Academic journal article Environmental Health Perspectives

Elevated Levels of Urinary 8-Hydroxy-2'-Deoxyguanosine, Lymphocytic Micronuclei, and Serum Glutathione S-Transferase in Workers Exposed to Coke Oven Emissions

Academic journal article Environmental Health Perspectives

Elevated Levels of Urinary 8-Hydroxy-2'-Deoxyguanosine, Lymphocytic Micronuclei, and Serum Glutathione S-Transferase in Workers Exposed to Coke Oven Emissions

Article excerpt

To investigate associations among occupational exposure to coke oven emissions (COEs), oxidative stress, cytogenotoxic effects, change in the metabolizing enzyme glutathione S-transferase (GST), and internal levels of polycydic aromatic hydrocarbons (PAHs) in coke oven workers, we recruited 47 male coke oven workers and 31 male control subjects from a coke oven plant in northern China. We measured the levels of 1-hydroxypyrene (1-OHP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine, micronucleated binucleated cells (BNMNs) in peripheral blood lymphocyte, and GST in serum. Our results showed that the group exposed to COEs had significantly increased levels of 1-OHP [median 5.7; interquartile range (IQR), 1.4-12.0 [micro]mol/mol creatinine] compared with the control group (3; 0.5-6.4 [micro]mol/mol creatinine). In addition, the median levels (IQR) of 8-OHdG, BNMNs, and GST were markedly increased in the exposed [1.9 (1.4-15.4) [micro]mol/mol creatinine; 6 (2-8) per thousand; 22.1 (14.9-31.2) U/L, respectively] compared with controls [1.3 (1.0-4.0) [micro]mol/mol creatinine, 2 (0-4) per thousand; and 13.1 (9.5-16.7) U/L, respectively]. These results appeared to be modified by smoking. However, multivariate logistic regression analysis revealed that exposure to COEs had the highest odds ratio among variables analyzed and that smoking was not a significant confounder of the levels of studied biomarkers. Overall, the present findings suggest that COE exposure led to increased internal PAH burden, genetic damage, oxidative stress, and GST activity. The consequences of the changes in these biomarkers, such as risk of cancer, warrant further investigations. Key words: coke oven emissions, glutathione S-transferase, 8-hydroxy-2'-deoxyguanosine, 1-hydroxypyrene, micronuclei. doi:10.1289/ehp.8562 available via http://dx.doi.org/ [Online 15 December 2005]

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Coke oven emissions (COEs) are formed and released into the environment when coal is pyrolyzed into coke (National Toxicology Program 2002). Epidemiologic studies have shown that occupational exposure to COEs during the coking process lead to increased incidence of pulmonary and prostate cancers among coke oven workers (Costantino et al. 1995). COEs are complex mixtures containing a large number of polycyclic aromatic hydrocarbons (PAHs), which are carcinogenic and mutagenic to humans [International Agency for Research on Cancer (IARC) 1987]. Hence, identification of early biomarkers for occupational exposure to PAHs may lead to effective preventive measures to reduce exposure to COEs and related health effects.

Oxygen radicals generated by environmental agents and endogenous processes may induce damage to DNA (Halliwell 1994). For instance, 8-hydroxy-2'-deoxyguanosine (8-OHdG) represents an important product from oxidative damage to DNA. 8-OHdG is formed in a promutagenic DNA lesion induced by the reaction of hydroxyl radicals with guanosine at the C8 site in DNA (Kasai et al. 1986). Oxidative stress may be implicated in aging, carcinogenesis, and other degenerative diseases, and the analysis of urinary excretion of 8-OHdG is a useful approach to assess individual cancer risk due to oxidative stress (Kasai 1997).

The micronucleus (MN) assay is a widely used genotoxic assay to detect both dastogenic and aneugenic potencies of genotoxic agents or radiation (Ramalho et al. 1988). Numerous epidemiologic studies have suggested that chromosomal alterations including formation of MNs may serve as an effective biomarker to estimate cancer risk (Hagmar et al. 1998). In particular, the MN assay in peripheral blood lymphocytes has been extensively used as a standard method to evaluate the presence and the extent of chromosome damage in workers occupationally exposed to genotoxic agents (Bonassi et al. 2001).

Xenobiotic metabolizing enzymes play a key role in chemical carcinogenesis and are often used as biomarkers to evaluate exposure and effect of organic pollutants (van der Oost et al. …

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