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Genotoxic evaluation of the herbicide paraquat in cultured human lymphocytes
G Ribas1, J Surrallés, E Carbonell
1Department de Genètica i de Microbiologia, Facultat de Ciències, Unversitat Autònoma de Barcelona, Spain.
Abstract:
The widely used herbicide paraquat was evaluated for genotoxicity in peripheral blood human lymphocyte cultures. Sister-chromatid exchanges (SCE), chromosome aberrations (CA), and micronuclei (MN) were scored as genetic endpoints. Paraquat was administered either alone or in combination with an external source of metabolic activation. Our data indicate that paraquat induced slight but significant increases in the frequency of SCE. This genotoxic effect was not modified by cotreatments with S9 fraction from rat liver. However, paraquat did not increase the frequency of CA and MN, indicating that this bipyridylium compound is not effective in these assays, which would mean a general lack of effectiveness of the herbicide to induce clastogenic damage. In addition, cotreatments with the S9 fraction, did not modify the genotoxic ability detected in the SCE assay.
Insights
The herbicide paraquat slightly increased sister-chromatid exchanges (SCE) in human lymphocytes but did not induce chromosome aberrations (CA) or micronuclei (MN). Metabolic activation did not alter these genotoxic effects.
Area of Science:
- Environmental Toxicology
- Genetics
- Cell Biology
Background:
- Paraquat is a widely used herbicide with known toxicity.
- Assessing the genotoxicity of environmental contaminants is crucial for public health.
- Human lymphocyte cultures are a standard model for evaluating chemical genotoxicity.
Purpose of the Study:
- To evaluate the genotoxic potential of the herbicide paraquat in human peripheral blood lymphocytes.
- To investigate the effects of paraquat on specific genetic endpoints: sister-chromatid exchanges (SCE), chromosome aberrations (CA), and micronuclei (MN).
- To determine if metabolic activation influences paraquat's genotoxicity.
Main Methods:
- Human peripheral blood lymphocyte cultures were treated with paraquat.
- Assays for sister-chromatid exchanges (SCE), chromosome aberrations (CA), and micronuclei (MN) were performed.
- Paraquat was tested alone and in combination with rat liver S9 fraction for metabolic activation.
Main Results:
- Paraquat induced a slight but statistically significant increase in the frequency of sister-chromatid exchanges (SCE).
- No significant increase in chromosome aberrations (CA) or micronuclei (MN) was observed.
- Metabolic activation with S9 fraction did not alter the genotoxic effects of paraquat on SCE, CA, or MN.
Conclusions:
- Paraquat exhibits a limited genotoxic potential, specifically inducing SCE in human lymphocytes.
- The herbicide does not appear to be clastogenic, as evidenced by the lack of effect on CA and MN.
- Metabolic activation does not enhance or diminish the observed genotoxic effects of paraquat.