title: Blood thioredoxin reductase activity, oxidative stress and hematological parameters in painters and battery workers: relationship with lead and cadmium levels in blood.
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.
authors: Graduate Program on Toxicological Biochemistry, Center of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, Brazil.
authors: Greicy M M
authors: GM
authors: Conterato
authors: Rachel P
authors: RP
authors: Bulcão
authors: Rocheli
authors: R
authors: Sobieski
authors: Angela M
authors: AM
authors: Moro
authors: Mariele F
authors: MF
authors: Charão
authors: Fernando A
authors: FA
authors: de Freitas
authors: Fernanda L
authors: FL
authors: de Almeida
authors: Ana P L
authors: AP
authors: Moreira
authors: Miguel
authors: M
authors: Roehrs
authors: Raquel
authors: R
authors: Tonello
authors: Bruno L
authors: BL
authors: Batista
authors: Denise
authors: D
authors: Grotto
authors: Fernando
authors: F
authors: Barbosa
authors: Solange C
authors: SC
authors: Garcia
authors: Tatiana
authors: T
authors: Emanuelli
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001336:Automobiles; D015415:Biomarkers / Q000097:blood; D002104:Cadmium / Q000097:blood* / Q000633:toxicity; D004912:Erythrocytes / Q000187:drug effects / Q000201:enzymology; D006801:Humans; D007221:Industry; D007854:Lead / Q000097:blood* / Q000633:toxicity; D008297:Male; D016273:Occupational Exposure / Q000032:analysis*; D018384:Oxidative Stress / Q000187:drug effects*; D010150:Paint; D000623:Porphobilinogen Synthase / Q000378:metabolism; D013880:Thioredoxin-Disulfide Reductase / Q000097:blood*; D013997:Time Factors; D017132:Workplace / Q000592:standards; D055815:Young Adult
chemical_list: D015415:Biomarkers; D002104:Cadmium; D007854:Lead; D013880:Thioredoxin-Disulfide Reductase; D000623:Porphobilinogen Synthase