Effect of sub lethal concentrations of silver nanoparticles and silver nitrate on HSP70 gene expression and gill, liver and intestinal damage in common carp (Cyprinus carpio L.)

In this study, to investigate the effects of silver on juvenile common carp (Cyprinus carpio), the fish were exposed to sub-lethal concentrations of silver-nanoparticles and silver nitrate. For this purpose, at first, Lethal Concentration (LC50-96 h) for two silver forms was obtained and then fish were exposed to sub-lethal concentrations (0.04 and 0.08 mg/L for silver NPs and 0.025 and 0.025 mg/L for silver nitrate) for 21 days and desired indicators were measured. After exposure to silver, various lesions have been observed in the tissues, that most important of these are the following: epithelial lifting, shorting and collapse of secondary lamellae in gills, nucleus degradation and necrosis and hypertrophy of hepatocytes in the liver and also destruction of the structure of intestinal villi. Results of this study showed that long exposure with silver NPs, caused significantly increase Hsp70 gene expression and after exposure of common carp with silver nitrate, Hsp70 greatly increased however, in term of gene expression, there was no difference between two genes. Also, the most effects observed among the tissues studied in this study were observed in the liver of fish exposed to two forms of silver and at the highest concentration and there was no difference between the two forms of silver in term of toxicology.