Relationship between metallothionine and zinc in the protection against DNA damage in zinc-treated Long-Evans Cinnamon rat liver

• Published in: European journal of histochemistry Vol. 48; no. 3; pp. 317 - 320
• Main Authors: Santon, A, Albergoni, V, Santovito, G, Sturniolo, G C, Irato, P
• Format: Journal Article
• Language: English
• Published: Italy PAGEPress Publications 01.07.2004
• Subjects: Animals; Apoptosis - drug effects; Cell Count; Disease Models, Animal; DNA Damage - drug effects; Dose-Response Relationship, Drug; Hepatolenticular Degeneration - drug therapy; Hepatolenticular Degeneration - metabolism; Hepatolenticular Degeneration - pathology; Immunohistochemistry; In Situ Nick-End Labeling; Liver - drug effects; Liver - metabolism; Liver - pathology; Male; Metallothionein - drug effects; Metallothionein - metabolism; Oxidative Stress - drug effects; Rats; Rats, Inbred LEC; Time; Zinc - therapeutic use
• ISSN: 1121-760X; 2038-8306

The aims of the work presented here were to determine the effect of long term treatment with zinc (Zn) on both total metallothionine (MT) and, in particular, oxidized MT (MTox) concentrations in Long-Evans Cinnamon (LEC) rat liver. We also evaluated semi-quantitatively the cell death index using TUNEL assay as it is a useful method to localize the nuclear fragmentation occurring in oxidative stress conditions. The results demonstrate there were no statistically different MT concentrations between Zn-treated and untreated rats, whereas the Zn treatment was very effective in reducing the percentage of oxidized MT (MTox). MTox is not able to bind metals, so it does not perform its "scavenger" action against copper (Cu) accumulation in LEC rats. The intensity and quantity of fluorescent staining observed in untreated rat sections decreased compared to the treated ones. These findings suggest that in LEC rats one of zinc's roles is to protect from oxidative stress, however, its mode of action remains partially unknown: a hypothesis is competition for Cu binding sites. A new insight is that Zn induced MT can protect efficiently against DNA damage by free radicals.