Figure 11.

Schematic representation of dynamic PDGFR-β-positive cells in the lesion core in striata treated with 3-NP. (A) In the saline-treated control striatum, PDGFR-β-positive cells with thin processes are associated with larger caliber vessels having one or two layers of smooth muscle cells. These cells are located outside the smooth muscle cells and are surrounded by the glia limitans of astroglial processes. (B) At 3–7 days post-lesion, PDGFR-β-positive cells are highly proliferative and express nestin and vimentin. They have large euchromatic nuclei and dilated cisternae of rER, indicating the presence of active collagen synthesis. They also migrated to the adjacent microvascular wall and wrap around or directly abut the abluminal surface of endothelial cells or pericytes, despite the ongoing association with the vasculature. (C) At 14–28 days, the lesion core is progressively infiltrated by migrating PDGFR-β-positive cells expressing nestin and vimentin. They have highly branched cytoplasmic processes that are frequently in close apposition or are even interwoven with each other, forming a network. In addition, PDGFR-β-positive somata and processes have close apposition with brain macrophages, nearly always at the branch points of distal processes.