rates of the progenies of the cells initially exposed at higher doses were significantly higher than the others. These results indicate that X rays lead to genomic instability in HL 7702 cells, which is an important manifestation of radiation induced delayed effect, and a second radiation stimulus makes the delayed effect in the progeny of the previously irradiated cells be expressed obviously.     

低能N离子注入对蚕豆根尖细胞的诱变效应

为了研究低能N离子束的细胞遗传学效应, 以不同剂量的N离子束对蚕豆种子的种胚进行辐照, 观察分析根尖细胞的微核率、 有丝分裂指数和染色体畸变效应。 研究发现, 离子束的注入抑制了根尖细胞的有丝分裂, 干扰了正常的有丝分裂过程, 引发了染色体的结构、 行为和数目畸变; 随着离子注入剂量的增加, 微核率增加、 有丝分裂指数降低、 染色体畸变率增加。 In order to study the cytogenetic effects of low energy nitrogen ion irradiation, broad bean seed embryo was irradiated by different doses of nitrogen ions. Micronucleus rate, mitotic index and chromosome aberration in root tip cells were analyzed. The results showed that the injection of ions inhibited mitosis of root tip cells, interfered the normal process of mitosis, caused aberrations of chromosome structure, behavior and number. The frequency of micronucleus and chromosomal aberrations increased with the increasing radiation dosage, while mitotic index decreased.     

12C6+离子对阿维链霉菌累进辐照诱变效应研究

选用12C6+ 离子束对阿维链霉菌诱变选育高产菌株与原始菌株进行辐照诱变, 研究其累进辐照效应。实验结果表明,在辐照剂量为10 Gy时, 原始菌株比诱变高产菌株存活率高, 抗辐射能力强;辐照剂量高于30 Gy时,诱变高产菌株比原始菌株存活率高, 抗辐射能力强。原始菌株正突变率最高的辐照剂量为50 Gy, 致死率99.43%,正突变率最高, 达34.2%;对诱变高产菌株辐照剂量为30 Gy,致死率94.97%,正突变率最高, 达23.5% 。累进辐照效应降低了最佳辐照剂量。 Mutagenic effect on the mutant high producing strain ZJAV Y1 203 and the original strain ZJAV A1 irradiated by ion beam of 12C6+ have been investigated. The experimental results indicated that the original strain has higher survival rate and stronger resistance to radiation than mutant high producing Strain at dose of 10 Gy. The mutant high producing strain has higher survival rate and stronger resistance to radiation than the original strain at the dose higher than 30 Gy. The lethality was 97% and the highest rate of orthomutation was 34.2%, when ZJAV A1 was irradiated by 50 Gy 12C6+ beam. The lethality was 94.97% and the highest rate of orthomutation was 23.5% when ZJAV Y1 203 was irradiated by 30 Gy 12C6+ beam. The best radiation dose is decreased by progressivity irradiation.     

低剂量辐射超敏感性研究进展

细胞低剂量辐射反应是目前国际上研究的热点。 介绍了哺乳动物细胞的低剂量反应——辐射超敏感性(HRS)和增强的辐射抗性(IRR), 即细胞在大约0.1 Gy时会出现单位剂量细胞杀伤增强现象, 随着剂量的升高, 细胞的IRR增强, 到1 Gy以上细胞存活符合线性平方模型。 评述了近年来国际上低剂量HRS领域的研究进展, 着重讨论了HRS/IRR可能的分子机理及辐射传能线密度与HRS/IRR的关系, 并对HRS/IRR在肿瘤临床放射治疗中的应用做了初步的探讨, 最后提出了该领域进一步研究的一些问题。At present, cell response to low dose radiation is attracting growing interests all over the world. Hyper radiosensitivity (HRS) and increased radioresistance (IRR) were introduced in this paper. This phenomenon means that an excess cell killing per unit dose appears at about 0.1 Gy (HRS) and then the cell radiation sensitivity increases with increasing dose (IRR). When the dose outstrips 1 Gy, the cell surviving fraction coincides with the value predicted by the commonly accepted linear quadratic (LQ) model. We further reviewed the progress to date in the study of low dose HRS, especially the possible molecular mechanisms underlying HRS/IRR and the relationship between HRS/IRR and linear energy transfer (LET). An initial insight into the clinical application of HRS/IRR in tumor radiotherapy was presented as well.Moreover, several topics concerning the HRS/IRR investigation, which deserved to be reinforced, were put forward.     

重离子束对北里链霉菌的诱变效应

考察不同剂量重离子束对北里链霉菌的致死及诱变效应, 可确定最有利于筛选高产菌株的重离子束辐照剂量。 利用不同剂量的重离子束辐照北里链霉菌孢子, 统计了存活率、 致死率、 正负突变率。 结果发现, 在5 Gy重离子辐照时北里链霉菌出现较高致死率, 其后随剂量升高, 致死率变化较平缓。 各辐照剂量下正负突变率相比较, 40 Gy时正突变率最高, 负突变率相对较低, 存活率为0.92%。 因此确定40 Gy是对北里链霉菌高产菌株筛选最有利的辐照剂量。 To define the optimum dose of heavy ion beams for selecting high productive strains, we should study mortality and mutation effects of Streptomyces kitasatoensis irradiated by heavy ion beams in diffe rent doses. In this research, spores of Streptomyces kitasatoensis were irradiated by heavy ion beams with different doses. And survival rate, mortality rate, positive mutation and negative mutation were analyzed statistically. The results showed that high mortality rate appeared from 5 Gy and then the mortality rate curve became gently. Compared the positive and negative mutations in different doses, highest positive mutation was obtained in 40 Gy, while the negative mutation was lower in this dose, and the survival rate was 0.92%. So we defined that optimum dose of heavy ions radiation for Streptomyces kitasatoensis selection was 40 Gy in this experiment.     

低剂量辐射诱导hepG2细胞克隆存活和细胞周期适应性反应

以低剂量γ射线(0.05 Gy)预照射人肝癌细胞hep G2, 8 h后再用高剂量(3 Gy)照射, 测定了细胞的克隆存活率和细胞周期。 结果表明, 低剂量辐射预处理可诱导hep G2细胞产生克隆存活适应性反应, 并且有助于细胞通过G2/M期阻滞; 低剂量辐射诱导的克隆存活适应性反应与增强的通过细胞周期阻滞的能力之间有一定的相关性。 Human hepatoma cells hep G2 were irradiated with 3 Gy of γ ray 8 hours after primed with 0.05 Gy of γ ray, thereafter,cell survival and cell cycle were determined. The results indicated that both survival adaptive response and the enhanced ability to overcome G2/M arrest could be induced by pre irradiation with low dose of γ ray. It is suggested that there is a certain correlation between the survival adaptive response and the enhanced ability to overcome cell cycle arrest.     

12C6+束辐照引起的实验猪皮肤急性损伤反应的研究

探讨了正常皮肤对重离子辐照急性损伤反应的耐受性, 为重离子治癌临床应用提供安全性检测的实验依据。实验前10 min, 实验猪肌肉注射复方氯胺酮1.2 mg/kg进行麻醉, 然后在兰州重离子研究装置（HIRFL）辐照终端利用12C6+束照射, 辐照剂量分别为0, 12, 21和27 Gy, 辐照分3次完成, 剂量率约为1.2 Gy/min, Bragg峰区照射, 辐照后每隔7 d对照射野拍照并活检取样, 做HE组织病理学观察。不同剂量12C6+离子束辐照实验猪皮肤后, 皮肤外观反应随辐照剂量增大而加快, 表现为肿胀和色素沉积等; 皮肤组织结构的变化明显, 上皮细胞排列紊乱、 萎缩、 空泡变性; 基本恢复正常所需时间也越长, 且都存在明显的剂量效应关系。结果表明, 辐照剂量范围为0—27 Gy时, 重离子对正常皮肤的辐照是安全的。The tolerance of the normal skin to the acute radiation injury reaction induced by heavy ion beams has been studied experimentally. The experimental pigs were injected with 1.2 mg/kg ketamine in 10 min before irradiation and were irradiated with 0, 12 , 21 and 27 Gy 12C6+ ion at a dose rate of 1.2 Gy/min at the Heavy Ion Research Facility in Lanzhou（HIRFL）. The total radiation dose was finished by 3 times at Bragg Peak Region of Heavy Ion Beams.The radiation fields of skin were taken photo and performed biopsy. The contaneous tissues of radiation fields were stained by HE and examined histopatholo gical changes every seven days after irradiation. The results indicated that the cutaneous appearance reaction became more faster with radiation dosage rising and presented with swollen, melanin forming and so on after irradiated by the carbon ions at different dosage. The Pathological examination showed noticeable changes in histological and structural of experimental pigs skin, such as atrophy, vacuolation, denaturation and arranged irregularly in epithelial cells. Furthermore, the time for return to normality became longer with the increasing of radiation dosage. All indexes demonstrated correlation between the does and effects. It is concluded that the irradiation of heavy ion beams to normal skin is security when the radiation dose range is about 0—27 Gy.     

二烯丙基二硫对12C6+离子束辐照损伤小鼠的保护作用研究

研究大蒜素重要活性成分二烯丙基二硫( Diallyl disulfide, 简称DADS) 对12C6+离子束辐照损伤小鼠的保护作用。利用4 Gy 剂量12C6+离子束对不同浓度DADS 预处理的雄性昆明小鼠进行单次全身照射。随后检测骨髓细胞微核率和肝组织中丙二醛(MDA) 含量、蛋白质总羰基含量、总抗氧化能力( TAOC)及谷丙转氨酶(ALT ) 活性。结果显示,与单纯照射组相比,低浓度DADS 预处理组骨髓细胞微核率和肝组织ALT 活性均显著降低(p<0.001),而肝组织T-AOC明显增强( p < 0.05 );中浓度DADS 预处理组肝组织中MDA 含量和蛋白质总羰基含量均显著减少( p < 0.05 )。结果提示,DADS通过抑制氧化应激,有效地保护了脂质、蛋白质和遗传物质免受12C6+离子束辐照引起的损伤。The radioprotective effect of Diallyl disulfide (DADS) on 12C6+ ion irradiation was studied. Pretreated with DADS of different concentration, male Kung-Ming mice were exposed to whole body irradiation with dosage of 4 Gy 12C6+ ion. The animals were sacrificed after irradiation. Then the bone marrow cells micronucleus rate, malondialdehyde (MDA) levels, content of protein carbonylation, total antioxidant capacity ( T-AOC) and alanine aminotransferase ( ALT ) activity were measured. As compared with those in irradiated group, the ratio of micronucleus cells in marrow and the hepatic ALT activity in the pretreatment group with low dose DADS decreased significantly ( p < 0.001 ). Similarly,the content of protein carbonylation and the levels of MDA droped dramatically in the group with middle dose DADS treatment ( p < 0.05 ). On the contrary, the hepatic T-AOC increased markedly in the group of pretreatment with low dose DADS ( p < 0.05 ). The results showed that DADS protect lipoid, protein and genetic material from 12C6+ ion irradiation by right of resisting oxidative stress.     

大分割碳离子放射治疗中相对生物学效应与剂量依赖关系的研究

应用碳离子束进行大分割放射治疗从而缩短治疗周期是碳离子束治疗的优势之一。为研究大分割放疗增加单次照射剂量后,碳离子束相对生物学效应（RBE）的变化,应用细胞存活线性平方（LQ）模型推导出RBE与剂量的依赖关系。基于此关系研究了具有不同辐射敏感性的肿瘤细胞和正常组织细胞RBE随剂量的变化。结果表明,在0~20 Gy范围内,不论肿瘤细胞与正常组织细胞具有怎样的辐射敏感性,肿瘤细胞的RBE值始终大于正常组织细胞。此外,基于理论推导和对相关实验数据的分析,证实了RBE随剂量增加而递增现象的存在。这些结果对应用碳离子束进行大分割放射治疗具有重要的指导作用。Short treatment course due to the suitability of hypofractionated regimen for carbon ion beam is one of the advantages of carbon ion radiotherapy. To study the dependence of relative biological effectiveness (RBE) on dose, the relationship between RBE and dose was deduced through the linear-quadratic (LQ) model. Based on the relationship, the change of RBE of tumor cells and normal tissue cells with different radiosensitivities with dose was studied. The results showed that the RBE value of tumor cells was always greater than that of normal tissue cells in the dose range of 0~20 Gy, regardless of the radiosensitivity of tumor and normal tissue cells. In addition, based on theoretical deduction and analysis of the relevant experimental data, the existence of RBE increase with increasing dose was verified. These results are of great significance for conducting hypofractionated radiotherapy with carbon ion beam.     

A study on the best irradiation dose of X-ray for Hep-2 cells by Fourier transform infrared spectroscopy

Fourier transform infrared spectroscopy (FTIR) was employed to study the human epidermis larynx car- cinoma cell lines (Hep-2) which were irradiated by different doses of X-ray.The results show that (1) the irradiation of X-ray damages the structure of the CH_3 groups of the thymine in DNA,which restrains the reproduction of Hep-2 cells effectively,(2) the 8 Gy dose of X-ray irradiation changes the framework and the relative contents of some proteins,lipids and the nucleic acid molecules intercellular in the greatest degree,and (3) the 8 Gy dose of X-ray irradiation is the best irradiation dose for lowering the degree of the cancerization of Hep-2 cells according to the criteria for the degree of the cancerization reported recently.Meanwhile,the apoptosis of these cells were detected by using flow cytometry (FCM) primarily. It shows that the apoptotic ratio of the Hep-2 cells depends on the irradiation dose to some extent,but is not linearly.And the apoptotic ratio of the 12 Gy dose group is the maximum (20.36%),but the apoptotic ratios of the 2 to 8 Gy dose groups change little.     

细胞松弛素B阻断微核法鉴定男性个体辐射敏感性的方法初探

初步研究了男性个体辐射敏感性的鉴定方法及标准。采集50名男性志愿者的外周血，分别给予不同剂量X射线照射，采用细胞松弛素B阻断双核法测定微核率(MNF)，通过二阶多项拟合法，绘制微核剂量效应选项中心标准曲线，将个人微核剂量效应曲线与标准曲线比对后判断个体辐射敏感性。 $0.0\sim2.5 $ Gy剂量范围内，剂量效应二阶多项拟合的中心方程为(MNF=0.014 7+0.036 2D+0.023 1D 2， r=0.726)。50名志愿者中，辐射敏感的有13人，辐射抗性的有14人，基本符合正态分布。Spearman秩和相关分析结果显示，MNF在各个辐射剂量点与辐射敏感性均存在正相关,与辐射抗性呈负相关,MNF随剂量增加而增加。本研究初步建立了“以线代点”男性个体辐射敏感性鉴定方法,并发现男性外周血淋巴细胞的本底微核率与个体辐射敏感性呈正相关。     

~(12)C~(6+)离子束辐照紫苏干种子当代效应

利用兰州重离子研究装置(HIRFL)提供的12C6+离子束辐照紫苏干种子(辐照剂量为40,80和120Gy,剂量率4Gy/min),探讨了重离子束辐照对紫苏M1代的生物学效应。结果发现,经不同剂量的12C6+离子束辐照后,紫苏种子的发芽率、发芽势、存活率、株高、分枝数、单株产量和千粒重等生物学性状均发生了变化,其中发芽势、单株产量和千粒重随辐照剂量的提高而降低,且有明显的剂量效应关系,但发芽率、大田成活率、株高和分枝数却随辐照剂量的增大,呈现出明显的"抛物线"趋势;紫苏幼苗根尖细胞的微核率和染色体畸变率随辐照剂量增加呈线性增加关系。这表明:12C6+重离子束辐照紫苏种子,具有明显的当代损伤效应,在本试验剂量范围内,低剂量辐照对发芽率和成活率有促进作用。     

甲基化抑制剂5-氮杂2′-脱氧胞苷对三维培养A549细胞辐射敏感性的影响

为探讨DNA去甲基化试剂5-氮杂-2′-脱氧胞苷(5-aza-2′-deoxycytidine,5-Aza-CdR)对三维(3D)培养模式下的肺腺癌细胞A549辐射敏感性的作用,开展了系列实验。使用不同浓度5-Aza-CdR处理单层(2D)A549细胞72 h后,MTT法检测其对A549细胞的增殖抑制作用。选取低浓度(2,5μmol/L)5-Aza-CdR预处理2D和3D培养的A549细胞72 h,X射线分别辐照1,2,4,6 Gy,检测微核形成率和克隆存活。实验结果显示,不同浓度的5-Aza-CdR均能抑制2D的A549细胞增殖,且呈剂量依赖性。5μmol/L药物预处理2D与3D细胞并联合辐照后诱导的细胞微核形成率均显著高于相应的对照组,并且细胞存活率显著降低。不过,较低浓度5-Aza-CdR(2μmol/L)预处理的3D培养A549细胞4,6 Gy辐照后微核数目较未用药处理组显著增加,克隆存活率较未用药组显著降低(P0.05),而在2D培养A549细胞中未观测到上述现象。研究结果表明,5-Aza-CdR能抑制A549细胞增殖,3D培养A549细胞药物预处理更能增加其辐射敏感性。结果暗示,为减少对正常细胞的毒性作用,在临床放疗中,可低剂量使用5-Aza-CdR,实现肿瘤的有效靶向治疗。     

~(12)C~(6+)离子辐照对苜蓿M1代低温胁迫存活率、过氧化氢酶及过氧化物酶活性的影响

研究了不同剂量12C6+离子辐照对中兰1号、BC-04-477、塔城3种苜蓿M1代个体在低温胁迫下存活率、过氧化氢酶(CAT)及过氧化物酶(POD)活性的影响。在辐照剂量为400 Gy时,中兰1号低温胁迫组存活率、CAT活性比未辐照的对照分别提高了33.3%,56.3%,POD活性与未辐照的对照无差异;在辐照剂量为400 Gy时,BC-04-477低温胁迫组存活率、CAT及POD活性比未辐照的对照组分别提高了33.3%,69.2%,5.1%;塔城在辐照剂量为800 Gy时,低温胁迫组的存活率、CAT及POD活性比未辐照的对照组分别提高了25%,26%,22.8%。以上结果表明,12C6+离子辐照可以提高中兰1号、BC-04-477、塔城的低温环境的存活能力,提高苜蓿抗寒性能。     

12C和X射线辐照人肺癌细胞H1299的生物学效应

用高传能线密度（LET）的12C离子束和低LET的X射线辐照体外培养的非小细胞肺癌H1299(p53基因缺失), 研究它们的辐照生物学效应的差异。 用克隆形成率法测定了细胞对射线的辐射敏感性; 用AnnexinV/PI试剂盒检测了细胞早期凋亡; 用流式细胞仪检测了细胞周期变化。 实验结果表明, 12C离子束辐照H1299细胞的存活率明显低于用X射线辐照的; 12C离子束引起H1299细胞的早期凋亡率明显高于X射线辐照引起的, 且持续时间更长; 12C离子束引起的H1299细胞G2/M期的抑制更明显。 说明H1299细胞对高LET的12C离子束的辐射敏感性高于对X射线的, 重离子对p53基因缺失型肿瘤的治疗可实施较低的照射剂量、 较少的照射次数和较长的时间间隔。     

高功率微波辐照对雄性大鼠生殖细胞的影响

 采用激光扫描共聚焦显微镜观察受不同参数高功率微波辐照后的大鼠精子细胞内Ca²⁺的变化，同时观察了辐照后大鼠的生殖细胞微核率、畸形率、精子数量、存活率和顶体酶反应的变化。实验表明：此条件下的高功率微波辐照对雄性大鼠的生殖细胞微核率和畸形率没有明显的损伤效应，但4×10⁵次脉冲的高功率微波辐照对大鼠的顶体酶反应有较明显的抑制作用，可能通过改变细胞内第二信使的Ca²⁺浓度来影响其生殖细胞功能。