Figure 6. Intact alignment of luminal epithelium surrounding the embryo is associated with failed embryo invasion in Hif2a-uKO mice.

(A) Alignment of luminal epithelium disappeared at the implantation site, and trophoblast invasion started in the control mice at 2100 hours on day 5. In contrast, alignment of luminal epithelium was intact at the implantation site, and trophoblast invasion did not occur in Hif2a-uKO mice at the same time. On day 6 morning, destroyed embryo with blood cell infiltration was observed at the implantation site of Hif2a-uKO mice, while the stromal area with trophoblast invasion expanded in the controls. Scale bar, 200 μm; arrowhead, an embryo; s, stroma; le, luminal epithelium; arrow, a destroyed embryo with blood cell infiltration. (B) Expression of E-cadherin, a tight junction regulator as well as a marker of epithelium, was eliminated and epithelial alignment was collapsed at implantation sites of the controls, while both E-cadherin expression and epithelial alignment were persistent in Hif2a-uKO mice on day 5 evening.