<p>Representative vWF-stained histological sections of the defect site of male rats treated with BG40 (A, n = 6) and BG40+EPC (B, n = 6). The blood vessel density increased significantly in animals treated with BG40+EPC, compared to BG40 alone (B). vWF-positive structures appear brown (arrows). The isotype control is presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0079058#pone-0079058-g006" target="_blank">figure 6C</a>. The absence of staining in blood vessel structure (arrows) indicates the specificity of the vWF-staining (C). An overview of the defect area is provided in d (original magnification 50x). The BG40 implant could not be preserved during sample sectioning and left a gap corresponding to the BG area (defect site). The skull bone is located in the right corner (skull). The encircled area marks the region shown at higher magnification (original magnification 200x) in (A) and (B). The quantitative evaluation of vWF-positive blood vessel structures is depicted in (e). All vWF-positive, blood vessel like structures in the neighborhood of the whole defect site were counted. Red scale bars: 100 µm (A, B, C), 500 µm (D), *: p = 0.015.</p
