Proteomic profiling reveals the differential toxic responses of gills of common carp exposed to nanosilver and silver nitrate.

Although the toxic effects of silver nanoparticles (AgNPs) on fish gills have been reported, the underlying mechanism of toxicity remains unclear. The present study aimed to elucidate the mechanism of toxicity in the gills of common carp following exposure to AgNPs and silver nitrate (AgNO3) using histopathology and proteomics. Histopathological findings revealed that both AgNPs and AgNO3 caused telangiectasia and epithelial cell hyperplasia in fish gills; however, the pathological features and location of lesions caused by the two forms of silver were markedly different. Proteomics revealed that AgNPs and AgNO3 induced 139 and 185 differential expression proteins (DEPs) in gills, respectively, and the two forms of silver induced only 42 shared proteins. AgNPs specifically induced 87 DEPs which mainly involved signaling mechanisms, cytoskeleton, and the arachidonic acid metabolism processes. AgNO3 specifically induced 125 DEPs that were mainly clustered in the glutathione metabolism and protease processes. These results suggested that the toxic effects of AgNPs and AgNO3 were dramatically different in terms of protein expression in fish gills, which may provide novel perspectives for understanding the toxicity mechanism of silver nanoparticles in fish gills.