Abstract
Previously we reported that yeast and Chinese hamster V79 cells cultured under reduced levels of background environmental ionizing radiation show enhanced susceptibility to damage caused by acute doses of genotoxic agents. Reduction of environmental radiation dose rate was achieved by setting up an underground laboratory at Laboratori Nazionali del Gran Sasso, central Italy. We now report on the extension of our studies to a human cell line. Human lymphoblastoid TK6 cells were maintained under identical in vitro culture conditions for six continuous months, at different environmental ionizing radiation levels. Compared to “reference” environmental radiation conditions, we found that cells cultured in the underground laboratories were more sensitive to acute exposures to radiation, as measured both at the level of DNA damage and oxidative metabolism. Our results are compatible with the hypothesis that ultra-low dose rate ionizing radiation, i.e. environmental radiation, may act as a conditioning agent in the radiation-induced adaptive response.
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Acknowledgments
FA, MCC, and MP are grateful to Prof Antonino Zichichi and the “Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi” (Cosmic Silence project) for awarding their junior investigator fellowships. All the authors are grateful for the partial support given by the Cosmic Silence project. The authors are also grateful to Prof. V. Tombolini and to the technical staff at the San Salvatore Hospital, Coppito, L’Aquila, for allowing irradiations of biological samples at the 6 MV linear accelerator. Thanks are also due to Mr. Marco Sabatini for his technical assistance.
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Carbone, M.C., Pinto, M., Antonelli, F. et al. The Cosmic Silence experiment: on the putative adaptive role of environmental ionizing radiation. Radiat Environ Biophys 48, 189–196 (2009). https://doi.org/10.1007/s00411-008-0208-6
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DOI: https://doi.org/10.1007/s00411-008-0208-6