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Effects of selenium on toxicity and ultrastructural localization of mercury in cultured murine macrophages
M Christensen1, J Rungby, S C Mogensen
1Department of Neurobiology, University of Aarhus, Denmark.
Abstract:
The effects of selenium on cellular toxicity and histochemical distribution of mercury were examined in a cell culture system of mouse peritoneal macrophages. Selenium protected against the toxicity of mercury in cultures exposed to 4 microM of mercuric chloride. Selenomethionine caused a significant increase in cell survival throughout the experiments, while sodium selenite delayed the toxicity of mercury for a while, after which selenite itself had a toxic effect. The amount of mercury visualized by autometallography was increased in macrophage cultures pre-exposed to sodium selenite or selenomethionine. The additional mercury made visible by this histochemical demonstration was located in the cytoplasm as well as in the lysosomes.
Insights
Selenium compounds protect mouse macrophages from mercury toxicity. Selenium increased mercury accumulation in cells, particularly in lysosomes, suggesting a mechanism for detoxification and cellular protection against heavy metal poisoning.
Area of Science:
- Cell Biology
- Toxicology
- Biochemistry
Background:
- Mercury (Hg) is a toxic heavy metal.
- Selenium (Se) is known to counteract mercury toxicity.
- Understanding the interaction between Se and Hg at the cellular level is crucial for toxicology.
Purpose of the Study:
- To investigate the protective effects of selenium on mercury-induced cellular toxicity.
- To examine the histochemical distribution of mercury in macrophages exposed to selenium.
- To compare the effects of different selenium compounds (selenomethionine and sodium selenite) on mercury toxicity and distribution.
Main Methods:
- Primary cell culture of mouse peritoneal macrophages.
- Exposure to mercuric chloride (HgCl2) with or without selenium compounds.
- Assessment of cell survival and toxicity.
- Histochemical visualization of mercury using autometallography.
Main Results:
- Selenium compounds, particularly selenomethionine, significantly protected macrophages against mercury toxicity.
- Sodium selenite offered temporary protection but became toxic at later stages.
- Selenium pre-exposure increased the amount of visualized mercury within macrophages.
- Accumulated mercury was localized in the cytoplasm and lysosomes.
Conclusions:
- Selenium compounds can mitigate mercury's cellular toxicity in macrophages.
- Selenium enhances mercury accumulation within cells, potentially sequestering it in lysosomes.
- These findings provide insights into the cellular mechanisms of selenium's protective role against mercury poisoning.