Evaluation of Genotoxic effects of Chromium on tannery workers by various Cytogenetic assays

Abstract

Chromosomal aberration is an important biomarker for carcinogenesis. The study of DNA damage at the chromosomal level is an essential part of genetic toxicology. Different Chromium compounds are used in tanneries. Hexavalent chromium, Cr (VI) is considered as a human lung carcinogen with potentially widespread exposure. This study was designed specifically to evaluate cytogenotoxicity of chromium compounds used in leather industries on human peripheral blood lymphocytes by using a series of cytogenotoxic assays such as micronucleus test, chromosome aberration test and alkaline Comet assay. These tests are proved to be extremely useful techniques in cytogenotoxicity measurements. The micronucleus test assesses chromosomal damage by the formation of micronucleus on once-divided binucleatetd cells, whereas various types of structural chromosome aberrations and extent of DNA damage are detected by chromosome aberration and comet assay respectively. Different types of structural damages like Break, Gap and dicentric chromosomes were detected by Chromosome aberration test. Micronucleus test also revealed significant chromosomal damage in chromium exposed human blood cells. In line with results of Micronucleus test and Chromosome aberration test, significant DNA damage was also detected by Comet assay. The results of Comet assay indicate that chromium compounds induced significant increase in the comet tail DNA (%), tail moment and Olive tail moment; the parameters used to determine genotoxicity. These results from all three tests provide evidence that exposure to chromium and chromium compounds in human peripheral lymphocytes results in induction of DNA damage. Therefore the present study gives an indication of an association between chromium induced DNA damage and chromosomal instability.