Alterations of liver function test indices of filling station workers with respect of genetic polymorphisms of GSTM1 and GSTT1

Abstract

To determine the health effects of gasoline exposure on liver function test indices of filling station workers the present study was done. This case-control study was conducted in Shiraz on 56 male gasoline workers and 56 age- and sex-matched control subjects with no occupational exposure to gasoline. To elucidate the role of hepatic detoxifying enzymes, the genotypes of glutathione- S-transferases (GST) M1 and T1 were determined. Data analysis was done by multiple linear regression analysis and non-parametric Kruskal–Wallis test. The present study showed that all measurements were in normal range, although sub-clinical changes were detected in some indices. In liver function tests, exposure was associated with lower serum albumin ( t=−3.88, P<0.001) and total proteins ( t=−3.016, P=0.003) but higher alanine aminotransferase ( t=2.856, P=0.005) and aspartate aminotransferase ( t=2.11, P=0.038) levels in workers comparing to controls. Other investigators reported that GSTs involved in detoxification of several toxins including some of the compounds present in gasoline. Therefore, the possible influence of GSTT1 and GSTM1 genetic polymorphisms on alteration of liver function tests indices was investigated. The present findings showed that the genotype combinations of GSTM1 and GSTT1 did not alter the effects of exposure to gasoline in workers except for serum albumin. Serum albumin significantly decreased in workers with both active GST enzymes who had more than 5 years of employments ( P=0.01). It is suggested that GSTM1 and GSTT1 are not involved in detoxification of toxicants present in gasoline which are hazardous to liver. Overall, due to detection of sub-clinical changes in hepatic test in gasoline station workers, exposure limitation and administrating safety device are recommended.