Chronic Exposure to Low Dose of X-rays Induces DSBs in Mammalian Cells

GRILLO C.; GÜERCI A.

International Journal of Low Radiation

Institut national de la santé et de la recherche médicale

Año: 2010

1477-6545

The purpose of present study is to evaluate the induction of clastogenic effect after chronic exposure to low dose of ionizing radiation in both CHO-K1 cells and in their DSB-repair deficient mutant xrs-5. Cells were cultured for 14th dilution cycles and growth 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 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 cytogenetic damage in xrs-5 cells provides evidence that NHEJ repair of DNA double-strand breaks is involved after low dose X-ray exposure.th dilution cycles and growth 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 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 cytogenetic damage in xrs-5 cells provides evidence that NHEJ repair of DNA double-strand breaks is involved after low dose X-ray exposure.