Cadmium Accumulation and Antioxidant Responses in Sparus aurata Exposed to Waterborne Cadmium
Cadmium (Cd), a nonessential trace element, is rapidly accumulated by most living organisms and subsequently exerts its toxicity at different molecular levels. This study exposed gilthead sea bream (Sparus aurata) to waterborne 0.1 mg/l Cd for 11 days and investigated the Cd accumulation pattern, lipid oxidation, and response of antioxidant defences. At the end of the experiment, mean Cd concentrations in gills and liver, the organs most prone to metal accumulation, were 209.4 and 371.7 ng/g ww, respectively. Muscle did not show any Cd retention during the 11 days of exposure. In liver, the cytosolic fraction of the metal was chelated into the nontoxic form by metallothionein (MT), a specific Cd-inducible protein. Zn and Cu concentrations were not influenced by Cd exposure. Glutathione (GSH) concentrations and the antioxidant enzyme activities of GSH reductase and GSH peroxidase showed an overall decreasing trend. In addition, lipid and aqueous hydroperoxide levels did not show any significant variation. Oxidative stress indirectly generated by Cd seems to be compensated for by the different biochemical systems tailored to decrease cellular damage. In particular, the negative effects of Cd accumulation in tissues were probably counteracted by the induction of MT.
KeywordsGSSG Lipid Hydroperoxide Xylenol Orange Provisional Tolerable Weekly Intake Exposed Fish
This project was funded by a grant from MIUR (Grant No. 2005073277_001) to E. C.
- Carpenè E, Vašàk M (1989) Hepatic metallothioneins from goldfish (Carassius auratus L). Comp Biochem Physiol C Toxicol Pharmacol 92:463–468Google Scholar
- Carpenè E, Camatti A, Isani G, Cattani O, Cortesi P (1992) Cd-metallothionein in liver and kidney of goldfish (Carassius auratus): effects of temperature and salinity. Ital J Biochem 41:273–282Google Scholar
- Cattani O, Serra R, Isani G, Raggi G, Cortesi P, Carpenè E (1996) Correlation between metallothionein and energy metabolism in sea bass Dicentrarchus labrax exposed to cadmium. Comp Biochem Physiol C Toxicol Pharmacol 113:193–199Google Scholar
- Food and Agriculture Organization of the United Nations (2008) Fisheries and Aquaculture Department. http://www.fao.org/fishery/sofia/en. Accessed 2 Apr 2008
- Food and Agriculture Organization/World Health Organization (1972) Evaluation of certain food additives and the contaminants mercury, cadmium and lead. WHO Technical Report Series No. 505, Geneva, SwitzerlandGoogle Scholar
- Isani G, Andreani G, Monari M, Carpenè E (2003) Metal concentrations (Cu, Zn and Cd) and metallothionein expression in Sparus aurata exposed to waterborne copper. J Trace Elem Med Biol 17:17–23Google Scholar
- Kamunde C, MacPhail R (2011) Metal-metal interactions of dietary cadmium, copper and zinc in rainbow trout, Oncorhynchus mykiss. Ecotoxicol Environ Saf (in press)Google Scholar
- Minghetti M, Leaver MJ, Carpenè E, George SG (2008) Copper transporter 1, metallothionein and glutathione reductase genes are differentially expressed in tissues of sea bream (Sparus aurata) after exposure to dietary or waterborne copper. Comp Biochem Physiol C Toxicol Pharmacol 147:450–459CrossRefGoogle Scholar
- Webb M (1987) Toxicological significance of metallothionein. In: Kägi JHR, Kojima Y (eds) Metallothionein II. Birkhauser Verlag, Basel, GermanyGoogle Scholar