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. 2018 Nov 5;11:402. doi: 10.3389/fnmol.2018.00402

Figure 4.

Figure 4

Ultrastructural analysis of PDGFR-β-positive cells associated with the vasculature in the lesioned striatum at days 3 and 7 after 3-NP injection. (A–C) At 3 days post-lesion, PDGFR-β-positive cells are characterized by large euchromatic nuclei and cytoplasmic distention, with dilated cisternae of rough endoplasmic reticulum (rER, #). Note that PDGFR-β-positive cells are located on the abluminal side of smooth muscle cells (SM) in venules (A) and arterioles (B,C). (C) A higher magnification image of the boxed area in (B), showing that PDGFR-β-positive processes form a multilayered sheath that covers the smooth muscle (SM) cells completely. (D) PDGFR-β immunoreactivity is not detected in endothelial cells (EN) and pericytes (P) of capillaries. The magenta-colored structures (as in A,D) indicate the degenerating glial limitans. (E) PDGFR-β-positive cells that have large euchromatic nuclei with prominent nucleoli (close arrowheads) extend long cytoplasmic processes (open arrowheads) that are apposed to the capillaries. Arrows indicate the pericyte processes. M, macrophage. (F,G) At day 7, PDGFR-β-positive cells are localized on the abluminal side of a smooth muscle (SM) cell and endothelial cells (EN). (G) A higher magnification image of the boxed area in (F), showing that PDGFR-β-positive processes are closely associated with bundles of collagen fibrils (asterisks in G). (H) A part of a PDGFR-β-positive cell with a dilated rER showing a membrane-bound granule with filamentous contents (asterisk). (I–M) PDGFR-β-positive cells and processes appear to wrap around or directly abut the abluminal surface of endothelial cells (EN) and pericytes (P) of capillaries (c). Note that PDGFR-β-positive cells have large euchromatic nuclei with prominent nucleoli (arrowhead in G) and well-developed rER. (inset in J,M) Higher magnification images of the boxed areas in (J,L), respectively, showing that PDGFR-β-positive cells and processes are clearly segregated by the bl of the pericytes that envelop the endothelial cells. Note that PDGFR-β-positive cells are closely associated with bundles of collagen fibrils (asterisks in M). Light blue indicates endothelium in (B,K,L), yellow in (B,K,L) indicates the smooth muscle cell layer (B) and pericytes (K,L), respectively; orange indicates collagen fibril deposition in (L), and green indicates PDGFR-β-positive cells in (B,L). # in (H,I,J,K,M) indicate the dilated rER with dilated interconnecting cisternae. Scale bars = 2 μm for (B,D–F,I,J,L); 1 μm for (A,C,G,K,M); 0.5 μm for (H).