Proteomic alteration of endometrial tissues during secretion in polycystic ovary syndrome may affect endometrial receptivity

Embryo implantation is a complex developmental process that requires coordinated interactions among the embryo, endometrium, and the microenvironment of endometrium factors. Even though the impaired endometrial receptivity of patients with polycystic ovary syndrome (PCOS) is known, understanding of endometrial receptivity is limited. A proteomics study in three patients with PCOS and 3 fertile women was performed to understand the impaired endometrial receptivity in patients with PCOS during luteal phases. Through isobaric tags for relative and absolute quantitation (iTRAQ) analyses, we identified 232 unique proteins involved in the metabolism, inflammation, and cell adhesion molecules. Finally, our results suggested that energy metabolism can affect embryo implantation, whereas inflammation and cell adhesion molecules can affect both endometrial conversion and receptivity. Our results showed that endometrial receptive damage in patients with PCOS is not a single factor. It is caused by many proteins, pathways, systems, and abnormalities, which interact with each other and make endometrial receptive research more difficult.

Expression of galectin-3 in mouse endometrium and its effect during embryo implantation

This study investigated the expression pattern of galectin-3 (Gal-3) in mouse endometrium during early pregnancy and its function during embryo implantation. The expression of Gal-3 was measured at the mRNA level using real-time PCR and at the protein level using immunohistochemistry and Western blotting. The expression of Gal-3 mRNA and protein in the pregnant group was higher than in the non-pregnant group, and mRNA and protein expression reached their maximum levels on days 4 and 2, respectively. Immunohistochemistry results showed that Gal-3 protein presented in luminal epithelium and glandular epithelium and reached its maximum on days 6–8 and days 2–4 after pregnancy, respectively. The number of embryos implanted decreased substantially when Gal-3 was knocked down in mouse endometrium. In conclusion, increased Gal-3 expression after pregnancy is required for embryo implantation.