Trivalent chromium induces oxidative stress in goldfish brain.
Although information on the effects of Cr(6+) in biological systems is abundant, Cr(3+) has received less attention. Toxic effects of chromium compounds are partially associated with activation of redox processes. Recently we found that Cr(6+) 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 CrCl(3). 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 Cr(3+). However, exposure to 1.0-10.0 mg L(-1) Cr(3+) decreased total glutathione concentration in brain by approximately 50-60%. Oxidized glutathione levels also fell by approximately 40-60% except at the 10.0 mg L(-1) dosage where they decreased by 85%. Therefore, 10.0 mg L(-1) Cr(3+) 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 Cr(3+) exposure induced oxidative stress in goldfish brain, it failed to enhance the efficiency of the antioxidant system in the organ.
Lushchak
Oleh V
OV
Department of Biochemistry, Precarpathian National University named after Vassyl Stefanyk, 57 Shevchenko Str., Ivano-Frankivsk, 76025, Ukraine.
Kubrak
Olha I
OI
Torous
Ihor M
IM
Nazarchuk
Tetyana Yu
TY
Storey
Kenneth B
KB
Lushchak
Volodymyr I
VI
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002374:Catalase / Q000378:metabolism; D002857:Chromium / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity*; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D006054:Goldfish / Q000378:metabolism*; D015227:Lipid Peroxidation; D018384:Oxidative Stress / Q000187:drug effects*
D002857:Chromium; D002374:Catalase; D005978:Glutathione; D019803:Glutathione Disulfide