engleski

Assessment of Oxidative DNA Damage by Glyphosate Applying hOGG1 Modified Comet and Micronucleus Assay

Genetically modified crops resistant to glyphosate are being used more widely each year. The modification enables them to tolerate higher concentrations of the active ingredient. Thus, higher amounts of glyphosate are introduced into the environment. In our study we tested concentrations that are likely to be encountered in residential and occupational exposure (0.5, 2.91, 3.5 and 580 &micro ; g/ml). Evaluation was performed on human peripheral blood lymphocytes form three healthy, young volunteers. Technical glyphosate (98%) was tested with and without metabolic activation system (S9). Lymphocytes were treated for 4h at 37°C. Alkaline comet assay was modified by applying hOGG1 enzyme to detect 8-hydroxy-2'-deoxyguanosine as a result of oxidative DNA damage. Simultaneously, treated lymphocytes were used to set up cultures for micronucleus assay (MN). Micronuclei slides were hybridized with All Human Centromere Satellite Probes. The hOGG1 comet assay without S9 showed significant increase of the tail intensity only at 3.5 &micro ; g/ml, but not at highest concentration tested (580 &micro ; g/ml). The presence of S9 significantly elevated the tail length only at the 580 &micro ; g/ml. Altogether, the DNA damage detected was not dose dependent. Significant number of MN was observed only at the highest concentration when applying S9. Also, only for that treatment proportion of MN with centromere signal was significantly elevated indicating aneugenic effect. Our results suggest that only with S9, glyphosate may induce oxidative damage in human lymphocytes with threshold dose rather than dose dependent effect. Without a clear dose dependent effect further testing applying new cytogenetic methods is needed.

glyphosate; hOGG1 comet assay; micronucleus assay

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