Metal-ion-mediated oxidative stress in the gill homogenate of rainbow trout (Oncorhynchus mykiss) |
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Authors: | M Arabi M A Alaeddini |
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Institution: | (1) Faculty of Basic Sciences, Department of Biology, Toxicology Unit, Shahrekord University, 88186 Shahrekord, Iran;(2) Faculty of Art Sciences, Shahrekord University, 88186 Shahrekord, Iran |
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Abstract: | Human activities play a major role in toxic and carcinogenic metal pollution of the environment. This study was undertaken
to evaluate the effects of copper and mercury at the 400-to 1000-μM concentration range on some biochemical markers of oxidative
stress, such as lipid peroxidation (LPO), glutathione-S-transferase (GST) activity, and reduced glutathione (GSH) content
in the rainbow trout gill homogenates with or without supplementation of manganese, selenium, and bovine serum albumin (BSA).
The integrity of DNA was also measured to assess metal ion toxicity. The results showed that the LPO and specific activity
of GST were elevated. This indicated that cell-protecting antioxidant mechanisms were overtaxed and could not prevent membrane
peroxidation. Following the addition of metals, the GSH content was also significantly reduced in a concentration-dependent
manner. Mercury was found to be more effective than copper. The application of antioxidants proved beneficial in inhibiting
LPO, reducing GST activity, and elevating the GSH levels in the gill samples. Manganese was more effective than selenium and
BSA. Surprisingly, when BSA (1.0%) was added to the gill homogenates treated with a 1000-μM concentration of metal ions, instead
of alleviating malondialdehyde (MDA) generation, a drastic elevation in the MDA levels, alleviation in GST activity, and a
further decrease in glutathione (GSH) levels were observed, which were most likely the result of pro-oxidant activity of BSA.
The results also indicated that mercury and copper functioned as genotoxic pollutants, which altered the DNA integrity by
inducing the single and double-stranded DNA breaks in the gill cell nuclei. Collectively, toxicity of metal ions is related
to the depletion of GSH content and inhibition of antioxidant enzyme GST, resulting in the propagation of LPO and DNA damage. |
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Keywords: | Metal ion rainbow trout peroxidation manganese selenium BSA |
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