预防非典型肺炎方剂对小鼠外周血液淋巴细胞DNA损伤的影响

目的　研究预防非典型肺炎方剂对小鼠外周血液淋巴细胞 DNA的损伤作用。方法　应用单细胞凝胶电泳方法测定 6个预防非典型肺炎方剂体内给药对小鼠外周血液淋巴细胞 DNA损伤的作用。结果　ig给予预防非典型肺炎方剂 、 、 (1/ 3临床等效剂量、临床等效剂量、3倍临床等效剂量× 3 d)对小鼠外周血液淋巴细胞 DNA有明显的损伤作用 ,并呈剂量依赖关系。预防非典型肺炎方剂 、 、 (1/ 3临床等效剂量、临床等效剂量、3倍临床等效剂量× 3 d)对小鼠外周血液淋巴细胞 DNA没有明显的损伤作用。结论　预防非典型肺炎方剂 、 、 具有潜在的遗传毒性     

莲房原花青素对乙醇诱导的人胚肝细胞株L-02氧化损伤的保护作用

目的研究莲房原花青素(LSPC)对乙醇诱导的人胚肝细胞株L-02氧化损伤的保护作用。方法观察200mmol·L-1乙醇,5、10、25mg·L-1的LSPC,5、10、25mg·L-1的LSPC与200mmol·L-1乙醇共同作用于肝细胞L-02 24h后,运用单细胞凝胶电泳(SCGE)实验和微核实验(MNT)观察DNA和染色体损伤情况,用流式细胞术(FCM)分析凋亡率的变化以及活性氧探针(2,7-二氯荧光素)探测细胞内活性氧(ROS)水平的变化。结果 LSPC组与正常对照组比较,差异无显著性意义(P>0.05)。纯乙醇组与正常对照组比较,差异有显著性意义,与乙醇组相比,5mg·L-1和10mg·L-1LSPC能显著降低olive尾矩(OTM)、微核率(MNF)、凋亡率和ROS的水平(均P<0.05),但高剂量组(25mg·L-1)对乙醇引起的肝细胞损伤保护作用不明显。结论适量浓度的莲房原花青素对乙醇诱导的肝细胞L-02的氧化损伤有保护作用。其机制可能与LSPC的抗氧化活性有关。     

Ethanol enhanced the genotoxicity of acrylamide in human, metabolically competent HepG2 cells by CYP2E1 induction and glutathione depletion

In the present study, the genotoxicity of acrylamide (AA) was investigated in HepG2 cells using SCGE. Additionally, the influence of ethanol on the modulation of AA-induced DNA-migration caused by CYP2E1-upregulation and/or GSH-depletion was examined in the same cell line. For the ethanol/AA combination assays, the cells were treated with ethanol for 24 h prior to exposure to 5 mM AA for another 24 h. 1.25 to 10 mM AA-induced DNA migration (OTM) in HepG2 cells in a concentration-dependent manner, e.g., exposure to 10 mM AA, resulted in an 8-fold increase of DNA migration compared to the negative control. Treatment with 120 mM ethanol prior to exposure to 5 mM AA increased the level of DNA migration more than 2-fold as compared to cells treated with 5 mM AA alone. Immunoblotting showed a clear ethanol-induced increase of CYP2E1, which plays a pivotal role in AA toxification. Additionally, intracellular GSH levels were significantly reduced after ethanol or AA treatment. In the ethanol/AA combination experiments, GSH depletion was comparable to the additive effect of the single compounds. No induction of apoptosis (ssDNA assay), but necrosis was identified as responsible for the reduction of viability with increasing compound concentration. The data clearly show a higher genotoxic potential of ethanol/AA combination treatment compared to AA treatment alone. In conclusion, both the ethanol-mediated induction of CYP2E1 and the depletion of GSH provide a mechanistic explanation for the over-additive effects of ethanol and AA. Even though the concentrations used in this study were rather high, consequences for the dietary intake of AA-containing food and alcoholic beverages should be discussed.     

运用单细胞凝胶电泳研究稀土元素钬对小鼠骨髓细胞DNA的损伤

背景与目的:探讨稀土元素钬对小鼠骨髓细胞DNA的损伤.材料与方法:给小鼠灌胃氧化钬的盐酸溶液,24h后取股骨骨髓细胞进行单细胞凝胶电泳,观察有无染色体损伤和DNA损伤.结果:试验表明在20～80 mg/kg剂量范围内,彗星细胞的尾长随剂量的增加而增长,而头长则随剂量的递增而缩短,并且在40～80 mg/kg剂量范围内与阴性组差异存在显著性;同时,拖尾率与DNA损伤率也随剂量的增加而升高.结论:稀土元素钬对小鼠骨髓细胞DNA具有一定的损伤作用.     

3种临床常用烤瓷合金对小鼠成纤维细胞L929的毒性评价

目的:评价3种临床常用牙科烤瓷合金材料的细胞毒性.方法:采用一种能快速评定细胞增殖率和细胞毒性的CCK-8比色法,检测镍铬合金(Ni,77.36%)、钴铬合金(Co,61.0%)、金合金(Au,58.0%)等3种烤瓷合金材料对小鼠成纤维细胞L929相对增殖率的影响;应用单细胞凝胶电泳(彗星电泳),检测3种烤瓷合金材料对小鼠成纤维细胞L929 DNA的损伤情况.采用SAS9.0软件包对数据进行统计学分析.结果:镍铬合金组、钴铬合金组和金合金组细胞的相对增殖率分别为(75.9510±7.6244)%、(84.8920±8.2660)%和(88.5420±12.3611)%.镍铬合金组的细胞毒性显著高于钴铬合金组(P＜0.05)和金合金组(P＜0.05),而钴铬合金组与金合金组之间无显著差异(P＞0.05),但3种材料的细胞毒性分级均为1级,表现为轻微毒性;镍铬合金组DNA损伤程度的彗星数目显著高于钴铬合金组(P＜0.05)和金合金组(P＜0.05).而钴铬合金组与金合金组无显著差异(P＞0.05).结论:钴铬烤瓷合金材料的细胞毒性显著低于镍铬烤瓷合金材料,而与58%金烤瓷合金材料的细胞毒性接近.临床上应尽可能选择钴铬烤瓷合金或58%金烤瓷合金等细胞毒性较低的烤瓷合金材料.     

低浓度氢醌的细胞毒性及DNA损伤作用

目的了解氢醌(HQ)细胞毒性及DNA损伤作用,探讨HQ遗传毒作用的机制。方法用噻唑蓝(MTT)法检测低浓度HQ对中国仓鼠肺成纤维细胞(V79细胞)作用2 h后,细胞的增殖抑制作用;用单细胞凝胶电泳技术(SCGE)检测不同浓度HQ处理V79细胞2 h后DNA的损伤情况,并观察修复2 h和4 h后彗星图像的变化。结果HQ对V79细胞生长产生明显抑制作用,并呈剂量反应关系。单细胞凝胶电泳结果显示,在设置的5个浓度范围内,彗星细胞拖尾率随着浓度的增加而增加,且有统计学意义(P<0.01);在0.405 mmol/L浓度组,尾长、Olive尾矩、彗星矩和尾/头长4个彗星损伤形态学指标随着修复时间的延长而逐渐降低,其差异有统计学意义(P<0.01)。结论在体外培养条件下,低浓度HQ能明显抑制V79细胞的增殖并呈浓度依赖关系,并能引起DNA损伤,主要是单链断裂,这种损伤部分可自身修复。     

电离辐射对作业人群外周血淋巴细胞DNA的损伤

目的　分别利用单细胞凝胶电泳技术 (SCGE)及染色体畸变试验观察电离辐射对作业人群外周血淋巴细胞DNA损伤作用和染色体损伤效应。方法　观察不同辐射剂量下外周血淋巴细胞DNA迁移长度及迁移率 ,同时观察不同剂量组下染色体畸变率及微核率。结果　各组染色体畸变率及微核率差异没有显著性 (P >0 0 5 ) ;接触射线的作业人群 ,彗星细胞率及DNA迁移长度明显超过对照组 ;同时 ,随着辐射剂量的加大 ,细胞DNA损伤级别亦有加重趋势。结论　SCGE技术可以检测电离辐射对作业人群的早期损害。     

Cytotoxic and genotoxic effects of megazol,an anti-Chagas' disease drug,assessed by different short-term tests

Cyto- and genotoxicity induced by drugs can limit the dose and duration of treatment, can adversely affect patient quality of life, and may be life-threatening. Two drugs are currently being used for treatment of the acute phase of Chagas' disease and both have serious undesirable effects. In this research, cyto- and genotoxic activity of the nitroimidazole-tiadiazole derivative CL 64855 2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole (megazol), a promising alternative drug, was evaluated in vitro with different short-term tests: (a) induction of recombination events and mutation in the yeast Saccharomyces cerevisiae D7 strain, with and without induction of cytochrome P-450; DNA damage (single and double strand breaks, alkali-labile sites, etc.) by the Comet assay in different mammalian cells. S. cerevisiae did not show a significant increase of mutant and recombinant event frequency, both with and without cytochrome P-450. On the other hand, the cytochrome complex appeared to detoxify the drug with respect to cytotoxicity. Results in rat and mouse fresh leukocytes showed a dose-response relation of drug-induced DNA damage. Findings in treated VERO cells suggested a complex treatment time-DNA damage relationship and the possible induction of repair mechanisms. Furthermore, bleomycin effects were increased in rat cells by simultaneous administration of megazol. Megazol shows different biological activity in relation to cellular types and experimental conditions (with or without cytochrome P-450, short/long time of exposure, with or without other genotoxins), thus suggesting a modulation of effectiveness by different physiological/biochemical conditions of cells. The findings could be useful to evaluate new megazol-derived compounds and to assess the risks/benefits relationship for each drug.     

氯化镉和氯化锌对V79细胞凋亡的影响

目的通过体外实验，以两种简便方法了解氯化镉（CdCl2）、氯化锌（ZnCl2）对中国仓鼠肺成纤维细胞（V79）细胞凋亡的影响。方法采用MTT法了解CdCl2对于V79细胞的毒性；在此基础上采用碱性单细胞凝胶电泳法和激光共聚焦技术结合AO／EB双染法。研究不同剂量CdCl2对V79细胞凋亡的影响，并采用生理浓度的ZnCl2与CdCl2同时作用后观察细胞凋亡情况。结果MTT实验中．CdCl2对于V79细胞的毒性随染毒剂量增加而增强。呈线性关系；碱性单细胞凝胶电泳法和AO／EB双染法得到相似的结果，即1～32μmol／LCdCl2可以引起V79细胞凋亡。凋亡率、凋亡指数分别为3．0％～49．6％及3．5％～53．8％，且随剂量增加而增大。呈剂量一效应关系；凋亡率、凋亡指数与CdCl2染毒浓度间可拟合成直线方程：y=0．9315x-0．4152。10μmol／LZnCl2可以拮抗CdCl2所致的凋亡效应。结论在本实验条件下。采用单细胞凝胶电泳和激光共聚焦技术均可以灵敏、快捷地检测CdCl2对于V79细胞的凋亡作用和锌对镉所致细胞凋亡的拮抗效应。     

铅对妊娠期及新生期大鼠神经细胞DNA的损伤

目的研究妊娠期及新生期母体铅暴露对新生仔鼠神经细胞DNA损伤作用,以进一步揭示铅的神经毒性作用机制。方法SD孕鼠随机分为6组,妊娠第1d至新生仔鼠出生后第28d进行醋酸铅[Pb(CH3COOH)2]0,50,80,120,200mg/(kg·bw)连续经口灌胃染毒。取出生8d的新生仔鼠的海马和皮层细胞,进行单细胞分离后,采用单细胞凝胶电泳(彗星试验)检测细胞,观察DNA迁移长度及拖尾细胞百分率。结果各剂量醋酸铅均可引起神经细胞DNA的单链断裂,出现彗星拖尾,其拖尾细胞百分率DNA迁移长度均随醋酸铅剂量的增加而增长,各剂量与阴性对照的结果比较均差异有统计学意义(P<0.05)。结论醋酸铅可引起神经细胞DNA损伤,并与剂量呈正相关;单细胞凝胶电泳是检测神经细胞遗传毒性及细胞凋亡的有效方法。