Distribution of green fluorescent protein (GFP)-labeled cells in the choroid of an adult albino α-SMA-GFP transgenic mouse.

<p>(<b>A</b>) Choroidal vasculature as visualized by confocal microscopy through the RPE cell layer in a sclerochoroidal flat-mount. GFP-positive perivascular mural cells are present in choroidal arteries (box 1), smaller secondary arterioles (box 2), and branching precapillary arterioles (box 3). (<b>B</b>) Labeling of the endothelial layer throughout the choroidal vasculature was achieved with systemic perfusion of the lipophilic dye DiI, which becomes incorporated into endothelial cell membranes. (<b>C</b>) Superposition of the GFP and DiI signals demonstrates the perivascular nature of GFP-positive cells in the choroid. Scale bar = 50 µm.