Assessment of mTOR pathway molecules during implantation in rats

Mammalian target of rapamycin (mTOR) is a member of the PI3K/Akt/mTOR signaling pathway that participates in cell growth, proliferation, protein synthesis, transcription, angiogenesis, apoptosis and autophagy. We investigated the role of mTOR and other signaling molecules in the rat uterus during implantation. Female pregnant rats were divided into three groups: embryonic days (ED) 4.5, 5.5 and 6.5 according to vaginal smears. Immunohistochemical staining of mTORC1, mTORC2, IGF1, PI3K, pAkt1/2/3, ERK1 and pERK1/2 was performed on formalin fixed, paraffin embedded uterine tissue samples. pAkt1/2/3 and ERK1 also were analyzed using western blotting. We found that PI3K/Akt/mTOR and ERK/pERK were increased during the implantation period. Different amounts of mTORC1, mTORC2, IGF1, PI3K, pAKT1/2/3, ERK1 and pERK1/2 were expressed in luminal epithelium, decidual cells, embryoblast and trophoblast cells during implantation. We suggest that mTOR and associated signaling molecules may participate in implantation.