Carp erythrocyte lipids as a potential target for the toxic action of zinc ions.

The effects of zinc on the lipid components of carp erythrocytes (Cyprinus carpio L.) were studied on red blood cells exposed to ZnSO4 (0.01-1 mM) for 20 h. The temperatures of the incubation medium were 5 and 20 degrees C for carp collected in winter and summer, respectively. It was observed that increase in the concentration of metal ions in the medium led to significant changes in the content of the main phospholipid classes. Zinc induced the reduction of phosphatidylcholine as well as the increase in the content of phosphatidylserine and phosphatidylinositol. A marked increase in the levels of malondialdehyde and conjugated dienes was also found both in the cells and the incubation medium. Moreover, elevated Zn concentrations caused alterations in the erythrocyte plasma membrane fluidity, estimated by measuring the fluorescence of 1-[4-trimethylaminophenyl]-6-phenyl-1,3,5-hexatriene and 12-[9-anthroyloxy]stearic acid, located on the surface and in the hydrophobic regions of the lipid bilayer. This study in vitro confirmed that higher concentrations of zinc ions induce marked changes in the composition and structure of membrane lipids in carp erythrocytes.