Fig 3. SHH silencing reduces grafted NPC-mediated endogenous neurogenesis.

Effects of SHH and GDNF silencing on grafted NPC-induced endogenous neurogenesis and neuroblast migration were examined. As shown in A-E, in comparison to animals with control NPC implants, those transplanted with SHH and GDNF+SHH silenced NPCs showed reduced brdU labeling within the host forebrain SVZ niche. In support of these data, cell counts indicated lower numbers of brdU⁺ cells in the ipsilateral SVZ of rats that had received SHH or GDNF+SHH silenced NPC transplants (arrows, examples of DAB labeled cells counted in K, L, stereological counts in M). Further, migrating brdU⁺/dcx⁺ neuroblasts, which were observed in the striatal parenchyma, particularly in regions neighboring grafts, in control NPC receiving animals (arrows, G), were missing in those with SHH or GDNF+SHH silenced cells (I, J). With regard to animals harboring GDNF silenced cells, a significant reduction in brdU⁺ cells (M) or an absence of brdU⁺/dcx⁺ cells in the lesioned and grafted striatum (H) was not observed. Values are expressed as mean ± SEM [***p<0.001 compared to shC, one way ANOVA with Bonferroni’s post-hoc test]. Scale bars: A-E—50 μm, F-J—10 μm, K, L—50 μm.