Figure 3.

Exposure to high doses of ¹³⁷Cs γ rays perturbs progression through the cell cycle of NSPs derived from the SVZ. A single cell suspension of neural stem cell and progenitors was exposed to γ rays at 0, 0.5, and 8 Gy. Cells were fixed, stained with PI, and cell cycle analysis was performed at various times after irradiation. (a) Representative histograms from four individual experiments illustrate the distribution of cells in the phases of the cell cycle based on DNA content. (b) Quantitation of cell cycle analyses. After 24 and 48 hr of high-dose irradiation, a significant proportion of the cells were arrested in G2/M. Statistical analysis showed that 8 Gy of gamma rays also inhibited cell cycle progression at S phase after 24 hr (n = 4) and 48 hr (n = 3). **p < .01 by ANOVA followed by Dunnett’s multiple comparisons test compared with 0 Gy. Error bars indicate SEM. Data represent averages of the four independent experiments. SVZ = subventricular zone; NSPs = neural stem/progenitor cells; PI = propidium iodide; ANOVA = analysis of variance.