B, Pre-implantation P4 treatment rescued the expression of MFG-E8 on day 5 of pregnancy in Rb1d/d uteri. Scale bar = 100μm. Blue signal, nuclei stained by DAPI; yellow signal, MFG-E8; le, luminal epithelium; s, stroma; arrowhead, embryo. C, Pre-implantation P4 treatment recovered the expression of pRIP3, a mediator of necroptosis, on day 5 of pregnancy in Rb1d/d uteri. Scale bar = 100μm; blue signal, nuclei stained by DAPI; purple signal, pRIP3; le, luminal epithelium; s, stroma; arrowhead, embryo. 