Cytotoxicity and genotoxicity of clothianidin in human lymphocytes with or without metabolic activation system

Area of Science:

• Toxicology
• Genetics
• Environmental Science

Background:

• Clothianidin (CHN) is a widely used neonicotinoid insecticide.
• Limited research exists on the cytotoxic and genotoxic impacts of CHN and its metabolites in human cells.
• Understanding these effects is crucial for assessing environmental and human health risks.

Purpose of the Study:

• To investigate the cytotoxic and genotoxic potential of CHN and its metabolites.
• To evaluate these effects in human lymphocyte cultures with and without a metabolic activation system (S9 mix).
• To utilize chromosomal aberration (CA) and micronucleus (MN) tests for comprehensive assessment.

Main Methods:

• Human peripheral blood lymphocytes were cultured and treated with varying concentrations of CHN (25, 50, 100 µg/ml).
• Treatments were conducted in the presence (3h) and absence (48h) of the S9 mix.
• Cytotoxicity and genotoxicity were assessed using mitotic index (MI), nuclear division index (NDI), chromosomal aberration (CA), and micronucleus (MN) assays.

Main Results:

• CHN induced significant cytotoxic and genotoxic effects in the absence of S9 mix, evidenced by decreased MI and NDI, and increased CA and MN formation.
• In the presence of S9 mix, CHN did not significantly induce cytotoxicity or genotoxicity.
• These findings suggest that CHN's direct action, rather than its metabolites, is responsible for the observed genotoxic effects under these experimental conditions.

Conclusions:

• Clothianidin demonstrates cytotoxic, cytostatic, and genotoxic potential in human lymphocytes, particularly without metabolic activation.
• Metabolites of CHN did not exhibit significant genotoxicity under the tested experimental conditions.
• The study highlights the importance of metabolic activation in evaluating the toxicological profile of insecticides like CHN.