Dias Elsa, Louro Henriqueta, Pinto Miguel, Santos Telma, Antunes Susana, Pereira Paulo, Silva Maria João
Department of Environmental Health, National Institute of Health Dr. Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal.
Department of Human Genetics, National Institute of Health Dr. Ricardo Jorge, Avenida Padre Cruz, 1649-016 Lisbon, Portugal.
Biomed Res Int. 2014;2014:949521. doi: 10.1155/2014/949521. Epub 2014 May 18.
Microcystin-LR (MCLR) is a cyanobacterial toxin known for its acute hepatotoxicity. Despite being recognized as tumour promoter, its genotoxicity is far from being completely clarified, particularly in organs other than liver. In this work, we used the comet and/or the micronucleus (MN) assays to study the genotoxicity of MCLR in kidney- (Vero-E6) and liver-derived (HepG2) cell lines and in blood cells from MCLR-exposed mice. MCLR treatment (5 and 20 μM) caused a significant induction in the MN frequency in both cell lines and, interestingly, a similar positive effect was observed in mouse reticulocytes (37.5 μg MCLR/kg, i.p. route). Moreover, the FISH-based analysis of the MN content (HepG2 cells) suggested that MCLR induces both chromosome breaks and loss. On the other hand, the comet assay results were negative in Vero-E6 cells and in mouse leukocytes, with the exception of a transient increase in the level of DNA damage 30 minutes after mice exposure. Overall, the present findings contributed to increase the weight of evidence in favour of MCLR genotoxicity, based on its capacity to induce permanent genetic damage either in vitro or in vivo. Moreover, they suggest a clastogenic and aneugenic mode of action that might underlie a carcinogenic effect.
微囊藻毒素-LR（MCLR）是一种蓝藻毒素，以其急性肝毒性而闻名。尽管它被认为是肿瘤促进剂，但其遗传毒性远未完全阐明，尤其是在肝脏以外的器官中。在这项研究中，我们使用彗星试验和/或微核（MN）试验来研究MCLR对肾源细胞系（Vero-E6）和肝源细胞系（HepG2）以及暴露于MCLR的小鼠血细胞的遗传毒性。MCLR处理（5和20μM）导致两种细胞系中的微核频率显著升高，有趣的是，在小鼠网织红细胞中也观察到类似的阳性效应（腹腔注射途径给予37.5μg MCLR/kg）。此外，基于荧光原位杂交（FISH）对微核含量的分析（HepG2细胞）表明，MCLR可诱导染色体断裂和丢失。另一方面，彗星试验结果在Vero-E6细胞和小鼠白细胞中为阴性，不过小鼠暴露30分钟后DNA损伤水平有短暂升高。总体而言，基于MCLR在体外或体内诱导永久性遗传损伤的能力，目前的研究结果有助于增加支持其遗传毒性的证据权重。此外，这些结果表明其可能存在致断裂和致非整倍体的作用模式，这可能是致癌作用的基础。
