Application of cytogenetic endpoints and Comet assay on human lymphocytes treated with vincristine in vitro

The genotoxic potential of vincristine is assessed on human peripheral bloo d lymphocytes following administration of the drug at a dose 0.0875 mu g/ml by use of single cell gel electrophoresis - Comet assay (SCGE), analysis o f structural chromosome aberrations ICA), micronucleus assay (MN) and siste r chromatid exchange (SCE) analysis. In vitro treatment of human lymphocyte s with vincristine was performed on cells in G(o) phase, as well on lymphoc yte cultures 24 hours after stimulation with mitogen phytohemagglutinine. F or the Comet assay at 24, 48 and 72 h the treated cells were embedded in ag arose on slides, lysed with alkaline lysis solution and exposed to an elect ric field. DNA migrated within the agarose and Formed comets whose length d epends on the amount of DNA damage. For the analysis of structural CA cells were grown on F-10 medium for 48 hours, and for MN and SCE analysis for 72 hours. The results on SCGE showed an increase in tail length compared to c ontrol both in cells treated in G(o) and in cells treated 24 h after mitoge n stimulation. The amount of DNA damage was higher in cells treated with vi ncristine 24 h after mitogen stimulation. Administered concentration of dru g caused total inhibition of lymphocytes growth in 72-h cultures for MN and SCE analysis indicating strong microtubule distruptive effects of vincrist ine. Analysis of structural CA reveals chromatid breaks and acentric fragme nts as the main aberration types both in cells treated in G(o) and in cells treated 24 h after mitogen stimulation, Number of these aberrations was hi gher in cells treated in G(o) phase. Results obtained ill this study by use of different cytogenetic endpoints confirmed that vincristine exhibits bot h aneugenic and clastogenic effects on human lymphocytes.