Direct and Oxidative DNA Damage in a Group of Painters Exposed to VOCs: Dose – Response Relationship

Abstract

Volatile organic compounds (VOCs) are present in several working activities. This work is aimed at comparing oxidative stress and DNA damage biomarkers to specific VOCs in the occupational exposure of painters. Dose-response relationships between biomarkers of oxidative stress and of dose were studied. Unmetabolized VOCs and their urinary metabolites were analyzed. Urinary Methylhyppuric acids (MHIPPs, xylenes metabolite), Phenylglyoxylic and Mandelic acid (PGA, MA ethylbenzene metabolites), S-Benzylmercapturic acid (SBMA, toluene metabolite), and S-Phenylmercapturic acid (SPMA, benzene metabolite) were quantified at the end of work-shift. Oxidative stress was determined by: urinary excretion of 8-oxodGuo, 8-oxoGua and 8-oxoGuo and direct/oxidative DNA damage in blood by Fpg-Comet assay. Multivariate linear regression models were used to assess statistical significance of the association between dose and effect biomarkers. The regressions were studied with and without the effect of hOGG1 and XRCC1 gene polymorphisms. Statistically significant associations were found between MHIPPs and both 8-oxoGuo and oxidative DNA damage effect biomarkers measured with the Comet assay. Oxidative DNA damage results significantly associated with airborne xylenes and toluene, whilst 8-oxodGuo was significantly related to urinary xylenes and toluene. Direct DNA damage was significantly associated to SBMA. XRCC1 wild-type gene polymorphism was significantly associated with lower oxidative and total DNA damage with respect to heterozygous and mutant genotypes. The interpretation of the results requires some caution, as the different VOCs are all simultaneously present in the mixture and correlated among them.

Occupational Exposure in Industrial Painters: Sensitive and Noninvasive Biomarkers to Evaluate Early Cytotoxicity, Genotoxicity and Oxidative Stress

“…The results relative to urinary biomarkers of oxidative stress, partially (those relative to exposed subjects) previously published [ 20 , 23 ], and those regarding biomarkers of inflammation are reported in Table 7 . In this Table a significant increase of urinary 8-oxoGuo and a decrease of 8-oxodGuo and 8-oxoGua are shown in both painters groups concerning controls and in painters taken all together.…”

“…In this study, several biomarkers of cyto-genotoxicity, oxidative and inflammatory effects, such as BMcyt and Fpg-comet assays, urinary oxidative DNA bases and cytokine release detection, were applied to painters, who represent a category of workers exposed to complex chemical mixtures. The painters were previously characterized for VOC exposure, with values of potential inhalation exposure to each solvent below the relative Occupational Exposure Limits, and toluene and xylenes resulted at the highest concentrations in the mixture [ 20 , 23 ].…”

“…However, in both painters groups, the values of xylenes, toluene and ethylbenzene urinary metabolites were all well below the biological exposure indexes (BEI) given by the ACGIH. Although the exposure levels are quite close to the threshold limit value (TLV) for the mixture regarding the airborne concentration, in the case of the spray painters, the personal protective equipment can effectively reduce the internal exposure [ 23 ].…”

“…Personal exposure to organic solvents and biological monitoring results on the same workers have been previously published [ 20 , 23 ]. In particular, airborne ethyl acetate, n-butyl-acetate, o-xylene, m-xylene, p-xylene, toluene, ethylbenzene were measured during the whole work-shift and the urinary metabolites of xylenes (2,3 and 4 methyl hippuric acids—MHIPP), toluene (S-benzyl mercapturic acid—SBMA) and ethylbenzene (phenylglyoxylic and mandelic acid—PGA and MA) were measured in the urine before and after the work shift.…”

“…In the present study, we evaluated cyto-genotoxic, oxidative and inflammatory effects of painters, comparing them with those of a control group of unexposed subjects considering either the painters all together or each painter group (roller and spray) according to the specific task. In addition, we correlated the observed effects in exposed workers with the previously published VOC exposure monitoring data [ 20 , 23 ]. The study design details are reported in Figure 1 .…”