Figure 2.

Longitudinal and transversal decays of newborn cell populations. (A) Loss of BrdU⁺ cells per day, calculated as the total number of BrdU⁺ cells lost in the hippocampus during the periods 2d–4d, 4d–10d, and 10d–30d. N per group as in Fig. 1C. The effect of age in the loss of BrdU⁺ cells per period was analyzed using 1-way ANOVA: F(2,12) = 134.198, p < 0.001 at 1 m; F(2, 12) = 83.114, p < 0.001 at 2 m; F(2,9) = 553.774, p < 0.001 at 6 m; F(2, 21) = 94.635, p < 0.001. Holm-Sidak was used as a posthoc test.*, ** and *** indicate p < 0.05, p < 0.01 and p < 0.001 between periods for each age, respectively. (B) Cell loss rate of BrdU⁺ cells, calculated as the percentage of BrdU⁺ cells lost from the number of BrdU⁺ cells at 2d at each interval in the hippocampus. N per group as in Fig. 1C. The effect of the period in the loss of BrdU⁺ cells at each age was analyzed using 1-way ANOVA: F(3,17) = 2.593, p = 0.086 at 2d–4d; F(3,17) = 10.098, p < 0.001 at 4d–10d; F(3,20) = 2.66, p = 0.076 at 10–30d. Holm-Sidak was used as a posthoc test. a, b, and c represent significance respect to 1 m, 2 m, and 6 m, respectively. Two symbols are used for p < 0.01 and three for p < 0.001. Bars represent mean ± SEM. (C) Longitudinal decay of BrdU⁺ cells over the time course (2d–30d), calculated as an exponential curve with plateau. Fitting curve, cell half-life, survival plateau (%), and R² are indicated (further data is shown in Table S7). The longitudinal decay of 1 m mice in 1x BrdU, 4x BrdU, and 8x BrdU paradigms is shown in Fig. S2E. (D) Representative confocal z-stacks of the DG of 1 and 12 m mice at 30d after the BrdU injections. BrdU⁺ cells (magenta) were co-labeled with the mature neuronal marker NeuN (in cyan) or the astrocyte marker GFAP (in red). DAPI staining indicated cell nuclei (in white). Scale bars = 10 µm; z = 14 µm. (E) Expression of NeuN and GFAP in the BrdU⁺ cells at 30d (in %). N = 4 at 1 m and 2 m, N = 6 at 6 m, and N = 5 at 12 m for % NeuN⁺ cells. N = 9 at 1 m and 2 m, N = 10 at 6 m, and N = 20 at 12 m for % GFAP⁺ cells.1-way ANOVA analysis was F(3,15) = 10.913, p < 0.001 for % NeuN⁺ cells and F(3,44) = 4.18, p = 0.011 for % GFAP⁺ cells. Holm-Sidak was used as a posthoc test. a, b, and c represent significance respect to 1 m, 2 m, and 6 m, respectively. Two symbols are used to represent p < 0.01 and three for p < 0.001. Bars represent mean ± SEM. Raw data is shown in Tables S2 and S3. (F) Absolute number of newborn neurons (BrdU⁺, NeuN⁺) and astrocytes (BrdU⁺, GFAP⁺) at 30d in the hippocampus. N = 5 at 1 m and 2 m, N = 4 at 6 m, and N = 15 at 12 m for % NeuN⁺ BrdU⁺ cells; N = 5 at 1 m and 2 m, N = 4 at 6 m, and N = 15 at 12 m for GFAP⁺, BrdU⁺ cells.1-way ANOVA analysis was F (3,25) = 115.154, p < 0.001 for NeuN⁺, BrdU⁺ cells and F(3,25) = 53.589, p < 0.001 or GFAP⁺, BrdU⁺ cells. a, b, and c represent significance respect to 1 m, 2 m, and 6 m, respectively. Two symbols are used to represent p < 0.01 and three for p < 0.001. Bars represent mean ± SEM. (G) Transversal decay of BrdU⁺ (2 h), BrdU⁺ NeuN⁺ (30d) and BrdU⁺ GFAP⁺ (30d), is best fitted with an exponential curve. Fitting curve, cell half-life, and R² are indicated (further data is shown in Table S7). The transversal decay of human neuroblasts labeled with doublecortin is shown in Fig. S2F,G. N per group as in Fig. 2F.