Doctoral Student Chungnam National University Chungnam National University, Republic of Korea
Abstract: The endometrium is the lining of the uterus that develops and regresses in response to changes in female hormone secretion during the reproductive cycle, playing a critical role in embryo implantation and successful pregnancy. Similar to many mammalian species, the canine endometrium undergoes regular cyclical changes, including growth, differentiation, remodeling, destruction, and repair. This study compared the characterization and gene expression of endometrial stem cells (EnSCs) and EnSC-derived extracellular vesicles (EVs) during the estrous cycle (diestrus and estrus). Genetically identical cloned dogs were used to allow a precise comparison of mesenchymal stem cell (MSC) activation, characteristics, and EVs secretion during different stages of the estrous cycle. The estrous cycle stages were confirmed through vaginal smears and estrogen level measurements, and uterine tissues were collected during neutering surgeries. Cell counts were compared between tissues collected from estrous and diestrus endometrium of the same weight, and cell morphology was observed. Each isolated particle was characterized by analyzing the expression of three lineage differentiation markers and MSC-specific markers to compare their properties. Additionally, EVs derived from estrous and quiescent EnSCs were extracted and their properties were compared. As a result, we identified differences in the efficiency of isolating cells from endometrial tissue at different stages of the estrous cycle, changes in cell morphology, and distinct miRNA expression profiles in EVs derived from EnSCs during the estrus and diestrus stages. These findings provide a deeper understanding of the interplay between stem cells, their secretions, and hormonal cycles, with applications in fertility treatment, uterine repair, and regenerative medicine.
Funding Source: This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (grant number: HI22C1754).
