Performance of the comet assay in a high-throughput version

Area of Science:

• Genotoxicity testing
• Molecular toxicology
• High-throughput screening

Background:

• The standard comet assay is time-consuming and limits sample throughput.
• There is a need for faster, more efficient methods for genotoxicity assessment.
• Previous guidelines for the comet assay were established by Tice et al. (2000).

Purpose of the Study:

• To introduce and validate a high-throughput comet assay (HTCA).
• To compare the HTCA with the standard comet assay using various genotoxic agents.
• To assess the efficiency and reliability of the HTCA for large-scale testing.

Main Methods:

• Development of a 96-well multichamber plate (MCP) for parallel processing.
• Cells were exposed to genotoxic agents (MMS, ethylnitrosourea, 4-nitroquinoline-1-oxide, cisplatin, H2O2).
• Samples in the MCP underwent simultaneous lysis, alkaline unwinding, electrophoresis, neutralization, and staining.
• An integrated viability assay (FDA assay) was performed post-treatment.

Main Results:

• The HTCA processes up to 400 samples per day, significantly increasing throughput.
• Similar genotoxicity results were observed between the HTCA and standard assay for MMS and H2O2.
• The integrated viability assay did not affect comet formation outcomes.
• Standard deviation for replicates was 3-20% at medium and high concentrations.

Conclusions:

• The HTCA is a validated, efficient method for genotoxicity determination.
• It offers substantial cost and time savings for testing industrial chemicals, environmental samples, and drug candidates.
• The HTCA is suitable for applications requiring the measurement of large numbers of samples.