Fig. 4.

Osteopontin (OPN) supports neurogenesis after stroke. Before photothrombosis (PT) (baseline) and at various time points after treatment, the total flux of photons was measured via bioluminescence imaging (BLI) as a surrogate for the number of doublecortin-positive (DCX⁺) neuroblasts. a Quantification of total flux was performed for each hemisphere and time point, as demonstrated on representative images, and a ratio was calculated between the hemispheres (the red rectangles in the baseline scan demonstrate measured ROIs of ipsi- and contralateral hemisphere). b Between day (D)7 and D28 after i.c.v. injection of OPN into stroke mice, the ratio between right (injected) and left (contralateral) hemisphere regarding the total flux of photons was significantly higher compared to phosphate-buffered saline (PBS)-injected stroke mice, consistent with increased expansion of DCX⁺ neuroblasts (means ± SEM; **p < 0.01). Note that 2 days after injection, total flux of photons was transiently enhanced in the contralateral hemisphere of OPN-treated mice (means ± SEM; *p < 0.05; **p < 0.01). c Representative immunohistochemical images of DCX⁺ cells (red) costained with Hoechst (blue) in the subventricular zone (SVZ) ipsilateral to the i.c.v. injection in mice subjected to photothrombotic stroke. The number of DCX⁺ cells was increased 28 days after OPN treatment (right panels) compared with control (left panels; scale bars = 200 μm). d In mice subjected to photothrombotic stroke, the area covered by DCX⁺ cells in the SVZ was significantly increased in OPN-treated mice compared with PBS-injected controls after 28 days. This was observed in both SVZ, ipsi- as well as contralateral to i.c.v. injection (means ± SEM; ***p < 0.001). e Representative immunohistochemical images reveal DCX⁺ neuroblasts (red) costained with Hoechst (blue) in the peri-infarct area in mice 14 days after OPN treatment (right panels) but not in control animals (left panels; scale bars = 100 μm)