Fig. 4.

Neurogenic enhancement in old mice is not accompanied by accelerated NSC depletion and is partly attributed to a reduction of age-related NSC quiescence. (A) Schematic representation of the VEGF on>off switching regime (red bar representing on episodes) and IdU labeling (100 mg/kg, three injections 1–2 d before euthanasia) in triple-transgenic mice also harboring a nestin-GFP reporter transgene. (B) Representative z-stack image of dividing RGLs. The x–y and y–z axes also show colocalization of GFP and IdU staining. (Scale bars, 20 μm.) (C and D) Quantification of RGLs per GCL volume unit and of IdU⁺ RGLs representing actively proliferating RGLs. (E) To adjust for changes in total RGL numbers, data were also plotted as the fraction of actively dividing RGLs in control and manipulated mice of the respective ages. (F) Regime of VEGF on/off switching and BrdU administration (1–2 d before euthanasia) to detect actively proliferating RGLs 4 mo after VEGF induction. (G) Quantification of RGLs per GCL volume unit and of the percentage of dividing RGLs when mice reached 6 mo of age. NS, not significant.