Cytological and Biochemical Effects of a Mixture of 20 Pollutants on Isolated Rainbow Trout (Oncorhynchus mykiss) Hepatocytes

Isolated hepatocytes of rainbow trout (Oncorhynchus mykiss) were exposed to different concentrations (1×, 10×, 50×) of a complex mixture of 20 environmentally relevant contaminants (PAHs, PCBs, pesticides) typical of the chemical burden of surface waters and sediments of small rivers in southwest Germany to investigate sublethal cytological and biochemical alterations. Results document that all concentrations clearly induced biochemical and morphological changes. The activities of enzymes such as lactate dehydrogenase and catalase as well as the rate of lipid peroxidation were significantly increased, whereas acid phosphatase activity decreased. Cytopathological effects included deformation of cellular shape, deformation and dilation of the nuclear envelope, increase in heterochromatin, nuclear inclusions, heterogeneity of mitochondria, vesiculation of RER cisternae, as well as increases in myelinated bodies, lysosomes, and peroxisomes. If compared with cytological alterations induced in isolated rainbow trout hepatocytes after exposure to sediment extracts from rivers of corresponding contamination, cytological effects of exposure to the complex chemical mixture displayed numerous similarities.