Figure 4

VEGFR-1, CD31, and F4/80 in the post-implantation mouse uterus. IHC and double staining IF were performed on E6.5 frontal uterine sections. (A) Schematic representation of an E6.5 mouse uterus showing the embryo (e), anti-mesometrial (am) and mesometrial (m) areas, and myometrium (myo). (B) CD31⁺ ECs (brown) are abundant in the decidua around the implanted embryo and the myometrium. (C) A majority of F4/80⁺ macrophages (green) are observed in the secondary decidual zone (SDZ) and myometrium. (D) A majority of VEGFR-1⁺ cells (brown) are observed in the primary decidual zone (PDZ) directly adjacent to the implanted embryo. (E-F) Double staining of VEGFR-1 (red) and CD31⁺ (green) demonstrates (E) co-expression in the ECs within the PDZ (inset), (F, G) and minimal co-expression of VEGFR-1 and CD31 in the abundant ECs in the SDZ of the anti-mesometrial and mesometrial poles. (H) Double staining for VEGFR-1 (red) and F4/80⁺ (green) shows VEGFR-1⁺ cells adjacent to F4/80⁺ macrophages in the PDZ (inset). (I, J) F4/80⁺ macrophages are abundant in the SDZ of the anti-mesometrial pole and mesometrial poles, where VEGFR-1 expression is low to absent. (B-D, H) Scale bars = 100 μm. (F, G, I, J) Scale bars = 50 μm.