Persistence of genetic damage in mice exposed to low dose of X rays.
OBJECTIVE
The aim of this work was to evaluate the persistence of genetic damage in CBA/J mice treated with a single irradiation of 0.1 or 1 Gy of X rays.


METHODS
Peripheral blood was collected from irradiated and control mice after 30 min, 24 h, 7 days, 1, 3 and 6 months from exposure and analysed by comet assay. To investigate if the whole-body irradiation affect DNA repair, half of the sampled blood cells were in vitro-irradiated with additional 4 Gy and immediately analysed. Six months from exposure haematopoietic organs were sampled for measuring apoptotic index.


RESULTS
In mice exposed to 1 Gy genetic damage was initially high and decreased during the experimental-time, while in the 0.1 Gy group damage, at first low, persisted and slightly increased. The 0.1 Gy-irradiated mice showed also a time-dependent increasing sensitivity to the in vitro-irradiation. Six months after whole-body irradiation, the percentage of apoptotic cells observed in haematopoietic compartments from 0.1 Gy-irradiated mice was significantly higher compared to controls and to 1 Gy mice.


CONCLUSIONS
Results demonstrated that a single exposure to low-dose might induce long-term damage. Persistence of genetic damage might have relevant implications for estimating risk for low doses.
Giovanetti
Anna
A
ENEA ION-IRP (Ente per le Nuove Tecnologie, l'Energia e l'Ambiente-Istituto di Radioprotezione), Research Centre Casaccia, Rome, Italy. giovanetti@casaccia.enea.it
Deshpande
Trivikram
T
Basso
Emiliano
E
D000818:Animals; D017209:Apoptosis; D001773:Blood Cells / Q000473:pathology / Q000528:radiation effects; D001853:Bone Marrow / Q000473:pathology / Q000528:radiation effects; D020552:Comet Assay; D004249:DNA Damage; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D018384:Oxidative Stress / Q000528:radiation effects; D011833:Radiation Injuries, Experimental / Q000209:etiology / Q000473:pathology; D013154:Spleen / Q000473:pathology / Q000528:radiation effects; D014916:Whole-Body Irradiation / Q000009:adverse effects*