Fig. 1.

VEGF preconditioning associated with increased vessel density is sufficient to promote a dose-dependent increase in DG neurogenesis. (A) VEGF was induced at the indicated time for a duration of 1 mo (red boxes). Depicted ages on the left represent the age at euthanasia. (B and C) Immunostaining for DCX reveals enhanced neurogenesis under both on and on>off experimental regimes. Note also that MVD is increased in both cases, as highlighted by CD31 staining (quantifications are shown in Fig. 3). (Scale bar, 100 μm.) (D) MVD and DCX⁺ cell density were determined for each mouse participating in this experiment (values presented represent averages calculated from six sections per animal) and plotted as DCX⁺ cell density versus MVD per each individual mouse. Note that neurogenic increase is proportional to MVD increase regardless of whether VEGF was continuously on (Left) or switched off (Right), respectively. P = 0.0093 for the on group, and P = 0.0004 for the on>off group.