Early response of neural stem/progenitor cells after X-ray irradiation in vitro.

We investigated the effect of oxidative stress on cell cycle regulation of neural stem/progenitor cells in neurosphere culture. We exposed murine neural stem/progenitor cells to 2 Gy of X-ray irradiation at 48 h after first passage. We found that G2 and G1-arrested cells increased at 3 and 12 h after X-ray irradiation, respectively by using laser scanning cytometer. We revealed that such G2 and G1 arrests were correlated with phosphorylation of cdc2 and p53, respectively by Western blotting analysis. Furthermore, we found that the effects of X-ray irradiation of neural stem/progenitor cells involved inactivation of Notch signal. These results suggest that the drastic response of neural stem/progenitor cells after X-ray irradiation occurred even in the short period.