Effect of acrylamide treatment on the activity and expression of glutathione-S-transferase in rat hepatocytes

Abstract

Acrylamide (AA) is carcinogen, mutagen and neurotoxic substance present in fried, roasted and baked starch-based goods. AA is formed in Maillard reaction from asparagine and carbonyl sources, such as reducing sugars, during thermal food processing at temperatures between 120°C and 180°C. The aim of our study was to determine whether acrylamide treatment affects the expression and activity of glutathione-S-transferase (GST) in hepatocyte. Viability of rat hepatoma cell line - H4IIE upon AA treatment was assessed by the MTT viability assay. Cells were cultivated in a 96-well plate and exposed to increasing concentrations of AA (2.5–5.5 mM) for 24 h. AA concentration of 4 mM induced death of 17.62% H4IIE cells, while 4.5 mM AA caused death of 48.45% cells. Therefore, AA concentrations of 4 mM and 4.5 mM were taken as IC20 and IC50, respectively. H4IIE cells were treated with IC20 and IC50 of AA for 24 h. Relative mRNA expression for GSTA2 and GSTP1 was quantified using real-time RT-PCR. Total GST activity was determined spectrophotometrically at 340 nm using DTNB as the substrate. After AA treatments, mRNA level for GSTA2 and GSTP1 and total GST activity increased in a concentration-dependent manner in H4IIE cells. Only treatment with higher AA concentration (4.5 mM) proved to be statistically significant for all three examined parameters. Our results indicate that by altering expression and activity of GST enzyme acrylamide exerts toxic effects on hepatocytes.