Figure 1.

A representative image of the cortical surface and parenchymal vasculature before and after 14 days of hypoxia in a Tie2-green fluorescent protein (GFP) mouse. (A) Cortical surface vasculature at prehypoxia. A wide field of view image of GFP-expressing vasculature captured with confocal laser scanning microscopy at prehypoxia (left) was used as a reference to track the target microvessels and astrocytes during the follow-up imaging experiments. The location shown in the green square, a peripheral region of the middle cerebral artery (MCA) territory (right), was imaged using two-photon microscopy (shown in B). (B) Parenchymal microvessels before (left) and after 14 days of hypoxia (right). The pial arteries (i.e., dense and thick endothelial cells) and veins (i.e., sparse and thin endothelial cells) slightly dilated after 14 days of hypoxia (top right) compared with prehypoxia (top left), whereas the parenchymal capillary diameters drastically increased after 14 days of hypoxia (bottom right) relative to prehypoxia (bottom left). For visual purposes, the image is presented with the maximum intensity projection over depths of 0 to 100 μm (top) and 100 to 300 μm (bottom) from the surface. The red color indicates blood plasma labeled with sulforhodamine 101 (SR101) (plasma-SR101), and green color is GFP-expressing endothelial cells (Tie2-GFP).