Effect of exogenous copper on lipid peroxidation in rat hepatocytes. Possible involvement of protein kinase C

The Protective Roles of Selenium on Hepatic Tissue Ultrastructure and Mitochondrial Antioxidant Capacity in Copper-Overloaded Rats

The aim of this study was to explore the effects of selenium addition on hepatic tissue ultrastructure and mitochondrial antioxidant capacity in copper-overloaded rats. Eighteen adult male Sprague-Dawley (SD) rats were randomly divided into three groups (n = 6 per group). Each group received 1 mL (intragastrically) of water (control, group I) or water containing copper chloride (CuCl2, 1 mol/L) (group II) or a mixture of CuCl2 (1 mol/L) with sodium selenite (Na2SeO3, 0.05 mol/L) (group III) once daily for 30 days. Histological examination revealed normal hepatocyte structure and no ultrastructural changes in mitochondria in controls. In contrast, group II exhibited severe ultrastructural alterations, fuzzy mitochondrial membranes, irregularly shaped and fragmented rough endoplasmic reticulum (RER), and the high melanin content; group III also exhibited larger amounts of engulfing vesicles (EV) in the cytoplasm. Compared to controls, the CuCl2 treatment lowered (P < 0.05) hepatocyte enzymatic activities and increased lipid peroxidation as indicated by an increase in malondialdehyde (MDA) levels. The effects of CuCl2 were attenuated by simultaneous administration with Na2SeO3. These results indicated that the adverse effects of copper toxicity can be partially attenuated by providing a source of selenium.

The effects of copper sulfate on liver histology and biochemical parameters of term Ross broiler chicks

Copper is an essential trace element that is extremely toxic to organisms and organs at high doses. We have investigated the histological and biochemical effects of a toxic dose of copper sulfate on the liver of term Ross broiler chicks. Fertilized eggs were divided into three groups: experimental, injected with 50 mcg/0.1 ml copper sulfate in the air chambers on day 1; sham, injected with 0.1 ml saline; and control, no injection. Term chicks were killed and their livers investigated histologically, with hematoxylin-eosin-stained sections examined under light microscopy, and biochemically, for malondialdehyde and glutathione levels. Histological examinations showed copper-treated samples with granular degeneration and necrosis of hepatocytes and impairment to the cell lining of the remark cords. The samples had a congestive appearance, with blood in the vena centralis and sinusoids, slight connective tissue increase, and lymphocyte infiltration. Control and sham group sections had normal appearances. As oxidative damage parameters, in the copper-treated group, malondialdehyde levels were increased and glutathione levels decreased. In the sham and control groups, there were no significant differences. At this toxic dose, copper sulfate shows oxidative damage according to the histology of term chick liver that are confirmed biochemically by the changes in malondialdehyde and glutathione levels.

Protein kinase C (PKC)-mediated protein phosphorylation in rat aortic smooth muscle cells is enhanced by allylamine

The profile of endogenous protein phosphorylation mediated by protein kinase C (PKC) was examined in cell fractions prepared from subcultured aortic smooth muscle cells (SMCs) isolated from rats treated with 70 mg/kg allylamine (AAM) or tap water for 20 days. Increased phosphorylation of endogenous proteins was observed under unstimulated conditions in the particulate, but not cytosolic, fraction of cells from AAM-treated animals (i.e. AAM cells) relative to control cells. Although the same phosphorylation bands were observed in the particulate or cytosolic fraction of control and AAM cells following phorbol ester stimulation of the enzyme, enhanced PKC-mediated phosphorylation was observed in both fractions of AAM cells relative to control cells. Measurements of exogenous histone Type III-S phosphorylation by PKC following in vitro exposure of naive SMCs to 100 microM AAM for up to 60 min revealed that AAM selectively increased histone phosphorylation in the cytosolic fraction of SMCs. These results demonstrate that AAM treatment enhances PKC-mediated protein phosphorylation in rat aortic SMCs and raise the possibility that such alterations participate in the angiotoxic response to AAM.