亚硝基脲类遗传毒性杂质稳定性影响因素考察

目的 ：考察以N-甲基-N-亚硝基脲（MNU）和N-乙基-N-亚硝基脲（ENU）为代表化合物的亚硝基脲类遗传毒性杂质的稳定性及其影响因素。方法 ：采用高效液相色谱（HPLC）考察不同光照（避光、自然光、紫外光）和不同温度（室温、冷藏）条件对ENU和MNU溶液稳定性的影响;采用HPLC考察MNU和ENU在不同储存条件下的短期稳定性;采用气相色谱-质谱联用（GC-MS）考察不同进样口温度（200℃和120℃）对ENU测定准确性的影响。结果 ：MNU和ENU对光照和温度较为敏感,在光照和室温条件下,均会发生降解;MNU和ENU分别在40℃、75%湿度下放置5天和12天后降解明显;GC-MS进样口温度对ENU的检测影响较大。结论 ：建议亚硝基脲类遗传毒性杂质应在-20℃避光处保存,在检测过程中控制温度参数;在溶液配制过程中应避光操作、临用新制,以避免出现遗传毒性杂质检测假阴性结果。     

体内彗星试验在药物遗传毒性评价中的研究方法

体内彗星试验是采用单细胞凝胶电泳的方法检测体内DNA损伤的技术。具有灵敏度高、操作简便、经济快速等优点。随着遗传毒性研究的发展,体内彗星试验已经成为重要的药物遗传毒性评价方法。对动物试验阶段和彗星试验阶段各操作步骤进行了归纳总结,以期对相关方法学建立提供参考,并提出采用简化和标准化的研究方法将有利于体内彗星试验在药物遗传毒性评价的应用。     

彗星实验检测2种细胞DNA损伤方法

丙烯酰胺（acrylamide，AA）在工业上有广泛的用途，对AA的暴露研究结果均显示其有一定的神经系统毒性和致癌作用。自2002年瑞典国家食品管理局和斯德哥尔摩大学首次报道，在煎烤烹炸类食品中发现高含量AA后，其安全性引起了各国科学家的普遍关注。近年来动物实验研究表明，AA也具有一定遗传毒性和生殖毒性，为此本研究通过彗星实验检测其外周淋巴细胞和睾丸细胞的损伤，     

微核试验和彗星试验检测雄黄的遗传毒性

目的用短期给药(小鼠骨髓细胞微核试验和彗星试验)和长期给药(利用生殖毒性Ⅰ段试验的大鼠做微核试验和彗星试验)检测雄黄的遗传毒性,探讨利用长期毒性试验或生殖毒性Ⅰ段试验用动物进行遗传毒性检测的可行性。方法小鼠ig给予雄黄0.25,0.5和1.0 g·kg-1,每天1次,2 d后,取骨髓细胞做微核试验和彗星试验;利用生殖毒性Ⅰ段大鼠ig给予0.125,0.25和0.55 g·kg-1,雄性连续给药42 d以上,交配成功后处死;雌性连续ig给药19 d以上,妊娠第15天,取骨髓细胞做微核试验和彗星试验,取血做外周血淋巴细胞微核试验。结果与阴性对照组比较,小鼠雄黄0.25,0.5和1.0 g·kg-1组微核试验微核率分别为3.0‰,4.40‰,7.01‰(P<0.05,P<0.01)和彗星试验拖尾率分别为6.3%,9.7%和11.3%(P<0.05,P<0.01)。与阴性对照组比较,生殖毒性Ⅰ段试验大鼠ig给予雄黄,雄黄0.55 g·kg-1组雄性大鼠的骨髓微核和外周血淋巴细胞微核率分别为2.83‰和6.67‰(P<0.05),雌性大鼠0.25和0.55 g·kg-1的骨髓微核和外周血淋巴细胞微核率分别为1.5‰,2.25‰以及2.58‰和4.40‰(P<0.05,P<0.01);雄黄使雄性和雌性大鼠彗星拖尾率明显升高(P<0.05)。结论利用生殖毒性Ⅰ段试验多次给药后取材做微核试验和彗星试验方法可行;外周血微核试验简便易行;在所观察的剂量下雄黄具有遗传毒性。     

红景天苷注射液遗传毒性的研究

目的：检测红景天苷注射液的遗传毒性。方法：应用微生物回复突变实验（Ames实验,5 000、500、50、5.0、0.5μg/皿）、体外培养CHO细胞染色体畸变实验（2 0001、000、500μg/mL）和小鼠骨髓微核实验法（1 500、750、375μg/kg）检测红景天苷注射液的遗传毒性。结果：红景天苷注射液对鼠伤寒沙门菌无致突变性,对体外培养CHO细胞染色体无致畸变作用,对ICR小鼠无诱发骨髓嗜多染红细胞微核的效应,三个实验结果均呈阴性。结论：红景天苷注射液不具有遗传毒性。     

消旋酶法DL-丙氨酸的遗传毒性研究

目的 评价消旋酶法DL-丙氨酸的遗传毒性。方法 小鼠骨髓细胞微核实验设阴性对照组（纯水）、阳性对照组（环磷酰胺40 mg/kg）和消旋酶法DL-丙氨酸3个剂量组（10 000、5 000和2 500 mg/kg）,观察各组小鼠胸骨骨髓细胞微核发生率;小鼠精原细胞染色体畸变实验设阴性对照组（纯水）、阳性对照组（环磷酰胺40 mg/kg）和消旋酶法DL-丙氨酸3个剂量组（10 000、5 000和2 500 mg/kg）,观察各组小鼠睾丸精原细胞染色体畸变类型并计算畸变率。细菌回复突变实验（Ames实验）设空白对照组、溶剂对照组、阳性对照组和消旋酶法DL-丙氨酸5个剂量组（50、158、500、1 580、5 000 μg/皿和8、40、200、1 000、5 000 μg/皿）,计数各组回复突变菌落数。结果 小鼠骨髓细胞微核实验结果显示,各剂量组消旋酶法DL-丙氨酸微核细胞率与对照组的差异无统计学意义（P>0.05）;小鼠精原细胞染色体畸变实验结果显示,各剂量组消旋酶法DL-丙氨酸动物睾丸精原细胞染色体畸变率与对照组的差异无统计学意义（P>0.05）;细菌回复突变实验结果显示,在加或不加S9的情况下,各剂量组消旋酶法DL-丙氨酸对TA97a、TA98、TA100、TA102、TA1535菌株均无致突变作用,差异无统计学意义（P>0.05）。结论 消旋酶法DL-丙氨酸未见明显遗传毒性。     

大黄素体内遗传毒性风险评价

目的 评价连续28 d灌胃给予小鼠大黄素,小鼠体内遗传毒性风险。方法 KM小鼠连续28 d灌胃重复给予大黄素并设28 d恢复期。分别于给药前、首次给药后第14、 28、 42和56天采集外周血检测网织红细胞和总红细胞的突变率,以及网织红细胞占总红细胞的百分率;末次给药后采集肝、肾、外周血开展彗星试验,分析每只动物至少100个细胞的尾DNA百分含量;末次给药后制备骨髓细胞样本,计算嗜多染红细胞占总红细胞的百分率以及嗜多染红细胞的微核发生率。结果 与溶媒对照组（0.5%羧甲基纤维素钠）相比,300 mg·kg-1及以下给药组连续给药28 d未见Pig-a基因突变率增加。肾细胞彗星试验结果显示,与溶媒对照组（0.5%羧甲基纤维素钠）相比,所设浓度范围内各组尾DNA百分含量显著升高（P<0.01,P<0.001）。骨髓微核试验显示所设浓度范围内未见微核率的升高。结论 连续28 d经口灌胃给予小鼠大黄素后,主要作用部位为肾脏;当前试验条件下,大黄素未导致小鼠体内Pig-a基因突变发生率和骨髓微核发生率增加,但可导致肾脏细胞DNA损伤。     

大鼠肝彗星试验与骨髓微核试验评价结果比较研究

目的 梳理国家药物安全评价监测中心联合开展的大鼠多终点体内遗传毒性试验数据,比较大鼠肝彗星试验与骨髓微核试验结果的一致性和灵敏性。方法 试验分设阴性物质组、作用机制明确的遗传毒性阳性物质组、受试物组,阴性物质包括超纯水、0.9%氯化钠注射液、玉米油、0.5%羧甲基纤维素钠（CMC-Na）、5%蔗糖和聚山梨酯80,给药体积为10 mL·kg^-1;遗传毒性阳性物质包括200 mg·kg^-1甲磺酸乙酯（EMS）、40 mg·kg^-1N-乙基-N-亚硝基脲（ENU）、40 mg·kg^-1环磷酰胺、75 mg·kg^-1甲基苄肼、800 mg·kg^-1尿烷、75 mg·kg^-1对氯苯胺、40 mg·kg^-1 1,2-二溴-3-氯丙烷和10 mg·kg^-1秋水仙素;受试物包括100、300、1000 mg·kg^-1大黄素-8-O-β-D-葡萄糖苷,6.5、65.0、650.0 mg·kg^-1单蒽酮和6.5、65.0、650.0 mg·kg^-1大黄素甲醚。分别在实验0、24、45 hig给药1次,给药体积为10 mL·kg^-1。开展大鼠肝彗星试验和骨髓微核试验,计算每只动物的肝细胞刺猬细胞率和尾DNA百分含量（Tail% DNA）,以及每只动物的嗜多染红细胞（PCE）/总红细胞（ERY）比例和嗜多染红细胞微核（MNPCE）率。结果 大鼠肝彗星试验可有效检出DNA断裂剂,对多种烷化剂（甲磺酸乙酯、甲基苄肼和尿烷等）有较好的预测性,但对环磷酰胺和多倍体诱导剂不灵敏。大黄素-8-O-β-D-葡萄糖苷、单蒽酮和大黄素甲醚骨髓微核试验结果均为阴性。大黄素-8-O-β-D-葡萄糖苷在1 000 mg·kg^-1剂量下导致的肝Tail% DNA与0.5% CMC-Na组比较显著升高（P<0.05）;单蒽酮的肝彗星试验结果为明确阳性,剂量为650 mg·kg^-1时,单蒽酮可导致大鼠肝Tail% DNA显著升高（P<0.05）,且作用存在剂量相关性;大黄素甲醚的肝彗星试验结果为阴性。结论 大鼠肝彗星试验可与骨髓微核试验互补,有效检出主要作用于肝脏且亲电子性较强的遗传毒性化合物。     

丹参注射液单次给药的毒性及遗传毒性研究

目的研究丹参注射液的单次给药毒性及遗传毒性,为评价其安全性提供毒理学依据。方法采用一次性给予丹参注射液,观察ICR小鼠产生的毒性反应;用体外细菌回复突变(Ames)实验、中国仓鼠肺成纤维细胞(CHL)体外染色体畸变实验、小鼠骨髓嗜多染红细胞微核实验进行丹参注射液的遗传毒性研究。结果在单次给药毒性中,5个剂量组动物死亡数分别为9,7,4,3和0只;Ames实验中,丹参注射液剂量分别为5 000,2 000,500,50和5μg·皿-1,无论加或不加哺乳动物肝脏微粒体酶(S9),各剂量组的回复突变菌落数均未出现剂量依赖性的增加,结果为阴性;在染色体畸变实验中,非活化条件或代谢活化条件下,细胞的染色体畸变率均未出现剂量依赖性增加;在微核实验中,与溶媒对照组比较,丹参注射液各剂量组中的微核率均无显著性差异。结论在本实验条件下,单次给药毒性研究中,丹参注射液小鼠静脉注射给药的LD50为68.72g·kg-1,95%可信限为66.92~70.58g·kg-1,其对小鼠的急性毒性可能靶器官组织为肺脏。遗传毒性实验结果均为阴性,即中药制剂丹参注射液无潜在的致突变性。     

光泽汀体内遗传毒性风险评价

目的 评价光泽汀小鼠体内的遗传毒性。方法 C57BL/6J小鼠分为溶剂对照（0.5% CMC-Na）组、茜草素（200 mg·kg^-1，结构对照）组、乙酰基亚硝基脲（ENU，40 mg·kg^-1，阳性对照）组、甲基磺酸乙酯（EMS，200 mg·kg^-1，阳性对照）组和光泽汀低、中、高剂量（100、200、300 mg·kg^-1）组，溶剂、光泽汀和茜草素连续7 d ig给予，给药第1天记为D1，阳性对照ENU和EMS分别连续3 d给予，均每天给药1次。于D7、D56采集约0.5 mL外周血用于血清生化检测；于D14、D28、D42、D56采集外周血开展Pig-a基因突变试验；末次给药后采集肝、肾细胞开展彗星试验，分析每只动物至少100个细胞的尾DNA百分含量；末次给药后制备骨髓细胞样本，计算嗜多染红细胞的微核发生率。解剖后取心、肝、脾、肺以及肾脏进行组织病理学检查。结果 试验期间所有动物一般症状未见明显异常，各组动物体质量未见明显差异，未见与给予受试物有关的组织病理学改变。光泽汀低、中、高剂量组及EMS组肾脏尾DNA百分率均显著高于溶剂对照组（P<0.05、0.001），光泽汀高剂量组及EMS组肝脏尾DNA百分率与溶剂对照组比较显著增加（P<0.05、0.001）。光泽汀与茜草素的小鼠骨髓微核试验、Pig-a基因突变试验均为阴性。结论 100～300 mg·kg^-1光泽汀未见对小鼠整体产生明显毒性。光泽汀可导致小鼠肝、肾细胞DNA损伤，肾细胞DNA损伤程度更为严重。     

In Vivo Micronucleus Assay and GST Activity in Assessing Genotoxicity of Plumbagin in Swiss Albino Mice

Information available on the mutagenicity of a large number of indigenous drugs commonly employed in the Siddha and Ayurveda systems of medicine is scanty. In this context, the current investigation on plumbagin, 5-hydroxy-2methyl-1,4-napthoquinone, an active principle in the roots of Plumbago zeylanica used in Siddha and Ayurveda for various ailments, was carried out; 16 mg/kg b.w. (LD₅₀) was fixed as the maximum dose. Subsequent dose levels were fixed as 50% and 25% of LD₅₀ amounting to 8 mg and 4 mg/kg b.w., respectively, and given orally for 5 consecutive days in 1% Carboxyl Methyl Cellulose (CMC) to Swiss albino mice weighing 25–30 g. The micronucleus assay was done in mouse bone marrow. Plumbagin was found to induce micronuclei at all the doses studied (4 mg/kg, 8 mg/kg, 16 mg/kg b.w.), and it proves to be toxic to bone marrow cells of Swiss albino mice. Animal treated with cyclophosphamide (40 mg/kg b.w.) served as positive control. In addition, glutathione S-transferase (GST) activity was observed in control, plumbagin (4 mg, 8 mg, 16 mg/kg b.w., respectively), and genotoxin-treated experimental group of animals. No significant change in GST activity was observed with plumbagin dose of 4 mg/kg b.w., whereas GST activity was significantly inhibited by higher doses of plumbagin (8 mg and 16 mg/kg b.w.) and cyclophosphamide.     

Patulin: Mechanism of genotoxicity

Patulin is a frequently found food contaminant mainly produced by the fungi Aspergillus and Penicillium. Patulin is suspected to be clastogenic, mutagenic, teratogenic and in higher concentrations cytotoxic. Here, we investigate the mechanism of the patulin-induced genotoxicity. Chromosomal damage was detected as micronucleus and nucleoplasmic bridge formation. Due to the activity of patulin on SH-groups, glutathione is a major compound in the cellular defense against patulin and the depletion of glutathione level with buthionine sulfoximine led to a strong increase in the genoxicity of patulin. A modified version of the alkaline comet assay was carried out to show the cross-linking properties of patulin. As a mechanistic hypothesis, we suspect patulin to cause structural DNA damage by cross-linking, yielding nucleoplasmic bridges and as a later consequence, micronucleus formation. The structural DNA damage may also lead to cell cycle delays, the consequence of which may be the observed centrosome amplification and formation of multipolar mitotic spindles.     

Genotoxicity assessment of the antimalarial compound artesunate in somatic cells of mice

Artesunate is a derivate of artemisinin that is both an antimalarial agent and acts cytotoxically on tumor cells. Despite its therapeutic use, its in vivo genotoxic potential has still not been evaluated. This study, therefore, was an investigation into the effects of a single oral administration of artesunate with an in vivo comet assay that analyzed leukocytes from peripheral blood and liver cells, and a micronucleus (MN) assay of bone marrow cells from male Swiss mice. The artesunate was administered by oral gavage at doses of 5, 50 and 100 mg/kg. Cytotoxicity was assessed by scoring 200 consecutive polychromatic (PCE) and normochromatic (NCE) erythrocytes (PCE/NCE ratio). The results demonstrate that artesunate induced significant DNA damage only in liver cells and that high doses of artesunate caused an increase in the mean number of micronucleated polychromatic erythrocytes (MNPCE). Under our experimental conditions, artesunate showed weak genotoxic effects at low doses and clastogenic effects at high doses. The PCE/NCE ratio indicated no cytotoxicity. The data obtained suggest caution about either continuous or high-dose use of artesunate by humans.     

Genotoxicity evaluation of titanium dioxide nanoparticles using the Ames test and Comet assay

Titanium dioxide nanoparticles (TiO₂‐NPs) are being used increasingly for various industrial and consumer products, including cosmetics and sunscreens because of their photoactive properties. Therefore, the toxicity of TiO₂‐NPs needs to be thoroughly understood. In the present study, the genotoxicity of 10nm uncoated sphere TiO₂‐NPs with an anatase crystalline structure, which has been well characterized in a previous study, was assessed using the Salmonella reverse mutation assay (Ames test) and the single‐cell gel electrophoresis (Comet) assay. For the Ames test, Salmonella strains TA102, TA100, TA1537, TA98 and TA1535 were preincubated with eight different concentrations of the TiO₂‐NPs for 4 h at 37 °C, ranging from 0 to 4915.2 µg per plate. No mutation induction was found. Analyses with transmission electron microscopy (TEM) and energy‐dispersive X‐ray spectroscopy (EDS) showed that the TiO₂‐NPs were not able to enter the bacterial cell. For the Comet assay, TK6 cells were treated with 0–200 µg ml^–1 TiO₂‐NPs for 24 h at 37 °C to detect DNA damage. Although the TK6 cells did take up TiO₂‐NPs, no significant induction of DNA breakage or oxidative DNA damage was observed in the treated cells using the standard alkaline Comet assay and the endonuclease III (EndoIII) and human 8‐hydroxyguanine DNA‐glycosylase (hOGG1)‐modified Comet assay, respectively. These results suggest that TiO₂‐NPs are not genotoxic under the conditions of the Ames test and Comet assay. Published 2012. This article is a US Government work and is in the public domain in the USA.     

Genotoxicity assessment of propyl thiosulfinate oxide,an organosulfur compound from Allium extract,intended to food active packaging

Essential oils from onion (Allium cepa L.), garlic (Allium sativum L.), and their main components, such as propyl thiosulfinate oxide (PTSO) are being intended for active packaging with the purpose of maintaining and extending food product quality and shelf life. The present work aims to assess for the first time the potential mutagenicity/genotoxicity of PTSO (0–50 µM) using the following battery of genotoxicity tests: (1) the bacterial reverse-mutation assay in Salmonella typhimurium (Ames test, OECD 471); (2) the micronucleus test (OECD 487) (MN) and (3) the mouse lymphoma thymidine-kinase assay (OECD 476) (MLA) on L5178YTk^+/−, cells; and (4) the comet assay (with and without Endo III and FPG enzymes) on Caco-2 cells. The results revealed that PTSO was not mutagenic in the Ames test, however it was mutagenic in the MLA assay after 24 h of treatment (2.5–20 µM). The parent compound did not induce MN on mammalian cells; however, its metabolites (in the presence S9) produced positive results (from 15 µM). Data from the comet assay indicated that PTSO did not induce DNA breaks or oxidative DNA damage. Further in vivo genotoxicity tests are needed to confirm its safety before it is used as active additive in food packaging.     

Genotoxicity and antileishmanial activity evaluation of Physalis angulata concentrated ethanolic extract

Antileishmanial in vitro tests, as well as Ames and micronucleus assays were performed with a concentrated ethanolic extract of Physalis angulata (EEPA)ResultsEEPA did not present mutagenic effect in Salmonella typhimurium strains at concentration reaching 3000 μg/plate and did not induce mutagenic effects after two oral administrations with a 24 h interval at a dose level of 2000 mg/kg. EEPA presented antileishmanial activity and presented an IC₅₀ value of 5.35 ± 2.50 μg/mL and 4.50 ± 1.17 μg/mL against Leishmania amazonensis and Leishmania braziliensis promastigotes, respectively. In the cytotoxicity test against macrophages, the EEPA had a LC₅₀ of 6.14 ± 0.59 μg/mL. Importantly, the IC₅₀ against L. amazonensis intracellular amastigotes was 1.23 ± 0.11 μg/mL.ConclusionEEPA extract is non-mutagenic and presented a promising pharmacological effect against Leishmania parasites.     

Genotoxic effects of produced waters in mosquito fish (Gambusia affinis)

The aim of this study was to assess the potential genotoxic effects of produced water (PW) from an Italian on-shore oil plant. Produced water is a complex mixture containing residual hydrocarbons, trace elements, naturally occurring radioactive material and potentially toxic treatment chemicals such as biocides, dispersants, detergents and scale inhibitors used in oil production. The test organism, mosquito fish (Gambusia affinis), was divided into male and female groups and exposed for 8 days in the laboratory to 50% concentrations of different produced waters: PW before treatment and after settling treatment. The fish were also exposed to lower concentrations (10%) of the same PW for 30 days. DNA damage was evaluated in erythrocytes by single cell gel electrophoresis (Comet assay) and micronucleus test, while an oxidative stress biomarker, was assessed. Polycyclic aromatic hydrocarbons (PAH) metabolites in bile were also evaluated. A higher sensitivity in biomarker responses was found in females in comparison to males. An increase in DNA strand breaks was observed in both genders after 30 days exposure and a statistically significant increase of micronucleated cells was found in females after 8 days exposure. A positive correlation between presence of micronucleated cells and PAH metabolites in bile was also observed.     

Study of serum interaction with a cationic nanoparticle: Implications for in vitro endocytosis, cytotoxicity and genotoxicity

We used well-characterized and positively charged nanoparticles (NP⁺) to investigate the importance of cell culture conditions, specifically the presence of serum and proteins, on NP⁺ physicochemical characteristics, and the consequences for their endocytosis and genotoxicity in bronchial epithelial cells (16HBE14o-). NP⁺ surface charge was significantly reduced, proportionally to NP⁺/serum and NP⁺/BSA ratios, while NP⁺ size was not modified. Microscopy studies showed high endocytosis of NP⁺ in 16HBE14o-, and serum/proteins impaired this internalization in a dose-dependent manner. Toxicity studies showed no cytotoxicity, even for very high doses of NP⁺. No genotoxicity was observed with classic comet assay while primary oxidative DNA damage was observed when using the lesion-specific repair enzyme, formamidopyrimidine DNA-glycosylase (FPG). The micronucleus test showed NP⁺ genotoxicity only for very high doses that cannot be attained in vivo. The low toxicity of these NP⁺ might be explained by their high exocytosis from 16HBE14o- cells. Our results confirm the importance of serum and proteins on nanoparticles endocytosis and genotoxicity.     

大鼠鼻粘膜上皮细胞微核试验

本文报告了大鼠鼻上皮细胞微核试验。分离的鼻道粘膜以链霉蛋白酶和胶元酶消化得到上皮细胞,细胞产率为每只大鼠3.1×10~6,细胞存活率为71.6%。在涂片上,大鼠鼻上皮细胞可分为纤毛细胞、杯状细胞及其它细胞。大鼠鼻粘膜上皮自发微核率为1.76±1.2‰。以滴鼻法亚急性染毒,甲醛和二甲基亚硝胺可显著增加大鼠鼻上皮细胞微核率,并有剂量-反应关系。     

Genotoxicity of acrylamide in human hepatoma G2 (HepG2) cells

The recent finding that acrylamide (AA), a carcinogen in animal experiments and a probable human carcinogen, is formed in foods during cooking raises human health concerns. The relevance of dietary exposure for humans is still under debate. The purpose of the study was to evaluate the possible genotoxicity of acrylamide in human hepatoma G2 (HepG2) cells, a cell line of great relevance to detect genotoxic/antigenotoxic substances, using single cell gel electrophoresis (SCGE) assay and micronucleus test (MNT). In order to clarify the underlying mechanism(s) we evaluated the intracellular generation of reactive oxygen species (ROS) and the level of oxidative DNA damage by immunocytochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG). The involvement of glutathione (GSH) in the AA-induced oxidative stress was examined through treatment with buthionine sulfoximine (BSO) to deplete GSH. The results indicate that AA caused DNA strand breaks and increase in frequency of MN in HepG2 cells in a dose-dependent manner. The possible mechanism underlies the increased levels of ROS, depletion of GSH and increase of 8-OHdG formation in HepG2 cells treated with AA. We conclude that AA exerts genotoxic effects in HepG2 cells, probably through oxidative DNA damage induced by intracellular ROS and depletion of GSH.