Efeito toxicogenético do polimorfismo Ala16Val do gene MnSOD em leucócitos expostos in vitro ao metil mercúrio

Abstract

The environmental contamination by methyl mercury (MeHg) is a great health public problem in some world regions like Amazonia. The MeHg toxic effects seem to be influenced by environmental and genetic factors. However, there are few studies evaluating the genetic influence on MeHg toxicity in humans. Therefore, the aim of this present study was to evaluate the genetic influence of Ala16Val superoxide dismutase manganese dependent gene polymorphism (Ala16Val-MnSOD) on cytotoxic effects of in vitro human leucocytes exposed to MeHg. Subjects were selected from 100 individuals genotyped to Ala16Val-MnSOD polymorphism (26,4±7,3 years) with different genotpypes (AA=08, VV=06 and AV=12) to perform the in vitro tests. The reactive oxygen species (ROS) production was measured using 2� 7�-dichlorofluorescein diacetate (DCFDA) fluorimetric assay and the cell viability was measured using the MTT assay were performed in leucocyte samples with the same subjects exposed and not exposed to MeHg (2,5μM for 6h). The results showed that AA and VVleucocytes exposed to MeHg did not increase the ROS levels when compared to the cells that were not exposed. However, the AV-leucocyte MeHg exposure increased the ROS levels. The cellular viability comparison among different genotypes exposed to MeHg showed lower AAleucocyte viability when compared to VV-leucocytes, whereas heterozygous cells (AV) presented intermediary values. This occurred probabibly due to the fact of AA-leucocytes present a higher basal H2O2 production than other genotypes. The whole of these results suggests toxicogenetic effects of Ala16Val-SOD polymorphism in human cells exposed to MeHg.