The effect of oral Zn treatment was studied in the liver and kidneys of 26 male Long-Evans Cinnamon (LEC) rats (mutant animals, 5 weeks old) in relation to both the interaction between Zn and Cu and the localisation and concentration of metallothionein (MT). Rats receiving 80 mg zinc acetate daily by gavage and control rats receiving no treatment were killed after 1 or 2 weeks. By immunohistochemical and analytical chemical techniques we revealed that treated rats had higher levels of MT in the hepatic and renal cells compared to untreated ones. Tissue Zn concentrations were significantly higher in treated rats compared to untreated whereas Cu concentrations decreased in the liver and kidneys as indicated by analytical chemical analyses. MT levels also decreased with treatment period. A histochemical procedure, obtained using autofluorescence of Cu-metallothioneins, confirms these findings: after 2 weeks, the signal decreased in both the liver and kidney sections. This gives a greater understanding of the mechanism of Cu metabolism in the two tissues considered. These results suggest that Zn acts both to compete for absorption on the luminal side of the intestinal epithelium and to induce the synthesis of MT.
The Long-Evans Cinnamon (LEC) rat is a mutant animal model for Wilson's disease. It is known that an abnormal accumulation of Cu and Fe in the liver and low concentrations of both ceruloplasmin and Cu in the serum occur in these rats. The accumulation of Cu is explained by the defective expression of the Cu-transporting P-type ATPase gene, homologous to the gene for Wilson's disease (ATP7B). The aim of this work was to clarify the action mechanism of Zn, and to verify the role that this metal plays in LEC rats in short-term treatment experiments (1 and 2 weeks) on concentrations of Cu, Zn, Fe, metallothionein (MT), 8-hydroxy-2'-deoxyguanosine (oh(8)dG) and on the activity of antioxidant enzymes. It is well known that Zn induces MT and has the ability to prevent redox-active metals, Cu and Fe, binding to and causing oxidative damage at active sites of Zn metalloenzymes and nonspecific binding sites on proteins. Zn administration reduces Cu and Fe transport from mucosal to serosal intestinal sides through competitive mechanisms. Our findings show that treatment with zinc acetate increases tissue Zn and MT contents and decreases Cu and Fe concentrations in the liver and kidneys, even if hepatic Zn and MT concentrations decrease with treatment period. Induction of MT synthesis by Zn contributes to the reduction in free radicals produced by Cu and Fe. We also observed that the superoxide dismutase (SOD)activity in liver decreases with treatment duration in association with the Cu and Fe liver decrease. However, the SOD activity in kidney increases in untreated rats at 2 weeks relative to those untreated for 1 week.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.