Although information on the effects of Cr6+ in biological systems is abundant, Cr3+ has received less attention. Toxic effects of chromium compounds are partially associated with activation of redox processes. Recently we found that Cr6+ induced oxidative stress in goldfish tissues and the glutathione system was shown to play a protective role. The present study aimed to investigate free radical processes in brain of goldfish exposed to CrCl3. Trivalent chromium at a concentration of 50 mg L-1 was lethal and therefore we chose to examine sublethal dosages of 1.0-10.0 mg L-1 in aquarium water. The levels of lipid peroxides and protein carbonyls (measures of oxidative damage to lipids and proteins) in brain increased after 96 h exposure of goldfish to Cr3+. However, exposure to 1.0-10.0 mg L-1 Cr3+ decreased total glutathione concentration in brain by ∼50-60%. Oxidized glutathione levels also fell by ∼40-60% except at the 10.0 mg L-1 dosage where they decreased by 85%. Therefore, 10.0 mg L-1 Cr3+ significantly reduced the ratio [GSSG]/[totalGSH] to 35% of the control value. Chromium treatment did not affect the activity of superoxide dismutase, but reduced the activities of catalase by 55-62% and glutathione-S-transferase by 14-21%. The activities of glucose-6-phosphate dehydrogenase and glutathione reductase were unchanged under any experimental conditions used. Therefore, it can be concluded that although Cr3+ exposure induced oxidative stress in goldfish brain, it failed to enhance the efficiency of the antioxidant system in the organ.

Antioxidant enzymes, Glutathione, Lipid peroxides, Oxidative stress, Protein carbonyls
Department of Biology

Lushchak, O.V. (Oleh V.), Kubrak, O.I. (Olha I.), Torous, I.M. (Ihor M.), Nazarchuk, T.Yu. (Tetyana Yu.), Storey, K, & Lushchak, V.I. (Volodymyr I.). (2009). Trivalent chromium induces oxidative stress in goldfish brain. Chemosphere, 75(1), 56–62. doi:10.1016/j.chemosphere.2008.11.052