Effects of trichotecene mycotoxins on gene expression and activity of glutathione redox system in common carp (Cyprinus carpio L.)

The purpose of present study was to evaluate the short- and long-term effects of T-2 toxin and deoxynivalenol (DON) in common carp. Short-term effect was evaluated using single oral doses of DON or T-2 toxin of 0.25, 0.50 or 3.00 mg/kg b.w.. Experimentally contaminated or control complete feed was given by gavage directly into the stomach. Hepatopancreas samples were taken from 6 carps of each group at every 8th hour during a 24-hour long experimental period. The long-term effect was evaluated in 4 weeks in a feeding trial using 0.05 mg T-2 toxin/kg b.w. and 0.06 mg DON/kg b.w., where hepatopancreas samples were taken from 6 carps of each group weekly. Reduced glutathione (GSH) concentration and activities of glutathione-peroxidase (GPx), glutathione reductase (GR) and glutathione-S-transferase (GST) were measured. In addition, expressions of phospholipid hydroperoxide glutathione peroxidase (GPx4) genes (gpx4a and gpx4b) were analyzed. Lipid peroxidation was followed by the determination the amount of conjugated dienes (CDs) and -trienes (CTs) and malondialdehyde (MDA). Short-term exposure showed that both of the investigated mycotoxins caused rapid changes in the lipid peroxidation processes in the hepatopancreas, but the emerging free radical burden quickly activated the glutathione redox system, so the end-product of the lipid peroxidation (MDA) did not elevate significantly in the 24-hour period. Expression of the genes decreased after 8 hours and later increased during the 24-hour period. As effect of long-term exposure, the glutathione redox system showed decreased levels in T-2 toxin treated group, but the markers of lipid peroxidation processes did not elevate. Expression of the investigated genes showed dual response during the experiment. The results revealed that glutathione redox system eliminated effectively the peroxidative effect of the investigated mycotoxins in the applied doses and periods.