[Go to this article.]

Figure 3
Abnormalities of vascular structure and gene expression in RAMP2^–/– embryos. (A–H) Vascular structure of WT and RAMP2^–/– embryos. Transmission electron micrographs of vitelline arteries (A and B), hepatic vessels (C and D), and aortas (E and F) from E12.5 RAMP2^–/– and WT embryos. The vitelline arteries and hepatic vessels from RAMP2^–/– mice showed the detachment of ECs (E) from basement membrane (arrows, B and D). In aortas from RAMP2^–/– mice, the smooth muscle cell layer was thinner and rougher than in aortas from WT mice (double-headed arrows, E and F). (G and H) Immunohistochemical staining for type IV collagen and actin in aortas from WT and RAMP2^–/– mice. Green, immunohistochemical staining using anti–mouse type IV collagen antibody; red, phalloidin (actin); blue, DAPI (nuclei). The structure of the smooth muscle cell layer and the basement membrane showed severe deformity in RAMP2^–/– mice. (I) Quantitative real-time PCR analysis of gene expression in the umbilical artery from E13.5 embryos. Expression levels are shown relative to the level in WT embryos. VE-cadherin, CDN5, and α2 type IV collagen (COL4A2) expression was reduced in arteries from RAMP2^–/– mice. n = 6 per group. *P < 0.05, **P < 0.01 vs. WT. Scale bars: 2 μm (A–D); 25 μm (E–H).