Yao Xiaofeng, Zhong Laifu
Department of Toxicology, Dalian Medical University, 465 Zhongshan Road, Dalian, 116027 Liaoning, China.
Mutat Res. 2005 Nov 10;587(1-2):38-44. doi: 10.1016/j.mrgentox.2005.07.010. Epub 2005 Oct 10.
Perfluorooctanoic acid (C8HF15O2, PFOA) is widely used in various industrial fields for decades and it is environmentally bioaccumulative. PFOA is known as a potent hepatocarcinogen in rodents. But it is not yet clear whether it is also carcinogenic in humans, and the genotoxic effects of PFOA on human cells have not yet been examined. In this study, the genotoxic potential of PFOA was investigated in human hepatoma HepG2 cells in culture using single cell gel electrophoresis (SCGE) assay and micronucleus (MN) assay. In order to clarify the underlying mechanism(s) we measured the intracellular generation of reactive oxygen species (ROS) using dichlorofluorescein diacetate as a fluorochrome. The level of oxidative DNA damage was evaluated by immunocytochemical analysis of 8-hydroxydeoxyguanosine (8-OHdG) in PFOA-treated HepG2 cells. PFOA at 50-400 microM caused DNA strand breaks and at 100-400 microM MN in HepG2 cells both in a dose-dependent manner. Significantly increased levels of ROS and 8-OHdG were observed in these cells. We conclude that PFOA exerts genotoxic effects on HepG2 cells, probably through oxidative DNA damage induced by intracellular ROS.
全氟辛酸（C8HF15O2，PFOA）数十年来广泛应用于各种工业领域，且具有环境生物累积性。PFOA在啮齿动物中是一种强效肝癌致癌物。但它对人类是否也具有致癌性尚不清楚，而且PFOA对人类细胞的遗传毒性作用尚未得到研究。在本研究中，利用单细胞凝胶电泳（SCGE）试验和微核（MN）试验，在培养的人肝癌HepG2细胞中研究了PFOA的遗传毒性潜力。为了阐明潜在机制，我们使用二氯荧光素二乙酸酯作为荧光染料测量了细胞内活性氧（ROS）的生成。通过对PFOA处理的HepG2细胞中的8-羟基脱氧鸟苷（8-OHdG）进行免疫细胞化学分析，评估了氧化DNA损伤的水平。50 - 400 microM的PFOA在HepG2细胞中均以剂量依赖方式导致DNA链断裂，在100 - 400 microM时导致微核形成。在这些细胞中观察到ROS和8-OHdG水平显著升高。我们得出结论，PFOA可能通过细胞内ROS诱导的氧化DNA损伤对HepG2细胞产生遗传毒性作用。
