Nuclear Science and Techniques

Abstract:

The two-tailed comet assay (2T-comet assay) is a method for simultaneously evaluating DNA single-strand breaks (SSBs) and double-strand breaks (DSBs). In the present study, the endonuclease DNase I and hydrogen peroxide were used to induce DSBs and SSBs in bone marrow mononuclear cells (BMMNCs) from mice, and the damaged DNAs were assessed with a 2T-comet assay. The results demonstrated that this method can detect and discriminate between BMMNC DNA SSBs and DSBs simultaneously. Using this method, we studied DNA damage in BMMNCs from female BALB/c mice after total body irradiation with X-rays and carbon ions. The results indicated that these two types of radiation induced serious DNA damage in BMMNCs in a dose-dependent manner. The DNA damage induced by carbon ions was more severe than that induced by X-rays at the same dose, and a high dose of carbon ion radiation was more likely to cause death in mice. The DSBs and SSBs induced by X-rays were the highest on the 3rd day post-IR. For carbon ion radiation, DSBs were the most serious on the 3rd day, while SSBs were more obvious on the 3rd day and 13th day post-IR. The ratio of DSBs/SSBs was clearly related to the different types of radiation.

Key words: Two-tailed comet assay, carbon ion irradiation, X-ray irradiation, Bone marrow mononuclear cells, DNA damage