ORIGINAL PAPER Use of the DBD–FISH technique for detecting DNA breakage in response to high doses of X-rays Elva I. Corte ´s-Gutie ´rrez • Martha I. Da ´vila-Rodrı ´guez • Ricardo M. Cerda-Flores • Jose ´ Luis Ferna ´ndez • Carmen Lo ´pez-Ferna ´ndez • Jaime Gosa ´lvez Received: 18 February 2014 / Accepted: 13 June 2014 / Published online: 24 June 2014 Ó Springer-Verlag Berlin Heidelberg 2014 Abstract The aim of this study was to generate a dose– response curve using the DNA breakage detection–fluo- rescent in situ hybridization (DBD–FISH) test as a bio- marker of initial genetic effects induced by high doses of X-rays. A dose–response curve was obtained by measuring the ex vivo responses to increasing doses (0–50 Gy) of X-rays in the peripheral blood lymphocytes of ten healthy donors. The overall dose–response curve was constructed using integrated density (ID; area 9 fluorescence intensity) as a measure of genetic damage induced by irradiation. The correlation coefficient was high (r = 0.934, b 0 = 10.408, and b 1 = 0.094). One-way ANOVA with the Student– Newman–Keuls test for multiple comparisons showed significant differences among the average ln ID values according to dose. Our results suggest the usefulness of the DBD–FISH technique for measuring intrinsic individual cellular radio sensitivity ex vivo. Keywords DBD–FISH Á X-rays Á Radiosensitivity Á DNA damage Introduction Individual radiosensitivity is a personal characteristic that is associated with an increased reaction to ionizing radia- tion (Twardella and Chang-Claude 2002). The exposure of humans to effective doses of ionizing radiation presumes a heterogeneous response that has an impact on both its acute and delayed effects, as cancer. Ionizing radiation produced both single-strand DNA breaks (SSB) and double-strand DNA breaks (DSB), with the latter being induced 25–40 times less than the former (Piette 1991; Sies and Menck 1992; Olive 1998; Hall and Giaccia 2006; Cadet et al. 2009; Ljungman, 2009). It is estimated that 1 Gy of X- or gamma rays initially produces around 1000 SSB and 20–40 DSB (Ward 1988). Single-strand DNA breaks are the principal lesion among the various DNA lesions. If DSB remain unrepaired or are misrepaired, gene mutations, chromosomal aberra- tions, or cell death can occur (Frankenberg et al. 1981; Bryant 1984; Obe et al. 1992). The construction of in vitro dose–response curves using different radiation doses can be used to identify individuals who depart significantly from the standard pattern, indi- cating the presence of either radiosensitivity or radiore- sistance (Lloyd 1998; Schroder and Heimers 2002; Natarajan and Kesavan 2005; Gu ¨erci et al. 2011). Several methods for assessing radiation-induced genetic damage have been described by the International Atomic Energy Agency (IAEA 2011); examples include analysis of micronuclei (Streffer et al. 1998; An and Kim 2002; Neri et al. 2003), chromosome aberrations (Kanda 2000; E. I. Corte ´s-Gutie ´rrez (&) Á M. I. Da ´vila-Rodrı ´guez Department of Genetics, Centro de Investigacio ´n Biome ´dica del Noreste, Instituto Mexicano del Seguro Social, IMSS, C.P. 64720 Monterrey, NL, Mexico e-mail: elvacortes@cibinmty.net R. M. Cerda-Flores Nursing Faculty, Universidad Auto ´noma de Nuevo Leo ´n, Monterrey, Mexico J. L. Ferna ´ndez Genetics Unit, INIBIC- Complejo Hospitalario Universitario A Corun ˜a, A Corun ˜a, Spain C. Lo ´pez-Ferna ´ndez Á J. Gosa ´lvez Unit of Genetics, Department of Biology, Universidad Auto ´noma de Madrid, 20849 Madrid, Spain 123 Radiat Environ Biophys (2014) 53:713–718 DOI 10.1007/s00411-014-0555-4