Ultrastructural and immunohistochemical investigation on the gills of the teleost, Thalassoma pavo L., exposed to cadmium

An investigation was conducted to determine the effects of the heavy metal, cadmium (Cd), on the gills of the teleost fish, Thalassoma pavo Linnaeus, 1758. The fishes were exposed to several sublethal concentrations of cadmium (10, 40, 60 and 120 mM (mg/L)) for a period of 48, 96 and 192h. The value ofthe LC50 after 96h of cadmium exposure, determined using the System of Finney, was equal to128.3 mM. The gills of the fishes were examined by light and electron microscopy. Toxic, apoptotic and cadmium effects were analyzed using some neuropeptides, metallothioneins (MT), caspase3, PCNA and calmodulin, as bioindicators, respectively.The results showed that the alterations in the gills were proportional to the exposure periods and concentrations of the metal, which were found to be both dose and time dependent. The biological responses in the gills of the tested animals are discussed in relation to results obtained by analysis of the biomarkers. These data may be used for the planning of a model to determine biological risk in the marine environment and may be particularly useful to investigate organisms exposed to cadmium.