Comet assay in human biomonitoring studies: reliability, validation, and applications

Area of Science:

• Biomonitoring
• Genotoxicology
• Oxidative Stress

Background:

• The comet assay (single-cell gel electrophoresis) is a sensitive method for detecting DNA strand breaks in individual cells.
• Human lymphocytes are suitable for biomonitoring due to the assay's ease of application.
• Oxidative DNA damage can be assessed by modifying the comet assay with lesion-specific endonucleases.

Purpose of the Study:

• To evaluate the reliability and reproducibility of the modified comet assay for detecting oxidative DNA damage in human lymphocytes.
• To assess the natural intra- and interindividual variability of lymphocyte DNA damage in healthy volunteers.
• To investigate the application of the assay in human disease and occupational exposure studies.

Main Methods:

• Single-cell gel electrophoresis (comet assay) adapted for human lymphocytes.
• Inclusion of a DNA incubation step with lesion-specific endonucleases to detect DNA base oxidation.
• Comparison of duplicate gel results and assessment of variability in healthy human volunteers.

Main Results:

• The modified comet assay demonstrated reliability and reproducibility for measuring DNA strand breaks and base oxidation.
• Natural intra- and interindividual variability in lymphocyte DNA damage was quantified in healthy subjects.
• The assay was successfully applied to study DNA damage in human disease and occupational exposure contexts.

Conclusions:

• The modified comet assay is a reliable and reproducible method for assessing oxidative DNA damage in human lymphocytes.
• The assay is suitable for human biomonitoring, providing insights into DNA damage related to disease and environmental exposures.
• Understanding natural variability is crucial for interpreting biomonitoring data from occupational and disease studies.