Figure 3.

Panel (A–F). More Olig 2 expressing cells survive after NMDA exposure in the presence of TSC1. Examples of expression of the transcription factor Olig2 in the corpus callosum (CC) and SVZ 14 days after injection. Animals injected with saline displayed a large number of Olig2-positive cells in the CC (A) and a reduced number in the sub-ventricular zone (SVZ, D) suggesting that the vast majority of OLP had already migrated to the CC. (B) The CC of NMDA injected mice showed fewer cells and less intensely labeled cells while some intensely labeled cells were found in the SVZ (E). (C) the CC of the mouse injected with NMDA + TSC1 showed an extensive area containing Olig2-mRNA, this particular section shows the injection site (IS) devoid of Olig2-expressing cells but surrounded by intensely labeled OL progenitors. (F) Some Olig2-expressing cells were still present in the SVZ. (C) View of the injection site at the level of the CC of a mouse co-injected with NMDA and TSC1. The intensity of the label was low and the number of cells appeared reduced in both regions when compared to saline injected mice. (G) Quantitative data of Olig2-expressing cells. In animals injected with NMDA alone, the total number of Olig2-expressing cells in the CC and SVZ was reduced when compared to the total number of cells present in mice injected with saline. In contrast, there were more Olig2-expressing cells in the SVZ, than in animals injected with saline. Interestingly, with the N + TSC1 injection the total number of Olig2-positive cells in the CC and the SVZ was partially restored to 78% and almost to an equal distribution in the SVZ and the CC, suggesting that Olig2 positive cell migration was not disrupted by NMDA in the presence of TSC1. Values are expressed as mean ± SEM of the counts of 6 fields per area from three independent experiments. p ≤ 0.05. All differences across treatments were significant.