Age dependent changes in metallothionein and accumulation of cadmium in horses.

This research article discusses the study of how levels of cadmium, zinc, and metallothionein, a protein, change in the livers and kidneys of horses as they age. It also looks at how these variations connect with the presence of these elements and compounds in different parts of the horse’s cell structures.

Analysis of Tissue Samples

• The study involved the examination of liver and kidney tissues from 28 horses. In each sample, the researchers looked for the presence of three main elements: cadmium, zinc, and a protein called metallothionein.
• The study observed a relatively low concentration of cadmium in the liver tissues of the horses. This is contrasted with a gradual increase of cadmium content observed in the kidneys as the horses age, indicating that cadmium accumulates in the kidneys over time.

Relationship between Metallothionein, Zinc and Cadmium

• It was determined that the amount of metallothionein – a protein capable of binding with heavy metals and known for its role in metal detoxification – varied in correlation with the zinc and cadmium content in the tissues.
• In the liver, the metallothionein values fluctuated depending on the zinc content. In the kidneys, the amount of metallothionein varied with the cadmium content. This suggests that the levels of metallothionein in these different organs might be linked to their respective heavy metal content.
• In contrast, the copper values in the liver and kidney tissues seemed to remain stable, showing no significant variations.

Localization of Metallothionein

• The researchers used a technique called immunohistochemistry to determine where in the cells of the liver and kidneys the metallothionein was located.
• The results showed that the metallothionein was mostly found in the cytoplasm of the cells in both organs. The cytoplasm is the cell component where metabolism occurs and it’s involved in the detoxification of harmful substances, which could possibly suggest the metallothionein’s role in neutralizing the effects of heavy metals.