Usage of human endometrial mesenchymal stem cells in in vitro implantation model

To establish an in vitro implantation model using endometrial W5C5+ mesenchymal stem cells and mouse blastocysts as a surrogate embryo this study was designed. The W5C5+ mesenchymal stem cells were isolated from human endometrial cell suspension (ECS) at 4th passage by magnetic activated cell sorting method. ECS and W5C5+ cells were separately co-cultured with human myometrial muscle cells for five days. After collection of mouse blastocysts, the embryos were transferred on the top of co-cultured cells for 48 hrs. The interaction of embryo and cultured cells was assessed by morphological and ultrastructural evaluations and analysis of the expression of genes related to implantation (αV and β3 integrins, interleukin-1 receptor; IL-1R, leukemia inhibitory factor; LIF and leukemia inhibitory factor receptor; LIFR). The micrographs showed trophoblastic cells were outgrowth around the embryonic cells and they attached to the ECS and W5C5+ cells. Ultrastructural observation revealed the appearance of pinopode and microvilli-like structures on the surfaces of both ECS and W5C5+ endometrial cells.In addition the embryos were developed to egg-cylinder stage in two groups. The analysis of genes expression showed no significant differences in genes expression in both groups in the presence of embryo but an increased expression of αV was detected in W5C5+ cells in comparison with ECS cells in the absence of embryo. Thus, this study showed W5C5+ cells during co-culture with smooth muscle cells could be differentiated to epithelial-like cells and interacted with mouse embryo and this co-cultured cells has a potential as an implantation model.