Hydroquinone-induced genotoxicity and oxidative DNA damage in HepG2 cells
Hydroquinone-induced genotoxicity and oxidative DNA damage in HepG2 cells
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对苯二酚诱导的 HepG2 细胞遗传毒性和氧化 DNA 损伤
DOI：
10.1016/j.cbi.2008.02.002
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发表时间：
2008-05-09
影响因子：
5.1
通讯作者：
Zhong, Laifu
中科院分区：
文献类型：
--
作者：
Luo, Lihan;Jiang, Liping;Zhong, Laifu
对苯二酚（HQ）在橡胶工业中用作抗氧化剂，在摄影中用作显影剂。 HQ也是制造橡胶、食品抗氧剂和单体抑制剂的中间体。然而，其影响机制，特别是与人类遗传毒性相关的机制，尚不清楚。本研究的目的是使用人肝癌 HepG2 细胞评估 HQ 的基因毒性作用，并确定和阐明其机制。 DNA 链断裂和 DNA-蛋白质交联 (DPC) 通过蛋白酶 K 修饰的碱性单细胞凝胶电泳 (SCGE) 测定进行测量。使用 SCGE 测定，在 HQ 浓度（6.25-25 μM）下检测到 DNA 迁移的显着剂量依赖性增量；但在较高的测试浓度（50 μM）下，与 25 μM 时的最大迁移相比，观察到迁移减少。与蛋白酶 K 一起孵育后，暴露于较高浓度 HQ (50 muM) 的细胞中 DNA 迁移显着增加。微核试验(MNT)中发现，在12.5至50μM范围内，微核频率显着增加。数据表明 HQ 导致 DNA 链断裂、DPC 和染色体断裂。为了阐明氧化 DNA 损伤机制，选择 2,7-二氯荧光素二乙酸酯 (DCFH-DA) 和邻苯二甲醛 (OPT) 分别监测活性氧 (ROS) 和谷胱甘肽 (GSH) 的水平。本研究表明，HQ可诱导HepG2细胞中ROS水平升高和GSH消耗，剂量分别为25-50和6.25-50μM。此外，HQ在12.5至50μM的浓度下显着引起HepG2细胞中8-羟基脱氧鸟苷(8-OHdG)的形成。所有这些结果表明HQ在HepG2细胞中发挥基因毒性作用，可能是通过氧化应激引起的DNA损伤。 GSH 作为一种主要的细胞内抗氧化剂，负责细胞防御 HQ 诱导的 DNA 损伤。 (C) 2008 Elsevier Ireland Ltd. 保留所有权利。
Hydroquinone (HQ) is used as an antioxidant in rubber industry and as a developing agent in photography. HQ is also an intermediate in the manufacture of rubber, food antioxidant and monomer inhibitor. However, the mechanisms of the effects, in particular those related to its genotoxicity in humans, are not well understood. The aim of this study was to assess the genotoxic effects of HQ and to identify and clarify the mechanisms, using human hepatoma HepG2 cells. DNA strand breaks and DNA-protein crosslinks (DPC) were measured by the proteinase K-modified alkaline single cell gel electrophoresis (SCGE) assays. Using the SCGE assay, a significant dose-dependent increment in DNA migration was detected at concentrations of HQ (6.25-25 mu M); but at the higher tested concentrations (50 mu M), a reduction in the migration compared to the maximum migration at 25 mu M was observed. Post-incubation with proteinase K significantly increased DNA migration in cells exposed to higher concentrations of HQ (50 mu M). A significant increase of the frequency of micronuclei was found in the range from 12.5 to 50 mu M in the micronucleus test (MNT). The data suggested that HQ caused DNA strand breaks, DPC and chromosome breaks. To elucidate the oxidative DNA damage mechanism, the 2,7-dichlorofluorescein diacetate (DCFH-DA) and o-phthalaldehyde (OPT) were chosen to monitor the levels of reactive oxygen species (ROS) and glutathione (GSH), respectively. The present study showed that HQ induced the increased levels of ROS and depletion of GSH in HepG2 cells, the doses being 25-50 and 6.25-50 mu M, respectively. Moreover, HQ significantly caused 8-hydroxydeoxyguanosine (8-OHdG) formation in HepG2 cells at concentrations from 12.5 to 50 mu M. All these results demonstrate that HQ exerts genotoxic effects in HepG2 cells, probably through DNA damage by oxidative stress. GSH, as a main intracellular antioxidant, is responsible for cellular defense against HQ-induced DNA damage. (C) 2008 Elsevier Ireland Ltd. All rights reserved.