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Multi-organ histological observations on juvenile senegalese soles exposed to low concentrations of waterborne cadmium

Publication . Costa, P. M.; Caeiro, Sandra; Costa, Maria Helena

A histopathological screening was performed on juvenile Senegalese soles exposed to environmentally realistic concentrations of waterborne Cd (0.5, 5 and 10 lg L-1 ) for 28 days. The severity and dissemination of histopathological changes were variable and limited to the kidney, liver, spleen, gills and skin goblet cells. Contradicting available literature that refers the liver as the most affected organ upon acute exposure and the kidney following chronic exposure, the liver was the most impacted organ (even at the lowest concentration), in a trend that could relate to the duration of exposure and Cd concentration. The most noticeable hepatic alterations related to inflammation, although hepatocellular alterations like lipidosis and eosinophilic foci also occurred. The trunk kidney of exposed fish endured moderate inflammation, apoptosis and necrosis, however, without a clear time-dependent effect. The spleen of fish subjected to the highest concentrations revealed diffuse necrotic foci accompanied by melanomacrophage intrusion. The gills, albeit the most important apical uptake organ of dissolved toxicants, sustained only moderate damage, from epithelial hyperplasia and pavement cell detachment to the potentially more severe chloride cell alterations. In the skin, an increase in goblet cell size occurred, most notoriously correlated to Cd concentration at earlier stages of exposure. The results show that a metal-naı¨ve juvenile fish can endure deleterious effects when exposed to low, ecologically relevant, concentrations of a common toxic metal and that the pattern of Cdinduced histopathological alterations can be complex and linked to organ-specific responses and metal translocation within the organism.

2012-07-01Journal article

Open access

Hepatic proteome changes in solea senegalensis exposed to contaminated estuarine sediments: a laboratory and in situ survey

Publication . Costa, Pedro M.; Chicano-Gálvez, Eduardo; Caeiro, Sandra; Lobo, Jorge; Martins, Marta; Ferreira, Ana M.; Caetano, Miguel; Vale, Carlos; Alhama-Carmona, José; Lopez-Barea, Juan; DelValls, T. Ángel; Costa, Maria Helena

Assessing toxicity of contaminated estuarine sediments poses a challenge to ecotoxicologists due to the complex geochemical nature of sediments and to the combination of multiple classes of toxicants. Juvenile Senegalese soles were exposed for 14 days in the laboratory and in situ (field) to sediments from three sites (a reference plus two contaminated) of a Portuguese estuary. Sediment characterization confirmed the combination of metals, polycyclic aromatic hydrocarbons and organochlorines in the two contaminated sediments. Changes in liver cytosolic protein regulation patterns were determined by a combination of two-dimensional electrophoresis with de novo sequencing by tandem mass spectrometry. From the forty-one cytosolic proteins found to be deregulated, nineteen were able to be identified, taking part in multiple cellular processes such as anti-oxidative defence, energy production, proteolysis and contaminant catabolism (especially oxidoreductase enzymes). Besides a clear distinction between animals exposed to the reference and contaminated sediments, differences were also observed between laboratory- and in situ-tested fish. Soles exposed in the laboratory to the contaminated sediments failed to induce, or even markedly down-regulated, many proteins, with the exception of a peroxiredoxin (an anti-oxidant enzyme) and a few others, when compared to reference fish. In situ exposure to the contaminated sediments revealed significant up-regulation of basal metabolism-related enzymes, comparatively to the reference condition. Down-regulation of basal metabolism enzymes, related to energy production and gene transcription, in fish exposed in the laboratory to the contaminated sediments, may be linked to sedimentbound contaminants and likely compromised the organisms’ ability to deploy adequate responses against insult.

2012Journal article

Open access