Blood thioredoxin reductase activity, oxidative stress and hematological parameters in painters and battery workers: relationship with lead and cadmium levels in blood

Authors

  • Greicy M. M. Conterato,

    1. Graduate Program on Toxicological Biochemistry, Center of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, Brazil
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  • Rachel P. Bulcão,

    1. Laboratory of Toxicology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
    2. Graduate Program of Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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  • Rocheli Sobieski,

    1. Integrated Center for Laboratory Analysis Development (NIDAL), Department of Alimentary Technology and Science, Center of Rural Sciences, Federal University of Santa Maria, Santa Maria, Brazil
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  • Angela M. Moro,

    1. Laboratory of Toxicology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
    2. Graduate Program of Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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  • Mariele F. Charão,

    1. Laboratory of Toxicology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
    2. Graduate Program of Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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  • Fernando A. de Freitas,

    1. Laboratory of Toxicology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
    2. Graduate Program of Pharmaceutical Sciences, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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  • Fernanda L. de Almeida,

    1. General Forensic Institute, Porto Alegre, Brazil
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  • Ana P. L. Moreira,

    1. Graduate Program on Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Brazil
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  • Miguel Roehrs,

    1. Graduate Program on Pharmacology, Center of Health Sciences, Federal University of Santa Maria, Brazil
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  • Raquel Tonello,

    1. Graduate Program on Toxicological Biochemistry, Center of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, Brazil
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  • Bruno L. Batista,

    1. Department of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, SP, Brazil
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  • Denise Grotto,

    1. Department of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, SP, Brazil
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  • Fernando Barbosa Jr,

    1. Department of Pharmaceutical Sciences, University of São Paulo, Ribeirão Preto, SP, Brazil
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  • Solange C. Garcia,

    1. Laboratory of Toxicology, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
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  • Tatiana Emanuelli

    Corresponding author
    • Integrated Center for Laboratory Analysis Development (NIDAL), Department of Alimentary Technology and Science, Center of Rural Sciences, Federal University of Santa Maria, Santa Maria, Brazil
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T. Emanuelli, Integrated Center for Laboratory Analysis Development (NIDAL), Department of Alimentary Technology and Science, Center of Rural Sciences, Federal University of Santa Maria, Santa Maria, Brazil.

E-mail: tatiemanuelli@gmail.com

ABSTRACT

Oxidative stress has been shown to be involved in lead and cadmium toxicity. We recently showed that the activity of the antioxidant enzyme thioredoxin reductase (TrxR) is increased in the kidneys of lead-exposed rats. The present study evaluated the blood cadmium and blood lead levels (BLLs) and their relationship with hematological and oxidative stress parameters, including blood TrxR activity in 50 painters, 23 battery workers and 36 control subjects. Erythrocyte δ-aminolevulinate dehydratase (δ-ALA-D) activity and its reactivation index were measured as biomarkers of lead effects. BLLs increased in painters, but were even higher in the battery workers group. In turn, blood cadmium levels increased only in the painters group, whose levels were higher than the recommended limit. δ-ALA-D activity was inhibited only in battery workers, whereas the δ-ALA-D reactivation index increased in both exposed groups; both parameters were correlated to BLLs (r = −0.59 and 0.84, P < 0.05), whereas the reactivation index was also correlated to blood cadmium levels (r = 0.27, P < 0.05). The changes in oxidative stress and hematological parameters were distinctively associated with either BLLs or blood cadmium levels, except glutathione-S-transferase activity, which was correlated with both lead (r = 0.34) and cadmium (r = 0.47; P < 0.05). However, TrxR activity did not correlate with any of the metals evaluated. In conclusion, blood TrxR activity does not seem to be a good parameter to evaluate oxidative stress in lead- and cadmium-exposed populations. However, lead-associated changes in biochemical and hematological parameters at low BLLs underlie the necessity of re-evaluating the recommended health-based limits in occupational exposure to this metal. Copyright © 2011 John Wiley & Sons, Ltd.

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