Effects of genetic polymorphisms of GSTM1, GSTT1, and GSTP1 genes on blood metal levels in non-ferrous metal alloy smelter operators

Abstract

Heavy metal ions are known to induce generation of a large number of reactive oxygen species (ROS). Glutathione S-transferases (GSTs) play an important role in adaptation and response to oxidative stress. GSTM1, GSTT1, and GSTP1 genes have numerous described polymorphisms, the most significant being GSTM1, GSTT1, and GSTP1 Ile105Val deletion ones. Our objective was to study the relationship between the genetic polymorphism of GSTM1, GSTT1, GSTP1 genes and blood levels of metals in smelter operators engaged in crude lead refining. We examined 55 male lead-refining furnace operators working at a non-ferrous metal alloy plant. Blood metal concentrations were measured by inductively coupled plasma mass spectrometry. GSTM1 and GSTT1 deletion polymorphisms were determined using real-time SYBR Green qPCR and that of GSTP1 Ile105Val – using a commercial SNP Screening Kit. Statistical data processing was carried out using the Mann – Whitney U-test. Blood levels of industry-specific metals were not statistically different between the workers with GSTT1 and GSTP1 genotypes. We established, however, that men with the null genotype of GSTM1 had significantly higher blood arsenic levels. Our findings indicate that a high blood arsenic level associated with occupational exposure may be attributed to the GSTM1 null genotype. This observation can be used to identify the most vulnerable groups of individuals at risk of overexposure to arsenic.