Urinary 8-Hydroxydeoxyguanosine as a Biomarker of Oxidative DNA Damage in Workers Exposed to Ethylbenzene

Abstract

This study assessed the relationships between ethylbenzene exposure and levels of 8-hydroxydeoxyguanosine (8-OHdG) among spray painters. Sixty-four male workers employed at a large shipyard were recruited for this investigation. Fifteen spray painters exposed to paint, together with two non-exposed groups, namely 19 sandblasting workers and 30 office staffs were selected as the subjects. Personal exposure to xylene and ethylbenzene in air were collected using diffusive samplers. Urine samples of the spray painters were collected after a month-long holiday leave and during the pre- and post-workshifts. Urine samples of sandblasting workers and office staffs were gathered after their shift. Urinary mandelic acid and methyl hippuric acid were used as biological indices of dose of ethylbenzene and xylene, respectively. Urinary 8-OHdG was used as biomarker of oxidative DNA damage. The post-workshift concentration of urinary 8-OHdG for 10 spray painters (30.3 ± 9.28 μg g(-1) creatinine) significantly exceeded that of holiday leave (7.20 ± 1.08 μg g(-1) creatinine; P = 0.001). The post-workshift concentration of urinary 8-OHdG was higher among 15 spray painters (29.0 ± 6.52 μg g(-1) creatinine) than sandblasting workers (9.14 ± 2.05 μg g(-1) creatinine; P = 0.01) and office staffs (8.35 ± 0.84 μg g(-1) creatinine; P = 0.007). A stepwise regression model revealed an 8.11 μg g(-1) creatinine increase per 1 p.p.m. increase in ethylbenzene [95% confidence interval (CI) 4.13-12.1]. A stepwise regression model revealed an increase of 6.04 μg g(-1) creatinine (95% CI 2.23-9.84) per 1 p.p.m. in ethylbenzene after adjustment of age (95% CI 2.23-9.84). This pilot study suggests that occupational exposure to paint increases oxidative DNA injury. Moreover, urinary 8-OHdG levels displayed greater DNA damage in spray painters compared to other unexposed groups and their holiday leave samples. A significant correlation was found between urinary 8-OHdG and the exposure to ethylbenzene. The ethylbenzene exposure could not explain all urinary 8-OHdG measured. Other components of paint deserve further investigation.