Insights into the single-cell transcriptome characteristics of porcine endometrium with embryo loss
Reproductive disorders are a concern in the pig industry.  Successful gestation processes are closely related to a suitable endometrial microenvironment, and the physiological mechanisms leading to failed pregnancy during the peri-implantation period remain unclear.  We constructed single-cell transcriptome profiles of peri-implantation embryo loss and successful gestation endometrial tissues, and identified 22 cell subpopulations, with epithelial and stromal cells being the predominant endometrial cell types.  The two tissues showed marked differences in cell type composition, especially among epithelial cell subpopulations.Overall, the present study revealed the molecular features of endometrial cell transcription in embryo-lost endometrial tissues, providing deeper insights into the endometrial microenvironment of reproductive disorders, which may inform the etiological, diagnostic, and therapeutic studies of reproductive disorders. Overall design: All experimental animals were three years old with a similar genetic background.  We selected a Yorkshire sow with an abortion experience and subsequent unsuccessful breeding with three consecutive artificial insemination matings that represented the sample of embryo loss (EL).  Another Yorkshire sow with successful artificial insemination was selected and gestated for 30 days, representing the sample of successful embryo implantation (EIS).  We defined the day of artificial insemination as day 0 of pregnancy and endometrial samples were collected from each uterine horn