An In Vitro Model for the Study of Human Implantation

Problem Implantation remains the rate-limiting step for the success of in vitro fertilization. Appropriate models to study the molecular aspects of human implantation are necessary in order to improve fertility. Methods First trimester trophoblast cells are differentiated into blastocyst-like spheroids (BLS) by culturing them in low attachment plates. Immortalized human endometrial stromal cells and epithelial cells (ECC-1) were stably transfected with GFP or tdTomato. Co-culture experiments were monitored using Volocity imaging analysis system. Results This method demonstrates attachment and invasion of BLS, formed by trophoblast cells, into stromal cells, but not to uterine epithelial cells. Conclusion We have developed an in vitro model of uterine implantation. The manipulation of this system allows for dual color monitoring of the cells over time. Additionally, specific compounds can be added to the culture media to test how this may affect implantation and invasion. This model is a helpful tool in understanding the complexity of human implantation.