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内容記述 |
Radiation-induced clustered DNA damage is closely linked to the biological effects of radiation. In this study, atomic force microscopy was used to evaluate the complexity of clustered DNA damage in genomic DNA from TK6 cells exposed to low-dose ionizing radiation. By isolating and concentrating damaged DNA molecules, we estimated the extent of damage clustering in vivo. Our results showed that X-rays and Fe-ion beams induced clustered DNA damage, whereas Fentons reagent did not, reinforcing its significance as a unique signature of ionizing radiation. Notably, Fe-ion beams generated more complex clustered damage, often consisting of more than two lesions, which was rare in X-ray exposure. Repair analysis revealed that non-DSB clustered damage was efficiently repaired in TK6 cells after both X-ray and Fe-ion irradiation. However, complex DSBs, which were frequently induced by Fe-ion beams, exhibited poor repair efficiency. These findings emphasize the distinct nature and repair challenges of clustered DNA damage caused by high- LET radiation. |
