Toxic effects of diclofenac on gills, liver and kidney of Cyprinus carpio (Linnaeus, 1758)

Diclofenac, the anti-inflammatory drug, is found in natural water bodies all over the world. Toxicological researches of diclofenac report harmful effects on aquatic species even at low concentrations. The aim of the present study is to determine whether diclofenac affects the gills, livers and kidneys of common carp (Cyprinus carpio). In order to evaluate the toxic effects of diclofenac as NASIDs in fish, common carps (Cyprinus carpio) were exposed to diclofenac concentrations of 1.25 mg/L, 2.5 mg/L and 5 mg/L. Over a 21-day experiment period, diclofenac effects on the fishes were investigated by weekly histopathological observations. The histopathological examinations of diclofenac on the exposed fishes revealed alterations of the kidneys pertaining to hyaline droplet, increase in interstitial cells, shrinkage of glomeruli, and the presence of melanomacrophages and necrosis of epithelial cells of tubules. In the gills, the predominant finding consisted of epithelial hyperplasia, telangiectasia, clubbing, lamellar fusion, and increase of mucosal cells. Histopathological alterations were also observed in the liver, including the presence of melanomacrophages, degeneration, vacuolation of hepatocytes, and necrosis. Comparatively, the most alterations were found in the gills and the liver. On the contrary, the gills, livers and kidney sections of two control groups exhibited normal architecture. The study’s results revealed that diclofenac could be harmful for Cyprinus carpio (as  one of the main species in Caspian Sea).