Results of Studying Genotoxic Effects of Dioxins Depending on Polymorphisms of Xenobiotic Detoxification Genes and the Length of Service of Firefighters

Abstract

Introduction: The work of firefighters is associated with a high risk to health and life. During firefighting, firemen are exposed to a combination of various factors, among which chemical agents rank first. Of all the toxic products of combustion, the most dangerous are genotoxic substances having a high cumulative effect and a very long clearance time, including dioxins and dioxin-like polychlorinated biphenyls generated during low-temperature combustion of organic chlorine compounds. Objective: To study karyopathological manifestations of the genotoxic effects of dioxins in firefighters, de¬pending on the length of service and various polymorphic variants of the xenobiotic detoxification genes. Materials and methods: The cytogenetic status of firefighters was assessed using an extended micronucleus test of buccal epithelium. The study was conducted in 2019–2022 involving 252 firefighters, 86 rescuers and other professionals. The risk of cytogenetic abnormalities in epitheliocytes was assessed using calculation methods and expressed as an index of accumulation of cytogenetic disorders. For each subject, two smears of buccal epithelium were prepared followed by the analysis of two thousand intact cells. Results: We noted an increase in the frequency of karyotype aberrations in buccal epithelial cells of firefighters compared to controls correlating with the length of service and dioxin concentrations in blood lipids. The analysis of the relationship between various polymorphic variants of xenobiotic detoxification genes, dioxins in blood lipids of firefighters, and the index of accumulation of cytogenetic damage showed that individuals with a combination of six genotypes (EPHX1 Tyr/Tyr, CYP1A1 A/A, GSTT1 I/I, GSTM1 I/I, GSTP1 A /A, and GSTP1 C/C) possessed xenobiotic detoxification enzymes with high activity and better resistance to karyotypic changes induced by genotoxicants. Conclusion: The levels of cytogenetic disorders established in the present study give evidence of adverse health effects of occupational exposure to toxic combustion products in firefighters of the State Fire Service of the Russian Ministry of Emergency Situations.