Genotoxic and antigenotoxic properties of selenium compounds in thein vitromicronucleus assay with human whole blood lymphocytes and tk6 lymphoblastoid cells

Eduard Cemeli,Ricard Marcos,Diana Anderson

doi:10.1100/tsw.2006.204

Eduard Cemeli, Ricard Marcos + Show 1 more

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https://doi.org/10.1100/tsw.2006.204

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Abstract

Selenium is known to possess both genotoxic and antigenotoxic properties. In the present study, we have evaluated the genotoxicity and antigenotoxicity of three selenium compounds (sodium selenate, sodium selenite and selenous acid) by measuring in vitro micronucleus induction. Assays were conducted in whole blood lymphocytes and in the TK6 lymphoblastoid cell line, with and without co-treatment with potassium dichromate, a known genotoxic compound. In general, the compounds were more active in TK6 cells than they were in blood lymphocytes. Only 1 μM selenous acid increased the frequency of binucleated cells containing micronuclei (BNMN) in blood lymphocytes, while all three selenium compounds increased BNMN in TK6 cells. In addition, combinations of selenous acid and potassium dichromate resulted in lower frequencies of BNMN than potassium dichromate alone in blood lymphocytes, while combinations of sodium selenate and potassium dichromate produced lower frequencies of BNMN than potassium dichromate alone in TK6 cells. The concentrations of selenium compounds that were used, in combination with the medium components and the biological physiology of the whole blood lymphocytes and TK6 cells, could have affected the redox potential of the compounds, switching the chemicals from a pro-oxidant to antioxidant status and vice-versa. The lower activities of the compounds in blood lymphocytes may be due to the protective effects of blood components. The results indicate that the genotoxic and antigenotoxic properties of selenium compounds are highly dependent upon the conditions under which they are evaluated.

Highlights

Since the toxicity of selenium was first described in 1933 in the U.S.[1], there has been controversy regarding the genotoxic and antigenotoxic properties of this metal
This study demonstrated that sodium selenite had no effect on the genetic damage induced by chromium in TK6 human lymphoblastoid cells[18]
We have studied whether three selenium compounds affected the cytotoxicity and genotoxicity of potassium dichromate by measuring micronucleus induction in whole human blood lymphocytes and in the TK6 lymphoblastoid cell line

Summary

Introduction

Since the toxicity of selenium was first described in 1933 in the U.S.[1], there has been controversy regarding the genotoxic and antigenotoxic properties of this metal. Concentrations of selenium in plasma and whole blood provide useful indicators of human selenium intake and status. The mean reference value of selenium in plasma from healthy individuals in the metropolitan area of Barcelona (Spain) obtained was 82.2 ± 17.5 μg/l[9], whereas in Upper Silesia (Poland), it was 62.5 ± 18.4 μg/l, which is below the lower limit of the nutritional adequacy range [80 μg/l][10]. Long-term selenosis was apparent in five patients with blood selenium concentrations in excess of 1.054–1.854 mg/l. This concentration was estimated to represent a selenium intake of 0.91 mg/day. This value is arguable since the reduction of intake reverses the effects of selenosis[13]

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