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Endocrine disrupting chemicals study

Researchers in the Endocrine Disruption Group at the Athlone Institute of Technology have been using the comet assay as a tool for measuring DNA damage caused by endocrine disrupting chemicals (EDCs). Screening EDCs for genotoxicity can provide valuable information in the evaluation of their possible carcinogenic potential. The first stage of carcinogenesis is normally rapid and irreversible and is believed to involve a change in the genetic material of the cell.

A diverse range of EDCs were examined, using an in vitro test system, for critical events required for the onset of carcinogenesis in vivo.

• 4-Octylphenol (alkylphenol),
• bisphenol A (plasticiser),
• coumestrol and genistein (phytoestrogens),
• 2,4-dichlorophenoxyacetic acid and toxaphene (pesticides),
• and ethinylestradiol (synthetic hormone)
were investigated for potential mutagencicity, DNA strand breakage, clastogenicity and DNA repair.

The comet assay was used to ascertain the genotoxic potency of the EDCs through induction of DNA strand breaks in human hepatoma cells (HepG2). The use of the HepG2 cell line in the comet assay demonstrates toxicity from a mammalian perspective. The comet assay was carried out and tail moment was chosen as a measure of DNA damage. The data was obtained using a computerised image analysis system – Comet Assay IV from Perceptive Instruments Ltd. Statistically significant induction in DNA damage was observed in the comet assay after treatment with 1 × 10−8 molar bisphenol A, toxaphene and coumestrol. During this investigation, the researchers established that a number of EDCs have the ability to induce mutagenesis, clastogenicity (in the form of DNA strand breaks), micronuclei formation and unscheduled DNA synthesis indicating DNA repair following damage.

Case study based upon:
Screening for Genotoxicity and Oestrogenicity of Endocrine Distrupting Chemicals in vitro. KM Quinn-Hosey, JJ Roche, AM Fogarty, CA Brougham Journal of Environmental Protection Vol. 3 No. 28, 2012, pp. 902-914.