Evaluation of Primary DNA Damage, Cytogenetic Biomarkers and Genetic Polymorphisms for CYP1A1 and GSTM1 in Road Tunnel Construction Workers

Abstract

In tunnel construction workers, occupational exposure to dust (α-quartz and other particles from blasting), gases (nitrogen dioxide, NO₂), diesel exhausts, and oil mist has been associated with lung function decline, induction of inflammatory reactions in the lungs with release of mediators that may influence blood coagulation, and increased risk of chronic obstructive pulmonary disease. The present molecular epidemiology study was designed to evaluate whether occupational exposure to indoor pollutants during road tunnel construction might result in genotoxic effects. A study group of 39 underground workers and a reference group of 34 unexposed subjects were examined. Primary and oxidative DNA damage, sister-chromatid exchanges (SCE), and micronuclei (MN) were measured in peripheral blood cells. The possible influences of polymorphisms in gene encoding for CYP1A1 and GSTM1 xenobiotic-metabolizing enzymes were also investigated. Exposure assessment was performed with detailed interviews and questionnaires. There were no significant differences in the level of primary and oxidative DNA damage and frequency of SCE between the tunnel workers and controls, whereas the frequency of MN showed a significant increase in exposed subjects compared to controls. No effects of CYP1A1 or GSTM1 variants were observed for the analyzed biomarkers. Since MN in peripheral blood lymphocytes are recognized as a predictive biomarker of cancer risk within a population of healthy subjects, the genotoxic risk of occupational exposure to various indoor environmental pollutants during road tunnel construction cannot be excluded by this biomonitoring study.

This work was partially supported by a grant from ISPESL—Istituto Superiore per la Prevenzione e la Sicurezza del Lavoro (Research No. B10/DOC/02). The authors thank the construction tunnel workers for participating in the study and express their gratitude to the blood donors (AVIS Umbertide) who served as the controls. We are indebted to the nursing staff of the Transfusion Center at the Umbertide Hospital for their valuable contribution. We also thank Prof. Giuseppina Scassellati-Sforzolini, Emeritus Professor of Hygiene, University of Perugia, for her assistance during this research and her constructive comments on the article.