Zinc-induced damage to carp (Cyprinus carpio L.) erythrocytes in vitro

Fish erythrocytes were used to elucidate the effect of zinc ions on the cel l antioxidant defence system. It was detected that an increase of the Zn2concentration (0.01-1 mM) leads to a marked decrease (p < 0.05) in the cata lase and the glutathione peroxidase activities. We observed a loss of 14-39 % activity of glutathione peroxidase, and 16-20 % diminution for catalase. No significant changes were found in case of the superoxide dismutase. Inc ubation of red blood cells with zinc brought about a decrease of the erythr ocyte thiol group content. Treatment of carp erythrocytes with zinc ions al so resulted in enhanced hemolysis and in the induction of significant (p < 0.001) changes in the intracellular glucose level. The increase of glucose concentration in the erythrocytes was correlated with increased concentrati on of metal in the incubation medium. It was proposed that Zn could affect transport systems across the red blood cells and therefore increased the pe rmeability of the membranes to small molecules (e.g, hexose), and led to he molysis. Zinc ions could act as a potential cell toxicant, leading to distu rbances in functions of the antioxidant defence system and to alterations i n the erythrocyte membrane properties.