Figure 2.

Increased number of newly generated neural progenitors and astrocytes induced by pluripotency factor expression in the subventricular zone. After the induction of cerebral ischemia, the doxycycline (DOX)-inducible reprogrammable mice were infused with two dose of doxycycline (12 ng/day, DOX-L; 1,200 ng/day, DOX-H) or phosphate buffered saline (PBS, control buffer) into the right lateral ventricle for 7 days. To identify newly generated cells, the mice were daily injected daily with 5-bromo-2-deoxyuridine (BrdU) for 12 days. Four weeks after ischemia induction, histologic evaluations were performed. (a) The density of BrdU⁺ cells in the subventricular zone was significantly higher in both the DOX-H and DOX-L groups than in the PBS controls. n = 5/group; *P < 0.05, **P < 0.01, and ***P < 0.001 (one-way analysis of variance (ANOVA) followed by a post-hoc Bonferroni comparison). (b–d) The density of newly generated neural progenitors, astrocytes, and neurons was determined through confocal microscopy by calculating the density of cells triple positive for 4ʹ,6-diamidino-2-phenylindole (DAPI) (blue, nuclei), BrdU (green), and cell type–specific markers such as Nestin, GFAP, and βIII-tubulin, respectively. The densities of BrdU⁺Nestin⁺ (b) and BrdU⁺GFAP⁺ cells (c) but not BrdU⁺βIII-tubulin⁺ cells (d) in both the DOX-H and DOX-L groups were significantly higher than in the PBS controls. n = 5/group; *P < 0.05, **P < 0.01, and ***P < 0.001 (one-way ANOVA followed by a post-hoc Bonferroni comparison). (e–m) Representative confocal microscopic images. (g,j) Cells triple positive for DAPI, BrdU, and cell type–specific markers are indicated with white arrow heads in the right panel. Scale bars = 25 μm. In panels a–d, bars, mean + SEM.