Impact of GSTM1, GSTT1, GSTP1 polymorphism and environmental lead exposure on oxidative stress biomarkers

Oxidative stress and genetic related to antioxidants could have influence on susceptibility to lead (Pb) toxicity. In this study, we aim to examine the effects of genetic variations of glutathione S-transferase (GST) gene on oxidative stress alterations (by the measurements of malondialdehyde; MDA and glutathione; GSH) among general population. Real-time-PCR with Taqman probes was performed to analyze GSTM1, GSTT1 and GSTP1 Ile105Val. Blood lead and GSH levels were determined by spectrophotometer. MDA level was measured by HPLC with fluorescence detector. Mean blood Pb level in this study group was 4.85 µg/dl (ranged 2.00 and 18.50 µg/dl). Gender, cigarette smoking and alcohol consumption affected significant blood Pb levels. To further investigation, blood Pb levels were calculated into 3 tertiles and statistical results found only in tertile 3. Individuals with the Val/Val allele for GSTP1-105 had higher blood Pb, and MDA levels but lower GSH level as compared to individuals with Ile/Ile genotype (p < 0.05). Similar results were found in GSTM1 deletion, except for the GSH levels. In contrast, no effects of GSTT1 on three parameters were observed. Our findings support consideration of genetic variations of GSH-related genes as the important risk factor for lead toxic effects in the general population with environmental exposure. Key words: Lead, glutathione S-transferase, polymorphisms, glutathione, malondialdehyde.