基于体外Pig-a基因突变试验的大黄素型蒽醌致突变风险评价

目的 对相同母核结构的8种大黄素型蒽醌类化合物开展体外Pig-a基因突变试验，分析不同大黄素型蒽醌结构与致突变性的关联。方法 L1578Y细胞分别与系列浓度的大黄素、芦荟大黄素、大黄素甲醚、大黄酚、大黄酸、羟基大黄素、大黄素-8-O-β-D-葡萄糖苷和芦荟大黄素-8-O-β-D-葡萄糖苷作用4 h（有S9）或24 h（无S9），给药24 h后应用细胞计数板进行计数，计算细胞相对倍增速率（RPD）评价受试物细胞毒性；细胞表达8 d后经APC-anti-CD45和PE-anti-CD90.2标定后，使用流式细胞仪检测突变细胞（CD45^＋CD90^－）发生率。结果 所有受试物在有或无S9代谢活化条件下所设浓度组RPD均大于50%，未见明显细胞毒性作用，可排除试验中假阳性结果。在非S9代谢活化条件下芦荟大黄素25 μg·mL^-1组Pig-a基因突变率与溶媒对照组比较显著升高（P<0.001）； S9代谢活化条件下，与溶剂对照组比较，大黄素50 μg·mL^-1组，羟基大黄素6.25、12.5、25 μg·mL^-1组，大黄酚25、50、100 μg·mL^-1组和大黄酸12.5、25、50 μg·mL^-1组Pig-a基因突变率显著升高（P<0.05、0.01、0.001）。结论 羟基取代基的多寡及所在位点是蒽醌类化合物致突变性强弱的决定性因素，其体内致突变性及致癌性作用仍需进行大量体内研究证实。     

HPLC测定肾炎宁片中大黄酸、大黄素、大黄酚及雷公藤甲素的含量

目的 建立HPLC测定肾炎宁片中大黄酸、大黄素、大黄酚及雷公藤甲素的含量。方法 大黄酸、大黄素、大黄酚的测定采用流动相为甲醇-0.1%磷酸（70∶30）,检测波长为254 nm;雷公藤甲素采用流动相为乙腈-水（25∶75）,检测波长为220 nm;两者均采用Lichrospher-C₁₈柱（4.6 mm×250 mm,5 mm）,流速均为1.0 ml·min^-1。结果 大黄酸、大黄素、大黄酚以及雷公藤甲素分别在1.83~14.64 μg·ml^-1（r=0.999 9）,2.895~23.16 μg·ml^-1（r=0.999 8）,7.625~61.00 μg·ml^-1 （r=0.999 8）以及1.52~24.32 μg·ml^-1（r=0.999 6）内与峰面积呈良好的线性关系,大黄酸平均回收率为103.2%,RSD=1.73% （n=9）;大黄素平均回收率为98.6%,RSD=3.94%（n=9）;大黄酚平均回收率为98.3%,RSD=2.54%（n=9）;雷公藤甲素平均回收率为99.61%,RSD=2.83%（n=9）。结论 本方法准确、可靠、专属性强,可作为该制剂的定量控制方法。     

高效液相色谱法测定新保肾片中芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚的含量

目的 建立新保肾片中芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚的含量测定方法,为生产质量提供保障。方法 采用高效液相色谱法测定,色谱柱为Lichrospher-C₁₈柱(250 mm ×4.6 mm,5 μm),流动相为甲醇:0.1%磷酸溶液(7030),流速为1.0 ml/min,柱温为35 ℃,检测波长为254 nm。结果 芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚分别在2.30~18.4 μg/ml(r=1.0)、2.930~23.44 μg/ml(r=1.0)、5.00~40.0 μg/ml(r=1.0)、14.870~118.96 μg/ml (r=0.999 8)、7.410~59.28 μg/ml(r=0.999 9)范围内有良好的线性关系,平均回收率分别为100.16%、102.91%、99.76%、100.32%、100.44%,RSD分别为1.58%、1.27%、1.67%、1.33%、1.03%(n=9)。结论 该方法准确易行,便于质量控制。     

HPLC法测定柔肝降脂胶囊中橙黄决明素、芦荟大黄素、大黄酚和大黄素甲醚

目的 建立柔肝降脂胶囊中橙黄决明素、芦荟大黄素、大黄酚和大黄素甲醚的HPLC测定方法。方法 采用Waters Symmetry C₁₈色谱柱（250 mm×4.6 mm,5 μm）;流动相为甲醇–0.1%磷酸水溶液,梯度洗脱;检测波长288 nm;体积流量为1.0 mL/min;柱温30℃;进样量10 μL。结果 橙黄决明素、芦荟大黄素、大黄酚、大黄素甲醚的线性范围分别为1.59～51.00、0.87～27.92、1.63～52.17、0.22～7.06 μg/mL。平均回收率分别为97.55%、100.40%、98.75%、101.30%,RSD值分别为1.93%、1.53%、1.77%、2.23%。4种蒽醌类成分中橙黄决明素和大黄酚的质量分数较高,大黄素甲醚的质量分数较低,不同批次柔肝降脂胶囊样品中芦荟大黄素的质量分数差异较明显。结论 所建立的方法可用于柔肝降脂胶囊中4种蒽醌类成分的测定,可为柔肝降脂胶囊的质量控制研究提供参考。     

基于网络药理学与分子对接技术探讨大黄肝毒性的作用机制

目的 利用网络药理学和分子对接技术探讨大黄肝毒性的分子作用机制。方法 在TCMSP检索大黄活性成分及文献获取潜在肝毒性成分，利用Swiss Target Prediction数据库获取成分靶点，通过GeneCards和OMIM数据库获取人类肝毒性相关靶点。利用STRING数据库将Venn图获得成分与疾病共同靶标进行（PPI）网络分析，用Cytoscape软件构建“大黄成分–肝毒性作用靶点”网络，并且利用DAVID数据库进行基因本体（GO）功能富集和京都基因与基因组百科全书（KEGG）（KEGG）通路富集。将部分肝毒性核心成分和关键靶点进行分子对接。结果 共获取大黄潜在肝毒性成分21种，对应靶点724个，人类肝毒性相关靶点957个，大黄与肝毒性的共同靶点151个，核心成分可能是大黄酸、大黄酚、β-谷甾醇、大黄素-1-O-β-D-葡萄糖硫苷、大黄素甲醚二葡萄糖苷、芦荟大黄素等，关键靶点可能是白蛋白（ALB）、蛋白激酶B1（Akt1）、肿瘤蛋白p53（TP53）等。KEGG通路显示癌症通路、前列腺癌通路等可能在大黄肝毒性中起关键作用。分子对接结果表明，大黄肝毒性核心成分与关键靶点对接良好。结论 大黄通过多成分、多靶点、多通路机制导致肝毒性作用。     

HPLC波长切换法同时测定茵栀祛黄胶囊中7种成分的含量

摘 要 目的：建立HPLC波长切换法同时测定茵栀祛黄胶囊中栀子苷、甘草苷、芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚的含量。方法: 采用Waters Sunfire C18（250 mm×4.6 mm,5 μm）色谱柱;流动相：甲醇（A） 0.05%磷酸溶液（B）（梯度洗脱）,流速为1.0 ml·min^-1 ,柱温为25℃,检测波长(0~15 min：在238 nm波长下检测栀子苷和甘草苷;15~50 min：在254 nm波长下检测芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚),进样量为10 μl。结果: 栀子苷、甘草苷、芦荟大黄素、大黄酸、大黄素、大黄酚和大黄素甲醚的线性范围分别为0.13～3.18 μg·ml^-1（r=0.999 8）、0.19～4.84 μg·ml^-1（r=0.999 7）、0.28～7.02 μg·ml^-1（r=0.999 9）、0.13～3.16 μg·ml^-1（r=0.999 9）、0.61～15.27 μg·ml^-1（r=0.999 9）、0.32～8.03 μg·ml^-1（r=0.999 9）、0.39～9.81 μg·ml^-1（r=0.999 9）;平均加样回收率分别为98.84%（RSD=0.74%）、99.34%（RSD=0.86%）、99.54%（RSD=0.30%）、99.56%（RSD=0.80%）、99.85%（RSD=0.41%）、99.57%（RSD=0.70%）、99.64%（RSD=0.30%）（n=9）。结论: 本文建立的HPLC含量测定方法,具有操作简便、专属性高、重复性良好、结果准确可靠的特点,可用于茵栀祛黄胶囊的质量控制。     

UHPLC-FLD法测定不同产地大黄中6种大黄蒽醌

目的 建立超高效液相色谱荧光（UHPLC-FLD）法同时测定大黄中大黄素、芦荟大黄素、大黄酸、大黄酚、大黄素甲醚和大黄素-8-O-β-D-葡萄糖苷的含量,并应用于10个不同产地大黄饮片的分析。方法 大黄粉末经甲醇提取制备供试品溶液,采用Agilent Poroshell 120 EC-C₁₈柱（50 mm×4.6 mm,2.7 μm）;流动相为0.1%甲酸水溶液（A）-0.1%甲酸甲醇（B）,梯度洗脱;体积流量0.6 mL·min^-1;柱温30℃;荧光检测器激发波长435 nm,发射波长515 nm。进行专属性、线性关系、定量限及检出限、精密度、稳定性、重复性、加样回收率考察。应用已建立的方法分析10个不同产地大黄饮片中6种大黄蒽醌含量。结果 6种成分在各自范围内线性关系良好,精密度、稳定性、重复性均良好;平均加样回收率为97.86%～103.2%,RSD为1.27%～2.15%。10个不同产地大黄饮片中蒽醌总量均符合《中国药典》要求;但不同产地的大黄中蒽醌单体的含量差别较大。结论 建立的UHPLC-FLD法灵敏、快速、准确、稳定且重复性好,可用于大黄中6种大黄蒽醌的含量测定。     

以OATP1B1/OATP1B3转运体为作用靶点的何首乌肝毒性成分筛选

目的 建立以有机阴离子转运多肽1B1（OATP1B1）和OATP1B3为作用靶点的何首乌肝毒性成分快速筛选方法。方法 使用Discovery Studio 2.5软件将何首乌主要单体成分（48个）与OATP1B1/OATP1B3蛋白进行分子对接,以OATP1B1和OATP1B3主要转运底物胆红素作为阳性对照,对目标化合物进行虚拟筛选;采用CCK-8法考察芦荟大黄素-8-O-β-D-葡萄糖苷（AEG）、大黄素-8-O-β-D-葡萄糖苷（EG）、大黄素甲醚-8-O-β-D-葡萄糖苷（PG）、2,3,5,4''-四羟基二苯乙烯-2-O-β-D-葡萄糖苷（TSG）处理24 h后对人源肝永生化肝细胞HepaRG的毒性强弱,并采用实时荧光定量PCR （qRT-PCR）技术测定4种化合物对HepaRG细胞的OATP1B1和OATP1B3 mRNA表达量的影响。结果 与OATP1B1对接结果显示,polygonumnolide B3、cis-emodin-physcionbianthrones、polygonumnolide B2、大黄素甲醚-8-β-D-（6''-O-乙酰基）-葡萄糖苷、trans-emodin-physcionbianthrones、大黄素-3-甲醚-8-O-β-D-葡萄糖苷、polygonumnolide B4、大黄酚-8-O-葡萄糖苷、EG、大黄素-1-O-β-D-葡萄糖苷、AEG、大黄酚-8-O-β-D-葡萄糖苷、大黄酸-8-O-葡萄糖苷高于胆红素打分值的80%,可被初步认定为潜在毒性成分;与OATP1B3对接结果显示,trans-emodin-physcionbianthrones、PG、polygonumnolide A4及虎杖苷高于胆红素打分值的80%,可被初步认定为潜在毒性成分。CCK-8实验进一步证实AEG、EG及PG均具肝细胞毒性作用,半数抑制浓度分别为16.10、49.43、69.44 μg·mL^-1,与分子对接结果一致。与对照组比较,AEG、EG均可显著下调OATP1B1的mRNA表达水平（P<0.05）;PG可显著下调OATP1B3的mRNA表达水平（P<0.05）。结论 以OATP1B1/OATP1B3分子对接技术为切入点,可有效预测何首乌潜在肝毒性成分,实现快速高效的高通量筛选,为中药安全性评价提供新思路。     

Ames波动试验和GADD45a-GFP GreenScreen两种快速筛选方法评价大黄素和芫花素的遗传毒性

目的 使用Ames波动试验和GADD45a-GFP GreenScreen两种快速筛选方法,对有毒中药芫花和了哥王的主要单体成分大黄素和芫花素的遗传毒性进行评价。方法 （1）Ames波动试验：在非代谢活化（-S9）和代谢活化（+S9）条件下使用鼠伤寒沙门菌TA100开展基于96孔液态培养法的细菌回复性突变试验,大黄素和芫花素（终质量浓度范围均为0.1~10 μg/mL）与菌液充分混合后在37℃下培养72 h。（2）GADD45a GreenScreen高通量筛选试验：在非代谢活化（-S9）和代谢活化条件下（+S9）将表达GADD45a基因的TK细胞（GenM-T01和GenM-C01）与大黄素（0.13~32.0 μg/mL）和芫花素（0.07~16.0 μg/mL）分别作用48 h（-S9）和3 h（+S9）,之后通过酶标仪和流式细胞仪检测绿色荧光蛋白（enhanced green fluorescent protein,EGFP）的荧光强度。结果 有无代谢活化条件下,10 μg/mL大黄素均可诱导TA100的回复性突变率显著性升高（P<0.05、P<0.001）;代谢活化条件下,10 μg/mL芫花素可诱导TA100的回复性突变率显著性升高（P<0.001）,16.0 μg/mL芫花素诱导TK6细胞表达的GADD45a-EGFP荧光强度也超过了遗传毒性阈值（1.3倍）。结论 当前研究提示大黄素和芫花素为可疑遗传毒性,需要开展深入研究明确其遗传毒性及机制。Ames波动试验和GADD45a GreenScreen是良好的高通量筛选备选试验,可极大优化浩繁的药物的毒性筛选工作,尤其适宜诸如中药等成分和配伍复杂的药物。     

基于毒理学软件和细菌回复突变试验的大黄素型蒽醌基因突变风险评价

目的 使用毒理学软件和细菌回复突变（Ames）试验评价大黄素型蒽醌类化合物的致突变风险，分析不同取代基及所在位置对大黄素型蒽醌致突变风险的影响。方法 使用Toxtree、Derek Nexus和Sarah Nexus毒性预测软件对大黄素、羟基大黄素、芦荟大黄素、大黄素甲醚、大黄酚、大黄酸、大黄素-8-O-β-D-葡萄糖苷、芦荟大黄素-8-O-β-D-葡萄糖苷、大黄素-1-O-β-D-葡萄糖苷、大黄素甲醚-8-O-β-D-葡萄糖苷的致突变风险进行预测，并使用鼠伤寒沙门氏菌TA97、TA98、TA100、TA102、TA1535和TA1537及大肠杆菌WP2 uvrA开展基于6孔板的Ames试验，评价10种大黄素型蒽醌的致突变性。结果 基于蒽醌母核结构，Toxtree、Derek Nexus和Sarah Nexus毒性预测软件提示所有大黄素型蒽醌均存在致突变风险。在非S9代谢活化状态下，芦荟大黄素导致TA98和WP2 uvrA Ames菌落数增加，大黄酚、大黄酸导致WP2 uvrA Ames菌落数增加。在大鼠肝S9代谢活化状态下，大黄素和大黄酸导致TA98和TA1537 Ames菌落数增加，羟基大黄素导致TA97、TA98、TA1537和WP2 uvrA Ames菌落数增加，芦荟大黄素导致TA98、TA1537和WP2 uvrA Ames菌落数增加，大黄素甲醚导致TA1537 Ames菌落数增加，大黄酚导致TA1537和WP2 uvrA回复菌落突变数增加，大黄素-8-O-β-D-葡萄糖苷可引起TA1537回复突变菌落数增加。结论 大黄素型蒽醌类化合物在大黄素母核的基础引入羟基后其诱变能力显著升高，较大葡萄糖苷基团的引入反而使受试物诱变能力降低。     

Evaluation of oxidative damage and inhibition of DNA repair in an in vitro study of nickel exposure

It has been suggested that Nickel is involved in oxidative damage and inhibition of DNA repair. We studied the effects of NiSO₄ on oxidative stress and DNA repair in Jurkat cells to elucidate its mechanism of action. Cells were treated with H₂O₂ and ROS generation (by flow cytometry), and oxidative DNA damage (as tail moment by Fpg-enzyme comet test), were evaluated immediately and after 4 and 24 h of DNA damage recovery occurred in presence or absence of NiSO₄ (0.017 and 0.17 μ ) to clarify possible interactions of Ni with DNA repair processes. Moreover, cells were exposed to the same doses of NiSO₄ for 4 and 24 hours to evaluate its direct oxidative effect. The results of the comet test showed high tail moment immediately after oxidative burst with a decreasing after 4 h of DNA recovery, and a slight increase after 24 h of recovery. The decreases were more limited for cells treated with NiSO₄ 0.17 μ indicating an inhibition of oxidative DNA damage repair by this substance. An induction of ROS was observed after 4 h of incubation with higher dose of NiSO₄. Cells treated with H₂O₂ showed the highest level of ROS after 4 h of recovery in presence of NiSO₄ 0.17 μ that remained at elevated levels also after 24 h of recovery suggesting a synergistic action of Ni with H₂O₂ in the reduction of cellular anti-oxidative defence activities.     

Isogoniotriol衍生物对肿瘤细胞DNA的损伤

目的:研究Isogoniotriol衍生物对肿瘤细胞DNA的损伤作用。方法:用Isogoniotriol衍生物处理体外培养白血病K562细胞,MTT法测定IC50,应用单细胞凝胶电泳(SCGE)检测细胞核DNA的损伤。结果:Isogoniotriol衍生物处理K562细胞IC50为4×10-5mol/L,不同浓度的Isogoniotriol衍生物处理细胞后可见彗星状拖尾。结论:Isogoniotriol衍生物可造成肿瘤细胞DNA损伤,抑制肿瘤细胞生长。     

铅对小鼠睾丸细胞DNA损伤作用研究

目的:通过建立亚慢性铅中毒动物模型探讨醋酸铅对雄性小鼠睾丸细胞DNA的损伤,为进一步了解其毒性作用机制提供科学依据。方法:将45只雄性小鼠分为0.2%、0.4%染铅组及空白对照组,每组各5只。实验组醋酸铅溶于去离子水中供小鼠自由摄取,空白对照组饮用自来水。分别于第2、4、6周分别处死动物,用单细胞凝胶电泳实验(彗星实验)检测小鼠睾丸细胞DNA损伤情况。结果:醋酸铅染毒后小鼠睾丸细胞DNA单链断裂,出现彗星状拖尾。无论是拖尾细胞的百分率,DNA迁移的长度,还是olive尾矩与空白对照组相比其差异具有极显著性(P<0.01),并且随着醋酸铅染毒浓度和时间的增加DNA的损伤越重,呈现出时间-效应关系。但0.2%与0.4%各周染毒组的拖尾细胞百分率、彗星尾长、olive尾矩的差异并无显著性(P>0.05)。结论:醋酸铅可诱导睾丸生殖细胞DNA损伤,并且其损伤作用呈现出时间依赖性。     

蕃茄汁对人前列腺癌PC-3细胞增殖的影响

目的　研究番茄汁对人前列腺癌PC 3细胞增殖的影响及其可能的机制。方法　体外培养人前列腺癌PC 3细胞,分别加入不同浓度的番茄汁;用彗星试验测定经番茄汁处理的人前列腺癌PC 3细胞DNA链断裂情况,分析DNA的损伤作用;采用MTT法测定细胞的增殖情况。结果　番茄汁对人前列腺癌PC 3细胞的DNA具有损伤作用,可使DNA链断裂,DNA的迁移长度与彗星细胞拖尾率显著增高,与对照组相比,差异有非常显著性;能抑制PC 3细胞的增殖,与对照组相比,各实验组的吸光度逐渐降低,差异有非常显著性,且随着浓度的增加抑制作用逐渐加强。结论　番茄汁可诱导人前列腺癌PC 3细胞的DNA损伤,从而抑制其生长。     

Genotoxicity of marine sediments in the fish hepatoma cell line PLHC-1 as assessed by the Comet assay

The main goal of this study was to test the usefulness of the Comet assay in the PLHC-1 hepatoma fish cell line as a tool for detecting the presence of genotoxic compounds in contaminated marine sediments. The system has been tested using both model chemicals (benzo[a]pyrene (B[a]P) and ethyl methanesulfonate (EMS)) and extracts of sediment samples obtained with solvent dichloromethane/methanol. For all of the analysed sediment extracts as well as for the model chemicals a concentration dependent genotoxic effect was observed. The sediment with the highest observed genotoxic potential was additionally extracted using various solvents in order to test which class of compounds, according to their polarity, is most responsible for the observed genotoxic effect. Non-polar solvents (cyclohexane and dichloromethane) yielded stronger genotoxic effect but the highest level of DNA damage was determined after exposure to sediment extract obtained with the solvent mixture dichloromethane/methanol which extracts a wide range of contaminants. Our results indicate that the PLHC-1 cell line is a suitable in vitro model in sediment genotoxicity assessment and encourage the use of fish cell lines as versatile tools in ecogenotoxicology.     

Evaluating the combinative effects on human lymphocyte DNA damage induced by ultraviolet ray C plus 1.8 GHz microwaves using comet assay in vitro

The objective of this study was to observe whether 1.8 GHz microwaves (MW) (SAR, 3 W/kg) exposure can influence human lymphocyte DNA damage induced by ultraviolet ray C (UVC). The lymphocytes, which were from three young healthy donors, were exposed to 254 nm UVC at the doses of 0.25, 0.5, 0.75, 1.0, 1.5 and 2.0 J m(-2), respectively. The lymphocytes were irradiated by 1.8 GHz MW (SAR, 3 W/kg) for 0, 1.5 and 4 h. The combinative exposure of UVC plus MW was conducted. The treated cells were incubated for 0, 1.5 and 4 h. Finally, comet assay was used to measure DNA damage of above treated lymphocytes. The results indicated that the difference of DNA damage induced between MW group and control group was not significant (P>0.05). The MTLs induced by UVC were 1.71+/-0.09, 2.02+/-0.08, 2.27+/-0.17, 2.27+/-0.06, 2.25+/-0.12, 2.24+/-0.11 microm, respectively, which were significantly higher than that (0.96+/-0.05 microm) of control (P<0.01). MTLs of some sub-groups in combinative exposure groups at 1.5-h incubation were significantly lower that those of corresponding UVC sub-groups (P<0.01 or P<0.05). However, MTLs of some sub-groups in combinative exposure groups at 4-h incubation were significantly higher that those of corresponding UVC sub-groups (P<0.01 or P<0.05). In this experiment it was found that 1.8 GHz (SAR, 3 W/kg) MW exposure for 1.5 and 4 h did not enhance significantly human lymphocyte DNA damage, but could reduce and increase DNA damage of human lymphocytes induced by UVC at 1.5-h and 4-h incubation, respectively.     

Genotoxicity evaluation of locally produced dental porcelain – An in vitro study using the Ames and Comet assays

The aim of this study was to determine the genotoxicity of a locally produced dental porcelain (Universiti Sains Malaysia, Malaysia) using the Ames and Comet assays. In the Ames assay, four genotypic variants of the Salmonella strains (TA98, TA100, TA1537 and TA1535) carrying mutations in several genes were used. The dental porcelain was incubated with these four strains in five different doses both in the presence and absence of metabolic activation (S9) and the result was assessed based on the number of revertant colonies. Concurrently, appropriate positive controls were used so as to validate the test. The average number of revertant colonies per plate treated with locally produced dental porcelain was less than double as compared to that of negative control. In the Comet assay, L929 (CCL-1 ATCC, USA) mouse fibroblast cells were treated with the dental porcelain in three different concentrations along with concurrent negative and positive controls. The tail moment which was used as a measurement of DNA damage was almost equal to that of the negative control, suggesting that the locally produced dental porcelain did not induce any DNA damage. The results indicated that the locally produced dental porcelain is non-genotoxic under the present test conditions.     

The assessment of genotoxic effects of wastewater from a fertilizer factory

In this study we investigated cytotoxic, mutagenic and genotoxic effects of different concentrations of wastewater from the phosphoric gypsum depot near the factory for fertilizing agents 'INA Petrokemija' (Kutina, Croatia). The Ames test was performed on Salmonella typhimurium TA98 and TA100 strains, in the presence of S9 mix, glutathione and buffer, respectively. Cytotoxicity was studied on human laryngeal carcinoma cells (HEp2) and human cervical cells (HeLa). The level of lipid peroxidation in these two cell lines was evaluated in parallel. To establish the levels of primary DNA damage, the alkaline comet assay was performed on treated human peripheral blood leukocytes. No mutagenic effects of phosphoric gypsum on Salmonella typhimurium strains in the presence of S9 mix, GSH or PBS were observed. However, strong cytotoxic effect was observed on both human cell lines when they were treated with different concentrations of wastewater. Lipid peroxidation was induced and increased by prolonged time of incubation, highlighting that the damage was not repaired, but increased with the time of incubation. The results of the alkaline comet assay indicate significant DNA damaging potential of wastewater for human leukocytes. Since phosphoric gypsum transport water in its present composition and acidity is highly toxic and acts as prooxidant, causing free radicals formation and DNA damage, urgent neutralization/purification of the wastewater to a level acceptable for disposal into the environment is mandatory.     

Influence of aroclor 1254 on benzo(a)pyrene-induced DNA breakage, oxidative DNA damage, and cytochrome P4501A activity in human hepatoma cell line

Both polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs) are important environmental pollutants. They coexist widely in the environment at very low levels. Numerous studies indicated that aroclor1254 (one of PCBs mixture) is the inducer of cytochrome P450 1A enzyme acitivity. Benzo(a)pyrene (BaP) can cause a variety of toxicities in vitro, such as oxidative DNA damage and genotoxicity. In the present study, HepG2 cells were treated with either BaP (50 microM) or aroclor1254 at concentrations of 11.5 (low), 23.0 (medium), and 46.0 microM (high) alone, or pretreated the cells with aroclor1254 (11.5, 23.0, and 46.0 microM), followed by BaP (50 microM). It was found that 7-ethoxyresorufin-O-deetylase (EROD) activities of HepG2 cells exposed to either BaP or aroclor 1254 increased. DNA damage measured by DNA migration and the formation of 8-hydroxy-2'-deoxyguanosine (8-OHdG) also increased in cells exposed to BaP, but not in cells exposed to aroclor1254. Under the Aroclor 1254 pretreatment condition, BaP-induced EROD activities was enhanced in cells exposed to the medium and high concentrations of aroclor1254 (P < 0.01 for both), whereas in all pretreatment groups aroclor1254 significantly increased BaP-induced DNA migration (P < 0.01 for all) and the 8-OHdG formation (P < 0.05 for all). In addition, there was positive correlation between the EROD induction activity and Olive tail moment (r(2) = 0.958, P < 0.01) or the levels of 8-OHdG (r(2) = 0.992, P < 0.01). The findings suggest that under the experimental conditions aroclor1254 may enhance BaP-induced DNA migration and oxidative DNA damage in HepG2, due to inducing CYP1A enzyme activity.     

Exposure to 1800 MHz radiofrequency electromagnetic radiation induces oxidative DNA base damage in a mouse spermatocyte-derived cell line

Whether exposure to radiofrequency electromagnetic radiation (RF-EMR) emitted from mobile phones can induce DNA damage in male germ cells remains unclear. In this study, we conducted a 24 h intermittent exposure (5 min on and 10 min off) of a mouse spermatocyte-derived GC-2 cell line to 1800 MHz Global System for Mobile Communication (GSM) signals in GSM-Talk mode at specific absorption rates (SAR) of 1 W/kg, 2 W/kg or 4 W/kg. Subsequently, through the use of formamidopyrimidine DNA glycosylase (FPG) in a modified comet assay, we determined that the extent of DNA migration was significantly increased at a SAR of 4 W/kg. Flow cytometry analysis demonstrated that levels of the DNA adduct 8-oxoguanine (8-oxoG) were also increased at a SAR of 4 W/kg. These increases were concomitant with similar increases in the generation of reactive oxygen species (ROS); these phenomena were mitigated by co-treatment with the antioxidant α-tocopherol. However, no detectable DNA strand breakage was observed by the alkaline comet assay. Taking together, these findings may imply the novel possibility that RF-EMR with insufficient energy for the direct induction of DNA strand breaks may produce genotoxicity through oxidative DNA base damage in male germ cells.