The genotoxic potential of hexachlorocyclohexane (HCH) isomers (α-, β-, and γ-) which are organochlorine pesticides was tested in peripheral blood lymphocyte cultures from two donors by using the cytokinesis-block micronucleus assay. Micronucleus (MN) frequency, binucleated cells with micronucleus (BNMN), and cytokinesis-blocked proliferation index (CBPI) were determined as genotoxic and cytotoxic endpoints. At the concentration ranges tested (12.5-100 μg.L -1), all HCH isomers induced dose-dependent cytotoxic effects, γ-HCH being the most toxic. This isomer was also able to induce significant increase in MN frequency and BNMN cells indicating a genotoxic potential at 50 and 100 μg.L -1. The genotoxic test of β-HCH showed a positive induction of MN and BNMN cells at the highest concentration of 100 μg.L -1 and a significant cytotoxicity at 50 μg.L -1. Under the experimental condition used, α-HCH was unable to induce any significant increase in MN frequency confirming that α-HCH is a non-genotoxic agent.
Keywords: HCH isomers; cytotoxicity; genotoxicity; human lymphocytes; micronucleus test.