Oxidative stress in liver of brown bullhead and channel catfish following exposure to tert-butyl hydroperoxide

Abstract

Reactive oxygen species (ROS) have been implicated in the etiology of liver neoplasia in mammals and fishes. Oxidation of DNA and lipid peroxidation may be important early markers of such damage in certain species and tissues. In this study, 8-hydroxy-2′-deoxyguanosine (8-OHdG) was measured in channel catfish ( Ictalurus punctatus) and brown bullhead ( Ameriurus nebulosus) liver after glutathione (GSH) depletion (with diethyl maleate/buthionine sulfoximine injection) and exposure to the exogenous oxidant, tert-butyl hydroperoxide ( t-BOOH). GSH depletion alone resulted in a significant increase in lipid peroxidation in hepatic tissue of brown bullhead, but not in channel catfish. GSH depletion alone did not result in a significant increase in 8-OHdG formation as assessed by high performance liquid chromatography and electrochemical detection in either species. Treatment with t-BOOH alone or in combination with GSH depletion did not affect levels of DNA oxidation in either species. These results suggest that liver cells from these species of fish are relatively insensitive to the formation of oxidative DNA damage following exposure to a severe oxidative stress, and that lipid peroxidation may be a more appropriate early marker of oxidative stress in liver of these species.