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Banni M.,Laboratoire Of Biochimie Et Toxicologie Of Lenvironnement Ur04Agr05 | Chouchene L.,Institute Superieure Of Biotechnologie Of Monastir | Said K.,Institute Superieure Of Biotechnologie Of Monastir | Kerkeni A.,University of Monastir | Messaoudi I.,Institute Superieure Of Biotechnologie Of Monastir
BioMetals | Year: 2011

The present study was designed to elucidate the protective effect mechanism of Zinc (Zn) and Selenium (Se) on cadmium (Cd)-induced oxidative stress in zebrafish. For this purpose we investigate the response of oxidative stress markers, metallothionein accumulation and gene expression in liver and ovary of female zebrafish exposed to 0,4 mg/l Cd in water and supplemented with Zn (5 mg kg -1) and/or Se (2 mg kg -1) for 21 days in their diet. Liver and ovary Cd uptake was evaluated after the exposure period. Cd exposure significantly inhibited the antioxidant enzyme activities termed as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxydase (GPx) and caused a pronounced malondialdehyde (MDA) accumulation in both organs. Co-administration of Zn and Se reversed the Cd-induced toxicity in liver and ovary measured as MDA accumulation. Interestingly, gene expression patterns of Cat, CuZnSod and Gpx were up-regulated when related enzymatic activities were altered. Zebrafish metallothionein transcripts (zMt) significantly decreased in tissues of fish supplemented with Zn and/or Se when compared to Cd-exposed fish. Our data would suggest that Zn and Se protective mechanism against Cd-induced oxidative stress is more depending on the correction of the proteins biological activities rather than on the transcriptional level of related genes. © 2011 Springer Science+Business Media, LLC.

Messaoudi I.,Institute Superieure Of Biotechnologie Of Monastir | Said L.,Institute Superieure Of Biotechnologie Of Monastir | El Heni J.,University of Monastir | Kerkeni A.,University of Monastir | Said K.,Institute Superieure Of Biotechnologie Of Monastir
Archives of Environmental Contamination and Toxicology | Year: 2010

Cadmium (Cd), one of the most widely distributed heavy metals, is highly toxic to humans and animals. It is well known that zinc (Zn) and selenium (Se) administration reduce the Cd-induced toxicity and that metallothioneins can have a protective effect to mitigate Cd toxicity in biological systems. In this study we report the expression analysis of the two metallothioneines gene classes MT-1 and MT-2 as well as the total metalloprotein content in the liver of rats exposed to Cd (200 ppm), Cd + Zn (200 ppm + 500 ppm), Cd + Se (200 ppm + 0.1 ppm) or Cd + Zn + Se (200 ppm + 500 ppm + 0.1 ppm) in their drinking water for 35 days. Metals accumulation was quantified in rat liver. Cd decreased significantly the hepatic concentrations of Se and increased those of Zn. The treatment of Cd-exposed rats with Se alone or combined with Zn reversed the Cd-induced depletion of Se concentrations in the liver. However, Zn or Zn + Se administration significantly increased the liver Cd uptake and had no effect on the Cd-induced increase in hepatic concentrations of Zn. The molecular assay showed a decreasing trend of MT-1 relative gene expression levels in animals supplemented with Zn (6.87-fold), Se (3.58-fold), and their combination (1.69-fold) when compared to Cd-treated animals (16.22-fold). Upregulation of the MT-2 expression were recorded in all conditions, although fold induction levels were less pronounced than MT-1 expressions. Our data suggest that the well-established protective effect of Zn and Se against Cd-induced toxicity passes through non-MT gene expression mechanisms, being more dependent on the oxidative stress status of the cell. © 2010 Springer Science+Business Media, LLC.

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