Fig. 5

Ki67 immunohistochemistry shows dividing cells (arrows, with high magnification in insert) in the subgranular zone of the dentate gyrus in the control (n = 5) (a), P3 + 15 M (with 5 Gy γ-ray irradiation at postnatal day 3, n = 4) (b), P10 + 15 M (with 5 Gy γ-ray irradiation at postnatal day 10, n = 3) (c), P21 + 15 M (with 5 Gy γ-ray irradiation at postnatal day 21, n = 3) (d) mouse respectively. DCX immunohistochemistry shows newly generated neurons (arrows, with high magnification in insert) in the subgranular zone of the dentate gyrus in the normal control (e), P3 + 15 M (f), P10 + 15 M (g), and P21 + 15 M (h) group of mice respectively. NeuN immunohistochemistry shows mature neurons in the granule cell layer of dentate gyrus in the normal control (i), P3 + 15 M (j), P10 + 15 M (k), and P21 + 15 M (l) group of mice respectively. In P3 + 15 M group, the ventral blade of the stratum granulosum is not fully developed (arrows in j) (Insert in i–l shows magnified NeuN positive cells from the dashline rectangle in each Fig). One-way ANOVA followed by the Tukey’s post hoc test were used for statistical analyses indicate significant reduction of Ki67 (m), DCX (n) and NeuN (o) immunopositive cells. *P < 0.05 compared to the control, **P < 0.01 compared to the control, ***P < 0.001 compared to the control, ****P < 0.0001 compared to the control. ns: P > 0.05 no statistical significant difference compared to the control