Figure 5.

Migrating neuroblasts formed elongated aggregates associated with blood vessels in the ischemic striatum. A–C, Double immunohistochemistry of the striatum with anti-PECAM-1 antibody (red) and anti-Dcx antibody (green) 18 d after ischemia induction. A, Spherical clusters of Dcx-positive neuroblasts (n = 6) are at some distance from the PECAM-1-positive vascular endothelial cells. B, C, Chains of neuroblasts (n = 12) wind around the vascular endothelial cells. Note that this chain appears to extend toward the injured region (on the right, in this figure) and to be connected with a spherical cluster of neuroblasts that is not associated with blood vessels. See also supplemental movie 1 (available at www.jneurosci.org as supplemental material). Arrowheads, Spherical cluster of neuroblasts; arrows, elongated chain-like aggregate of neuroblasts. LV, Lateral ventricle. Scale bars, 20 μm. D, The chains were classified on the basis of their dorsoventral (d-v) and mediolateral (m-l) orientations. d, Dorsal; v, ventral; m, medial; l, lateral. E, F, The number of mediolaterally oriented chain-like neuroblasts (blue) was significantly larger than the number of dorsoventrally oriented neuroblasts (red). ∗p < 0.05 (χ² test). G, Dcx-stained semithin section of the striatum. The ectopic chain of neuroblasts in the electron micrograph in H is marked by arrowheads. H–K, Electron microscopic view of neuroblasts migrating within the striatum. H, Each Dcx-positive cell contains abundant lax chromatin, two to four small nucleoli, and a smooth scant cytoplasm, similar to neuroblasts in the SVZ. I, Dcx-positive neuroblasts are located close to blood vessels. Asterisks, Blood vessels. The boxed areas in I indicate the fields shown in J and K. Scale bar, 2 μm. J, Dcx-positive neuroblasts are adjacent to the thin processes of astrocytes (arrowhead) associated with endothelial cells (arrow) of blood vessels. Asterisks, Cytoplasm of Dcx-positive neuroblasts. Scale bar, 500 nm. K, A zonula-adherens-like contact (arrowhead) is observed between two Dcx-positive neuroblasts. Scale bar, 500 nm.