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.

Assessment of Hematotoxicity and Genotoxicity among paint Workers in Assiut Governorate: a case control study

“…In agreement with our results the study of Moro et al (2010) and Conterato et al (2013) reported an increased MDA level in painters occupationally exposed to paint thinners.…”

“…MDA is formed as its end product. Anti-oxidant enzymes are defense system against oxidative stress (Barrera 2012; Conterato et al 2013).…”

Lead Exposure and Oxidative Stress: A Systematic Review

“…Eight studies reported significantly higher levels of GPx activity in the lead-exposed groups than in the controls (Monteiro et al 1985 ;Solliway et al 1996 ;Oktem et al 2004 ;Kasperczyk et al 2004aKasperczyk et al , 2012Han et al 2005 ;Ergurhan-Ilhan et al 2008 ;Conterato et al 2013 ). Five studies reported lower GPx activity in the lead-exposed groups than in the control groups (Sugawara et al 1991 ;Chiba et al 1996 ;Wasowicz et al 2001 ;Kasperczyk et al 2009 ;Grover et al 2010 ), and two studies reported no signifi cant differences between GPx activity and BLL (Garçon et al 2007 ;Rendon-Ramirez et al 2014 ).…”

“…Among these, 15 studies reported a signifi cant positive correlation between BLLs and MDA concentrations ( r = 0.15-0.80; p < 0.05). Only one study did not fi nd signifi cant association between BLLs and MDA concentration ( Conterato et al 2013 ). Four studies reported that TBARS were detected measuring LPO in body fl uids.…”

“…Among these, 6 studies observed that SOD and CAT activities were signifi cantly lower in groups exposed to lead (Sugawara et al 1991 ;Patil et al 2006a , b ;Mohammad et al 2008 ;Grover et al 2010 ;Conterato et al 2013 ). Four studies found that SOD activity was higher in exposed groups (Kasperczyk et al 2004b(Kasperczyk et al , 2012Malekirad et al 2010 ;Conterato et al 2013 ), and 1 of these studies reported that the increase was greater in the low lead-exposed subgroup (BBL, 35.0 ± 9.3 μg/dL) than in the high leadexposed subgroup (BBL, 44.2 ± 8.1 μg/dL) (Kasperczyk et al 2004b ). No significant difference was noted in CAT activity in these studies (Kasperczyk et al 2004b(Kasperczyk et al , 2012Malekirad et al 2010 ).…”