Fig. 2

Brain irradiation induced delayed, dose-dependent infiltration of bone marrow-derived cells. Chimera mice with bone marrow-expressing eGFP received brain irradiation (0 or 35 Gy) and were sacrificed at multiple time points. Sections from irradiated mice at a 1 day and b 6 months post-irradiation were stained with Hoechst solution, and photomicrographs were taken of the internal capsule. Scale bars: 100 μm. c Images illustrating the distribution of eGFP+ cells at 6 months were constructed for 0 and 35 Gy animals. Each dot represents one eGFP-expressing cell. d eGFP+ cells per square millimeter were quantified in three brain regions (the fimbria/fornix, corpus callosum/extreme capsule, and the hippocampus), beginning with the first section caudal to bregma containing fimbria or fornix. Data were analyzed by two-way ANOVA and Bonferroni post hoc tests comparing irradiated animals to controls for each time point, n = 4–5 mice per condition: **p ≤ 0.01 and ***p ≤ 0.001. e Chimera animals were irradiated with 0, 15, 25, 35, or 45 Gy to brain, sacrificed at 6 months post-irradiation and analyzed for eGFP+ cells per square millimeter. Data were analyzed by one-way ANOVA and Bonferroni post hoc tests comparing all of the doses, n = 4–5 mice per condition. Symbols used to distinguish statistical significances between doses: *0 Gy, + 15 Gy, and ^#25 Gy. One symbol represents p ≤ 0.05, two symbols represent p ≤ 0.01, and three symbols represent p ≤ 0.001