Centro Universitário Feevale, Instituto de Ciências da Saúde, Novo Hamburgo, RS, Brazil.
Mutat Res. 2010 Mar 29;697(1-2):24-32. doi: 10.1016/j.mrgentox.2010.01.009. Epub 2010 Jan 25.
In human biomonitoring, factors such as age, gender, smoking habit and alcohol consumption are usually considered and identified as agents that exert an impact on genotoxicity biomarkers. However, as a rule, factors like micronutrient status are not considered in biomonitoring studies. This paper reports on genotoxic damage in Pb-exposed workers using data obtained from the cytokinesis-block micronucleus (CBMN) cytome assay and alkaline comet assay with silver staining, considering folate and vitamin B12 nutritional status. Analysis of the results showed that the Pb-exposed group presented a 24-fold higher Pb content in the blood compared to controls. The Pb-exposed workers presented significantly greater micronuclei (MNi) counts (Z=7.9583; p<0.0001) and DNA damage, assessed by the comet assay (DF: Z=7.7056; p<0.0001 and DI: Z=7.4749; p<0.0001), but no correlation with Pb blood concentrations were detected. These two groups did not differ significantly concerning folate and vitamin B12 levels. Regarding folate, it is possible that this similarity is associated with folic acid flour-enrichment, introduced in Brazil in 2004 to prevent neural tube defects. The mean folate level obtained in the Pb-exposed group was 6.18ng/ml. The subgroup of individuals with serum folate levels equal to or higher than the mean presented significantly higher MNi (Z=2.3776; p=0.017) and nucleoplasmic bridge (NPB) frequencies (Z=1.9850; p=0.047) in peripheral blood lymphocytes. A significant positive correlation was observed between the age of Pb-exposed workers and MNi frequencies (Gamma=0.3328; p<0.001), NPBs (Gamma=0.1832; p<0.042) and DNA damage assessed by the comet assay (DF: Gamma=0.1764; p=0.035 and DI: Gamma=0.11852; p=0.028). These findings suggest that high folate levels alone do not guarantee protection against genotoxic damage. Moreover, folic acid supplementation should be studied using more efficient approaches to determine safe amounts and potential deleterious effects.
在人体生物监测中，通常会考虑年龄、性别、吸烟习惯和饮酒等因素，并将其确定为对遗传毒性生物标志物产生影响的因素。然而，作为一项规则，生物监测研究通常不会考虑像微量营养素状态这样的因素。本文报告了使用胞质阻滞微核（CBMN）细胞测定和碱性彗星试验（用银染色）获得的数据，考虑到叶酸和维生素 B12 营养状况，在接触铅的工人中遗传毒性损伤的情况。分析结果表明，与对照组相比，接触铅的工人血液中的铅含量高出 24 倍。接触铅的工人微核（MNi）计数显著增加（Z=7.9583；p<0.0001），彗星试验评估的 DNA 损伤也显著增加（DF：Z=7.7056；p<0.0001 和 DI：Z=7.4749；p<0.0001），但未检测到与血铅浓度之间的相关性。这两组在叶酸和维生素 B12 水平方面没有显著差异。关于叶酸，这种相似性可能与 2004 年引入巴西的叶酸面粉强化有关，旨在预防神经管缺陷。接触铅组获得的平均叶酸水平为 6.18ng/ml。血清叶酸水平等于或高于平均值的个体，其外周血淋巴细胞中的 MNi（Z=2.3776；p=0.017）和核质桥（NPB）频率（Z=1.9850；p=0.047）显著升高。接触铅工人的年龄与 MNi 频率（Gamma=0.3328；p<0.001）、NPBs（Gamma=0.1832；p<0.042）和彗星试验评估的 DNA 损伤（DF：Gamma=0.1764；p=0.035 和 DI：Gamma=0.11852；p=0.028）之间存在显著正相关。这些发现表明，仅高叶酸水平并不能保证免受遗传毒性损伤。此外，应该使用更有效的方法来研究叶酸补充剂，以确定安全剂量和潜在的有害影响。
