Micronucleus-Centromere Assay to Measure Ionizing Radiation Damage of Low Dose Occupational Exposure

Abstract

Background: The purpose of the present study was to assess the cytogenetic effect of chronic low dose radiation exposure of nuclear power plant workers using the micronucleus centromere assay. This method allows the differentiation between centromere-positive micronuclei containing whole chromosome and centromere-negative micronuclei containing acentric fragment pointing to clastogenic action of ionizing radiation. Methods: The effect of low dose occupational exposure was estimated in 32 nuclear power plant workers using in situ hybridization (FISH) with the human pancentromeric DNA probe for peripheral blood lymphocytes. Group of 17 persons from administrative staff served as reference control group. Results: Data on the number of micronuclei, centromere-positive micronuclei and centromere-negative micronuclei per 1000 binucleated cells for the workers were significantly higher compared with the control group (p = 0.001, p=0.01 and p=0.002 respectively). No differences in the studied indicators between smokers and non-smokers are observed. No correlation was found between age and frequency of micronuclei, centromere-positive and centromere-negative micronuclei. Conclusions: The slight increase of the micronucleus frequency with the accumulated dose, observed in the group of workers, is mainly due to an enhanced number of centromere-negative micronuclei. Thus, the application of the MN-centromere assay is suitable as the frequency of MNCM−is more useful marker instead of the total number of MN. Keywords: occupational exposure; NPP workers; micronucleus-centromere assay