Fig. 2.

Lithium restored irradiation-induced alterations in dendrite arborization of doublecortin (DCX⁺) cells in the subgranular zone (SGZ) of the DG at PND 91. a DCX immunoreactivity in the GCL of the different treatment groups at PND 91. Scale bar = 100 µm. ×20 magnification. b Interleaved bar graph of the quantification of DCX⁺ cells in the GCL showing the effect of lithium treatment in the Sham group (**p = 0.0030) and in the Irr group (**p = 0.0023). Two-way ANOVA shows the effect of both treatments: irradiation (F_1,18 = 400.6, ^####p < 0.0001), lithium (F_1,18 = 28.70, ****p < 0.0001). c The phenotype of the radial (upper panel) and parallel (lower panel) processes in immature neurons at PND 91 was determined by double labeling for BrdU and DCX as shown in the representative confocal images of DCX+ (red), BrdU⁺ (green) and merged BrdU⁺–DCX⁺ cells in the GCL. Scale bar = 20 µm. d Pie chart of the percentages of BrdU cells double labeled for DCX and with either radial or parallel process phenotype. The percentages of radial processes were not affected by lithium treatment: in the Sham group p = 0.2341 and in the Irr group p = 0.5313. Two-way ANOVA shows the effect of irradiation on radial processes: irradiation (F_1,18 = 24.4, ***p = 0.0001), lithium (F_1,18 = 3.96, p = 0.0619). The percentages of parallel processes were increased after irradiation, and lithium treatment restored the percentages of parallel processes in the Irr group (****p < 0.0001) but did not affect the Sham group (p = 0.0570). Two-way ANOVA: irradiation (F_1,18 = 33.59, ****p < 0.0001), lithium (F_1,18 = 34.75, ****p < 0.0001). The percentages of BrdU not labeled for DCX were not affected by irradiation but were increased in the IrrLi group (**p = 0.0094). Two-way ANOVA: interaction (F_1,18 = 5.277, *p = 0.0338). e Representative images of the dendritic tracing in DCX⁺ cells in animals for all experimental groups. f Dot plot graph of the cell body area showing no effect of either lithium or irradiation at PND 91. g Dot plot graph of the dendritic complexity of DCX⁺ immature neurons showing significant decrease in the Irr group compared with all the other groups at PND 91. Circle, triangle and square marks represent the value for each neuron in each animal. N (number of animals) = 3 in each group. Number of traced neurons is 15–20 in each animal. Linear mixed model, *p < 0.05, **p < 0.01, ***p < 0.001. Error bars represent point estimate and 95% confidence interval. h Scholl analysis of DCX⁺ immature neurons showing that lithium treatment restores the number of intersections in the distal part (50–60 µm) of the dendrites at PND 91 in the Irr but not in the Sham-treated group. N (number of animals) = 3 in each group. Number of traced neurons is 15–20 in each animal. Two-way ANOVA and post hoc Bonferroni test. *p < 0.05, ***p < 0.001 compared with the Irr group. Error bars represent SEM. ****p < 0.0001; **p < 0.01; *p < 0.05