Construction and Validation of a Dose-Response Curve Using the Comet Assay to Determine Human Radiosensitivity to Ionizing Radiation

Abstract

Individual radiosensitivity is an individual characteristic associated with an increased reaction to ionizing radiation. The purpose of our work is to establish a dose-response curve useful to classify individuals as radiosensitive or radioresistant. Thus, a dose-response curve was constructed by measuring in vitro responses to increasing doses (0 to 8 Gy) of gamma radiation in the comet assay. The obtained curve fit well with a linear equation in the range of 0 to 8 Gy. The overall dose-response curve was constructed for percent DNA in tail, as a measure of the genetic damage induced by irradiation. To probe the goodness of the constructed curve, a validation study was carried out with whole blood from two donors in a blind study. Results show that, for the two applied doses (2 and 6 Gy), the obtained values fit well inside the interval of confidence of the curve. In conclusion, our results demonstrate the usefulness of the comet assay in determining individual responses to defined doses of gamma radiation. The standard dose-response curve constructed may be used to detect individuals departing from reference values.

Acknowledgments

This study was partially funded by the Agencia Española de Cooperación Internacional. (A/018554/08) and the Generalitat de Catalunya (CIRIT; 2009SGR-725). L. A. Zúñiga was supported by a predoctoral fellowship from the Universitat Autònoma de Barcelona (PIF).