Departamento de Genética, Laboratório de Mutagênese Ambiental, Universidade Federal do Paraná (UFPR), Curitiba, PR, Brazil.
Ecotoxicol Environ Saf. 2012 Aug;82:47-55. doi: 10.1016/j.ecoenv.2012.05.007. Epub 2012 Jun 6.
The survey of the effects of toxic metals and its organic compounds are of critical importance because these compounds tend to accumulate in aquatic environments. In the present work, the genotoxic potential of methylmercury, an organomercurial compound with high toxicity and present in large amounts in fish of the Amazon due to the mining process, was evaluated using the piscine micronucleus test and comet assay in fish. Specimens of Hoplias malabaricus (popularly known as traira), a neotropical specie, was exposed to methylmercury via food web, over 70 days, in two different concentrations: two groups of fifteen fish were tested with 0.075 μg CH(3)Hg(+)/g and 0.75 μg CH(3)Hg(+)/g of methylmercury per gram of fish, at 5-day intervals and over 14 successive intervals whereas control group, composed by nine fish, was fed by uncontaminated prey fish (Astyanax sp). One of the aims of this study was to reproduce the contamination found in nature in an attempt to increase our biological knowledge on the neotropical species. Hoplias malabaricus specimens were then anesthetized for removal of blood samples and dissected, for cephalic kidney removal. As a result, it was observed that the piscine micronucleus test showed no significant differences between exposed groups and control group. The comet assay performed on erythrocyte system cells, showed a significant difference between controls and contaminated, but there was no difference between doses. In contrast, the kidney cells comet assay showed no significant difference between groups, probably due to the type of damage caused by xenobiotics to be related to the tissues of most contact with it, as well as its mode of action and the chain of bioaccumulation within bodies.
本次研究旨在通过食物网的方式，利用鲶鱼（Hoplias malabaricus），一种生活在亚马逊流域的热带鱼，来模拟自然界中甲基汞的污染情况，评估甲基汞（一种毒性很强且在亚马逊流域的鱼类中大量存在的有机汞化合物）对鱼类的遗传毒性。研究人员将 15 条鲶鱼分为两组，分别投喂甲基汞浓度为 0.075 μg CH(3)Hg(+)/g 和 0.75 μg CH(3)Hg(+)/g 的食物，每 5 天投喂一次，共投喂 14 次；对照组 9 条鲶鱼投喂未受污染的小鱼。研究目的之一是模拟自然界中的污染情况，以增加我们对热带鱼类的生物学认识。实验结束后，研究人员对鲶鱼进行麻醉，采集血液样本并解剖，取出头部肾脏组织。结果表明，鱼类微核试验未显示暴露组与对照组之间存在显著差异。红细胞彗星试验显示，对照组与污染组之间存在显著差异，但两组之间的剂量无差异。相反，肾脏细胞彗星试验显示，各组之间无显著差异，这可能与污染物对与污染物接触最频繁的组织造成的损伤类型以及其作用方式和体内生物累积链有关。
