Fig. 6

Notch4 (N4) expression in endothelial cells and mural cells in the peri-implantation uterus. H&E and double staining IF of E3.5 (A – C) and E6.5 (D – F) uterine sections. Ovals indicate areas of the uteri magnified (B1, C1, E1, F1). (A) H&E at E3.5 highlighting the luminal epithelium (arrows), inner circular and outer longitudinal myometrium [dashed bracket (myo)], endometrial stroma (st) and serosa (s). (B, C) Notch4⁺ cells are observed throughout the stroma, myometrium and serosa. Low levels of Notch4 are detected in the luminal (arrows) and glandular epithelium (g). (B) Notch4 and CD31. Notch4 is expressed in CD31⁺ ECs in the endometrium (oval) and myometrium (box). (C) Notch4 and SMA. SMA labels smooth muscle cells in the myometrium and serosa and is not associated with cells expressing Notch4. (D) H&E at E6.5 highlighting the embryo (e), inter-implantation sites (i), and myometrium (myo). (E, F) Notch4⁺ cells are observed throughout the decidua and myometrium at E6.5. (E) Notch4 and CD31. Notch4 is expressed in CD31⁺ ECs in the decidua. (F) Notch4 and SMA. Notch4 is not associated with SMA⁺ smooth muscle cells in the myometrium and serosa. DAPI identifies all nuclei in IF images. am, anti-mesometrial; m, mesometrial. Bar in A and D =100 μm. Bar in B, C, E, and F = 500 μm. Bar in B1, C1, E1, and F1 = 50 μm.