Fig. 1
![Fig. 1](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs11658-018-0092-2/MediaObjects/11658_2018_92_Fig1_HTML.png)
Results of the single cell gel electrophoresis (SCGE). a – Representative images of C6 cells after SCGE. The “comet tail” became longer as the dose of X-ray irradiation increased, indicating that DNA damage induced by X-ray irradiation at 1, 5, 10 and 15 Gy was more severe than that at 0 Gy (p < 0.05). b – The tail moments of U251 cells were larger than those of C6 cells when the cells were exposed to 0, 1, 5, 10 and 15 Gy X-ray irradiation. **p < 0.01