Ultrastructural and biochemical changes in the turkeys liver after the chronic cadmium exposure

Abstract

The aim of our study was to observe the chronic effects of cadmium and cadmium with zinc on the structure and histological changes in turkey liver by means of transmission electron microscopy and to examine whether concentrations of metals influence the activity of superoxide dismutase and lipid peroxidation in liver tissue. The ultrastructural changes were investigated in hepatocytes after 71 days exposure to cadmium (Cd group) and cadmium + zinc (Cd/Zn group). In Cd group, ultrastructural changes included swollen and round mitochondria with injured cristae, dilated rough endoplasmatic reticulum and depletion of glycogen granules. In the Cd/Zn group hepatocytes showed morphological features similar to those from the control group except the mitochondria. They had an oval or elliptical shape similar as in the control group, but the cristae were obviously loose and dissolved. The activity of superoxide dismutase (SOD) and the content of thiobarbituric acid reactive substances (TBARS) were determined. The specific activity of SOD was significantly increased in Cd group. In Cd/Zn group, zinc co-administration shows a protective effect. Alterations in the activitiy of superoxide dismutase showed that the toxic effect of cadmium is not only due to its high affinity for thiol groups, but also in the production of reactive oxygen species. Cadmium induced ultrastructural changes in the hepatocytes were not accompanied by a significant increase in tissue TBARS concentrations.