Mutagenesis Advance Access originally published online on February 20, 2007
Mutagenesis 2007 22(3):201-207; doi:10.1093/mutage/gem004
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Environmental lead exposure increases micronuclei in children
ska
yskaDepartment of Genetic Toxicology, Institute of Occupational Medicine and Environmental Health, Sosnowiec, Poland 1Department of Biomedical Sciences, University of Bradford, Bradford, UK 2Obstetrics/Gynaecology and Reproductive Sciences, University of California, San Francisco, CA, 2: 94720, USA 3Department of Occupational and Environmental Health, Institute of Public Health, University of Copenhagen, Panum, Denmark
The objective of this pilot study was to investigate the contribution of environmental exposures to lead in the development of cytogenetic damage detected as the frequency of micronuclei (MN) in children. The other aim was to apply the MN assay in combination with fluorescence in situ hybridization (FISH) using a pan-centromeric chromosome probe to elucidate the formation mechanism of induced MN. The examined population was composed of 9-year-old children (n = 92), living in the region where non-ferrous ores are extracted and processed. The non-exposed group consisted of 49 children of the same age from an unexposed recreational area. Exposure to lead was assessed by determination of lead concentrations in blood (PbB) by atomic absorption spectrophotometry, whereas the level of selenium (Se) in serum was detected by using graphite furnace atomic-absorption spectrometry. The frequency of MN was determined by the cytokinesis-block MN assay and fluorescence in situ hybridization performed using a specific pan-centromeric probe. Environmental exposure to lead resulted in significantly increased levels of PbB (5.29 ± 2.09 versus 3.45 ± 1.20 µg/dl in controls), although the average level was much below the value of the biological exposure limit = 10 µg/dl. A negative correlation between lead in blood and Se in serum concentrations (P = 0.006) was found for the pooled study population. The results showed a significant difference (P < 0.0001) in the level of MN between the exposed and control group (standard MN test: 2.96 ± 2.36 versus 1.16 ± 1.28; FISH technique: 3.57 ± 3.02 versus 1.43 ± 1.69, respectively). The frequencies of both centromere-positive (C+MN) and centromere-negative (C-MN) micronuclei were significantly increased in exposed children; however, the contribution of C+MN in the total number of MN in peripheral blood lymphocytes of exposed children was significantly higher than in the controls what may suggest a pro-aneugenic effect of the exposure to lead. The results of multiple regression analysis indicated that the exposure to lead was an important factor affecting the increase in MN frequency what was confirmed by significant correlation between the PbB and MN levels. In conclusion, our results suggest that the exposure to lead may be associated with an increased frequency of MN, especially of C+MN; however, the influence of other factors (e.g. vitamins and minerals in the diet) cannot be excluded.
* To whom correspondence should be addressed. Tel: +48 32 266 08 85; Fax: +48 32 266 11 24 (ext. 166); Email: l.kapka{at}imp.sosnowiec.pl
Received on March 22, 2006; revised on December 19, 2006; accepted on January 8, 2007.