Genotoxic evaluation of different doses of methylmercury (CH3Hg+) in Hoplias malabaricus

• Published in: Ecotoxicology and environmental safety 2012-08, Vol.82, p.47-55
• Main Authors: Vicari, Taynah, Ferraro, Marcos Vinícius Mocellin, Ramsdorf, Wanessa Algarte, Mela, Maritana, de Oliveira Ribeiro, Ciro Alberto, Cestari, Marta Margarete
• Format: Article
• Language: English
• Subjects: Agnatha. Pisces; Animal, plant and microbial ecology; Animals; Applied ecology; aquatic environment; Astyanax; bioaccumulation; Biological and medical sciences; blood sampling; Characiformes - genetics; Comet Assay; DNA Damage - drug effects; Ecotoxicology, biological effects of pollution; Erythrocytes - drug effects; fish; Food Chain; food webs; Fundamental and applied biological sciences. Psychology; General aspects; genotoxicity; Hoplias malabaricus; Kidney - drug effects; kidney cells; kidneys; mechanism of action; metals; methylmercury compounds; Methylmercury Compounds - toxicity; Micronucleus Tests; surveys; Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution; Water Pollutants, Chemical - toxicity
• ISSN: 0147-6513; 1090-2414
• DOI: 10.1016/j.ecoenv.2012.05.007

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 CH3Hg+/g and 0.75 μg CH3Hg+/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. ► Methyl mercury is a great concern as a water contaminant, increasing the risk to aquatic food webs. ► The aim of this study was to evaluate the genotoxic damage caused by methyl mercury in a fish species. ► For comet assay in erythrocytes the results showed a genotoxic activity of methyl mercury. ► The comet assay in kidney cells indicates mechanisms of action of methyl mercury not yet elucidated.