Zhang Xiaoou, Jiang Liping, Geng Chengyan, Cao Jun, Zhong Laifu
Department of Toxicology, Dalian Medical University, No. 9, Dalian 116044, Liaoning, China.
Toxicon. 2009 Sep 15;54(4):513-8. doi: 10.1016/j.toxicon.2009.05.021. Epub 2009 May 30.
Deoxynivalenol (DON) is a trichothecene mycotoxin and a cereals contamination, whose cytotoxicity has been shown in animals and various cells. However, with respect to the deoxynivalenol-induced DNA damage, especially in humans, are not well understood. The aim of this study was to assess the role of oxidative stress in deoxynivalenol-induced DNA damage, using human hepatoma HepG2 cells. Exposure of the cells to DON caused significant increase of DNA migration in comet assay at concentrations of 3.75-30 microM, which suggests that DON caused DNA strand breaks. To elucidate the role of antioxidation in those effects, DNA migration was monitored by pre-treatment with hydroxytyrosol (HT) as an antioxidant in comet assay. It was found that DNA migration with pre-treatment of HT was dramatically decreased. The DNA damage induced by DON was almost completely prevented. In order to clarify the underlying mechanisms, we evaluated the level of reactive oxygen species (ROS) production with the 2,7-dichlorofluorescein diacetate (DCFH-DA) assay. Significant increase in the level of ROS was observed in HepG2 cells at a higher concentration (60 microM). The involvement of lipid peroxidation in the DNA damage of DON was confirmed by using immunoperoxidase staining for 8-hydroxydeoxyguanosine (8-OHdG) and by measuring levels of thiobarbituric acid-reactive substances (TBARS), the doses being 7.5-60 microM and 3.75-15 microM, respectively. These results indicate that the DNA damage induced by DON in HepG2 cells is probably related to the oxidative stress.
脱氧雪腐镰刀菌烯醇（DON）是一种单端孢霉烯族霉菌毒素，可造成谷物污染，其细胞毒性已在动物和多种细胞中得到证实。然而，关于脱氧雪腐镰刀菌烯醇诱导的DNA损伤，尤其是在人类中的损伤情况，目前尚不清楚。本研究的目的是利用人肝癌HepG2细胞评估氧化应激在脱氧雪腐镰刀菌烯醇诱导的DNA损伤中的作用。在彗星试验中，当细胞暴露于浓度为3.75 - 30微摩尔的DON时，DNA迁移显著增加，这表明DON导致了DNA链断裂。为了阐明抗氧化在这些效应中的作用，在彗星试验中用抗氧化剂羟基酪醇（HT）预处理细胞，监测DNA迁移情况。结果发现，HT预处理后DNA迁移显著降低，DON诱导的DNA损伤几乎完全得到预防。为了阐明潜在机制，我们用二氯荧光素二乙酸酯（DCFH - DA）检测法评估活性氧（ROS）的产生水平。在较高浓度（60微摩尔）下，HepG2细胞中ROS水平显著增加。通过对8 - 羟基脱氧鸟苷（8 - OHdG）进行免疫过氧化物酶染色以及测量硫代巴比妥酸反应性物质（TBARS）水平，分别在7.5 - 60微摩尔和3.75 - 15微摩尔剂量下，证实了脂质过氧化参与了DON诱导的DNA损伤。这些结果表明，DON在HepG2细胞中诱导的DNA损伤可能与氧化应激有关。
