Establishment Of A Three-dimensional Model Of Embryo Implantation In Vitro And Study Of The Affecting Factors On Uterine Receptivity

In mammals, blastocyst implantation is the process by which the fertilized ovum, which has developed to the hatched blastocyst stage, becomes intimately connected to the maternal tissue in the uterus. Synchronous development of embryo and endometrium is a prerequisite for blastocyst implantation. Specific mechanisms regulating embryo implantation remain undefined. Several culture systems have been used to study various aspects of mammalian endometrial metabolism and embryo-endometrial interactions. However, none of these culture systems in vitro fully imitates the normal structure and function of the endometrium in vivo. Previous studies on endometrial epithelial monolayers in contact with the embryo have given information only about the attachment of the embryo. As normal implantation is considered to be an active process involving both trophoblastic cells and cells of the endometrium, it is questionable whether observations on in vitro implantation reflect the true situation in vivo. To study implantation, it is important to have a polarized epithelium with well-developed intercellular junctions that rest on a basement membrane. Furthermore, it is crucial to have a three- dimensional stromal compartment with both extracellular matrix and stromal cells, since interactions between epithelium and the underlying stromal cesss are essential for the function of the endometrium. The object of the study was to establish a model in vitro that imitates the normal receptible endometrium in vivo. We also have observed the effects of E2, embryo and cytokines on regulating uterine receptivity using the established model to explore the specific mechanism of embryo implantation.Section â… Establishment of a three-dimensional model of endometrium in vitroâ… -1 Co-culture of luminal epithelial and stromal cells of mouse receptible endometriumObjectives: To establish an ideal three-dimensional model of endometrium in dual-chambered system in vitro.Methods: A three-dimensional model with separated endometrial epithelial andstromal cells was established using dual-chambered system. The cultures were evaluated by light microscopy and scanning and transmission electron microscopy. Immunohistochemical staining for cytokeratin and desmin confirmed the origin of endometrial cells.Results: The cell separation and isolation methods yielded UEC and USC culture that were greater than 90%, as assessed by cell immumohistochemistry. Scanning electron microscopy revealed a confluent epithelium with an abundance of microvilli and pinopodes on the apical surface. Transmission electron microscopy indicated a polarized columnar epithelium in monolayer with basally nuclei and tight junction. Conclusion: This model represents a three-dimensional system that imitates the normal endometrium. â… -2 The study on three-dimensional recontruction of endometrium in vitroObjectives: To develop a method to establish a three-dimensional in vitro model system of endometrium using tissue engineering methed. Methods: The endometrial cells were cultured on a biodegradable hybrid Collagen-PGLA polymer mesh and observed by scanning electron microscopy and light microscopy. Results: It showed that the endometrial cells adhered and spread well on the surfaces of the collagen sponge of the hybrid mesh after being cultured for 5 days. After 2 weeks, the cells proliferated to become completely connected in a layer structure.Conclusion: The three-dimensional model of endometrium could be established using the hybrid polymer mesh as a skeleton in vitro.Sectionâ…¡Study of the mechanism of uterine receptivity on a three-dimensional implantation model in vitroâ…¡-1 Embryonic regulation of uterin receptivity in mice endometrial cell in vitroObjectives: Synchronous development of embryo and endometrium is a prerequisite for blastocyst implantation. The purpose of the study was to study the effect of embryos on the establishment of uterin receptivity in three-dimensional model.