Title: Chronic exposure to low-dose of X-rays induces DNA double-strand breaks in mammalian cells

Authors: Claudia A. Grillo; Alba M. Güerci

Addresses: INIFTA (Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas), CCT-CONICET La Plata, UNLP, CC 16, Sucursal 4 (1900) La Plata, Argentina. ' IGEVET (Instituto de Genética Veterinaria), CCT-CONICET La Plata, UNLP, Argentina; Cátedra de Radiobiología y Dosimetría, Facultad de Ciencias Exactas, UNLP, La Plata, Argentina

Abstract: The purpose of present study is to evaluate the induction of clastogenic effect after chronic exposure to low dose of ionising radiation in both CHO-K1 cells and in their DNA Double-Strand Breaks (DSBs)-repair deficient mutant xrs-5. Cells were cultured for 14 dilution cycles and grown to confluency. Radiation treatment was performed once per cycle with 10 mGy X-rays to carry out the structural chromosome aberration test. The results showed a significant increase in the frequency of achromatic lesions (p < 0.001) in CHO-K1 cells. In addition, xrs-5 cells showed an increase of chromatid and chromosome-type aberrations (p < 0.001). Sequential exposure produced a level of DNA damage that is amplified through successive cycles triggering the efficient repair of DSBs. The increased damage in xrs-5 cells provides evidence that the non-homologous end-joining repair of DNA DSBs is involved after low dose X-ray exposure.

Keywords: chronic exposure; radiation serial effect; low dose radiation; X-rays; DNA damage; structural chromosome aberration test; mammalian cells; repair-deficient mutant cells; low radiation; radiation exposure; DNA double-strand breaks; DSBs; clastogenic effect; ionising radiation; X-ray exposure.

DOI: 10.1504/IJLR.2011.046165

International Journal of Low Radiation, 2011 Vol.8 No.3, pp.198 - 213

Available online: 22 Mar 2012 *

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