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. 2012 Oct 24;7(10):e48001. doi: 10.1371/journal.pone.0048001

Figure 1. Close interactions between astrocytic processes and blood vessels in the early postnatal mouse cortex.

Figure 1

(A–C) Limited interactions between the cell body of young astrocytes and blood vessels in the mouse cortex at P5. Blood vessels were stained using isolectin B4 (IB4, green in A & C), while young astrocytes were labeled using anti-BLBP antibodies (red in B & C). Limited overlap was observed between IB4 and BLBP staining. (D–F) Close interactions between astrocytic processes and blood vessel in the mouse cortex at P7. An mTomato/mEGFP reporter line was used to labeled astrocytes by nestin-creER mediated recombination induced at E18.0. A sporadic number of astrocyes and their processes were labeled by expression of mEGFP (green in E & F), while blood vessels continued to express a strong level of mTomato (red in D & F). The vast majorities of labeled astrocytes contact blood vessels though their processes (arrowheads in F). Also note green autofluorescence in blood vessels, which does not stain positive for anti-GFP antibodies. (G–I) Confocal microscopy analysis of mEGFP (green in G & I) and BLBP (blue in H & I) staining of brain sections as in (D–F). Each of the mEGFP positive cells overlaps with a single BLBP positive cell body (arrowheads in H & I), indicating that mEGFP positive cells are astrocytes. (J–L) Interactions between astrocytic processes and blood vessels examined by 3-D confocal reconstruction. Astrocytic processed are labeled by mEGFP (green). Blood vessels are labeled by mTomato (red). An astrocyte approaches from the left side and interact extensively with a blood vessel, with some processes wrapping around the vessel and interacting from the opposite side. A montage of selected Z-images is shown in (J), Z-projection in (K), and XY, XZ, and YZ cross-sections in (L). (M) Cross-sections of 3-D reconstruction of a second astrocyte that show clear interactions of individual astrocytic endfeet with a blood vessel. See supplemental information for movies of the 3-D reconstruction. Scale bar in (A), 200 μm for (A–C) and 100 for μm (D–I).