Vascularization of placenta in WT, <i>Vash1^(−/−)</i>, and <i>Vash2^(−/−)</i> mice.

<p>Upper panels show vascular morphogenesis. The triple staining with tomato lectin (green), anti-CD31 (blue), and anti-type IV collagen (red) was performed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0104728#s2" target="_blank">Materials and Methods</a>. Tomato lectin identified the maternal blood vessels; and CD31-positive structures, the fetal blood vessels. The presence of type IV collagen indicated the basement membrane. Bar = 50 µm. Lower graph on the left show the fetal vascular area, and that on the right shows the maternal vascular area determined for WT (N = 5), <i>Vash1^(−/−)</i> (N = 3), and <i>Vash2^(−/−)</i> (N = 3) placentas. Ten 400× fields per placenta were used for quantification. *P<0.01.