Efficacy of HUMN criteria for scoring the micronucleus assay in human lymphocytes exposed to a low concentration of p,p'-DDT

V Garaj-Vrhovac,G Gajski,S Ravlić

doi:10.1590/s0100-879x2008005000027

V Garaj-Vrhovac, G Gajski + Show 1 more

Open Access

https://doi.org/10.1590/s0100-879x2008005000027

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Abstract

The cytokinesis-block micronucleus (CBMN) assay is one of the standard cytogenetic tools employed to assess chromosomal damage subsequent to exposure to genotoxic/cytotoxic agents, and is widely applicable to plant, animal and human cells. In the present study, the CBMN assay was used to assess the baseline damage in binuclear human peripheral blood lymphocytes exposed to 25 microg/L p,p'-DDT for 1, 2, 24, and 48 h by measuring the frequency of micronuclei, nucleoplasmic bridges and nuclear buds. These new scoring criteria facilitated the detection of different types of clastogenic and aneugenic effects induced by this type of pollutant. With these criteria, CBMN can also be used to measure nucleoplasmic bridges which are considered to be consequences of chromosome rearrangements and nuclear buds which are biomarkers of altered gene amplification and gene dosage. The total number of micronuclei observed in binuclear human peripheral blood lymphocytes of the exposed samples (ranging from 32 to 47) was significantly greater (P < 0.05) than that detected in the unexposed (0 time) control sample, where the total number of micronuclei was 7. The number of nucleoplasmic bridges and nuclear buds obtained after 24 and 48 h was also significantly (P < 0.05) greater in the samples treated with p,p'-DDT than in the unexposed control samples. Thus, our results confirmed the usefulness of the new criteria applicable for the CBMN assay employed in measuring the DNA damage and its role of a sensitive cytogenetic biomarker.

Highlights

Over the last decade, the wide applicability of the in vitro micronucleus test in peripheral blood lymphocytes and the simplicity of scoring have made it an attractive cytogenetic tool to assess occupational and environmental exposures to genotoxic agents
The cytokinesis-block micronucleus (CBMN) assay solved the problem of variations in micronucleus frequency caused by the alterations in the proportion of dividing cells that may occur when cells are exposed to genotoxic agents, by restricting the scoring of micronuclei to once-divided cells [1]
The present study reports the results obtained with the CBMN assay, measuring the frequency of micronuclei, nucleoplasmic bridges and nuclear buds in binuclear human lymphocytes exposed to a very low concentration of p,p’-DDT

Summary

Introduction

The wide applicability of the in vitro micronucleus test in peripheral blood lymphocytes and the simplicity of scoring have made it an attractive cytogenetic tool to assess occupational and environmental exposures to genotoxic agents. Except for cytogenetic damage measured by the number and distribution of micronuclei, according to the new criteria for micronuclei scoring, the CBMN assay detects the nucleoplasmic bridges, as well as nuclear buds.

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