Polymorphisms of GSTT1 and GSTM1 and increased micronucleus frequencies in peripheral blood lymphocytes in residents at an e-waste dismantling site in China

摘要

In the present study, we investigated whether genetic polymorphisms of metabolic enzymes in an exposed population were associated with genotoxic effects of the pollutants from e-waste in 58 subjects (the exposed) resided in a typical e-waste recycling site and 80 subjects (the controls) from a village away from the recycling site. Effects of genetic polymorphisms of glutathione S-transferases (GSTs) (GSTT1 and GSTM1) on the frequency of micronucleated binucleated cells (Mned BNC) in peripheral blood lymphocytes were evaluated. GSTM1 and GSTT1 were typed using PCR-restriction fragment length polymorphism methods. Cytogenetic alterations were evaluated using the cytokinesis-block micronucleus assay. The Mned BNC frequency was significantly higher in the exposed group (median: 4.0‰, IQR: 2.0-7.0‰) than in the control group (median: 1.0‰, IQR: 0.0-2.0‰, P < 0.01 for both comparisons); sera GST activities were also higher in the exposed subjects with either non-null GSTT1 (mean ± SD: 20.27 ± 6.43) or non-null GSTM1 (mean ± SD: 19.71 ± 4.89) than in the controls (mean ± SD: 18.79 ± 4.91 and 19.34 ± 6.42, respectively, P < 0.05 for both). Although the increased Mned BNC frequencies among the exposed group may be associated with the co-exposure of various chemical pollutants in the environment, there was no statistical evidence of an association between GSTs genotypes and frequencies of micronuclei in the study population. Because this study size was small, the mechanism of genotoxic effects caused by exposure to e-waste needs to be further validated in larger studies.