Evaluation of the relationship between mercury exposure and oxidative DNA lesions in workers occupationally expose to mercury

Abstract

Evaluation of antioxidant status by measuring the activities of superoxidase dismutase and glutathione peroxidase and the concentrations of total reduced glutathione and protein-bound thiols in the serum, also, measuring urinary 8-hydroxy-2- deoxyguanosine (8-OHdG); which is used as biomarker of oxidative DNA damage in the mercury exposed persons was the objective of this study. The study was carried out on 40 workers exposed to mercury on the job in collaboration with National Institute of Occupational Safety and Health. Samples were collected in December 2008 from workers at fluorescent lamps and dry batteries factories. Urinary 8-hydroxy-2-deoxyguanosine (8-OHdG) was measured used as biomarker of oxidative DNA damage in the mercury exposed persons. The antioxidant status was assessed by measuring the activities of superoxidase dismutase and glutathione peroxidase and the concentrations of total reduced glutathione and protein-bound thiols were also evaluated in the serum. In this study, urinary 8-OHdG which is a metabolite of oxidized DNA was used to evaluate whether mercury exposure led to oxidative damage to DNA. The activities of serum GSH-Px and superoxide dismutase (SOD) and the concentrations of GSH and total protein-bound thiol were also investigated to clarify the relation-ship between body mercury status and oxidative stress. Forty subjects were chosen to participate in this study from workers exposed to mercury on the job. Ten healthy subjects, matching in age, sex and socio-economic status were chosen as a control group. There was increase in 8-OHdG concentrations in urine which means that DNA damage had occurred. The mercury exposed workers had significantly higher serum concentrations of GSH and protein-bound thiols than did the control groups. Serum and urinary mercury a concentration in the exposed group was more than 40 fold higher than in the controls. Measurement of urinary 8-hydroxy-2- deoxyguanosine (8-OHdG) could be useful for evaluating in vivo oxidative DNA damage in the mercury- exposed populations.