Role of Glutathione-S-Transferase Polymorphism on Arsenic-Induced Protein Carbonylation and Urinary Deoxy Guanosine Status

Oxidative stress is significantly associated with chronic arsenic exposure in persons exposed to moderate-to-high level of environmental arsenic. However, the response varies widely among persons within similar exposure level. To study whether Glutathione-S-Transferase (GST) gene polymorphism plays any pivotal role in this variation, total number of 115 chronic arsenic-exposed study subjects without arsenic-induced cancer from School of Tropical Medicine, Kolkata and from arsenic-exposed districts of West Bengal were recruited for this study. Concentration of arsenic in their urine and water, extent of clinical manifestation, GST status and protein carbonylation, and 8-oxo-2 '-deoxyguanosine status were determined. Genetic polymorphism of GSTM1 and T1 were significantly associated (p < 0.05) with degree of protein carbonylation and 8-oxo-2 '-deoxyguanosine in moderate-to-high degree of arsenic exposure groups. Persons having null genotype have significantly increased level of protein carbonylation and 8-oxo-2 '-deoxyguanosine in comparison to persons with GSTM1 or GSTT1 non-null genotype of the same arsenic exposure group. Degree of protein carbonylation and urinary 8-oxo-2-deoxyguanosine is positively correlated with GST null genotype.