Effect Of Shear Stress On The Migration Of Human Villous Trophoblast Cells

During the pregnancy of mammalians, trophoblast cells (TCs) play an important part in implantation and formation of placenta: TCs enter endometrium firstly, then invade the endometrial capillaries, migrate within the uterine vasculature, and eventually reside in the spiral arteries of the uterus. After that, those intravascular TCs remodel the spiral arteries to ensure enough blood supplies to the fetal. Evidently, this migration process suggests that the migration of TCs is against the stream of blood flow. The present thesis project is to study the TC migration and elucidate the effect of shear stress on TCs'migration behavior in an in vitro setting.Object: To explore TCs'migration mechanisms and effective factors related in the reverse migration with the effect of fluid shear stress on the migration behavior of TCs, which were cultured alone or co-cultured with endothelial cells.Methods: Using mammals'cell primary culture techniques, the human embryonic villous trophoblast cells were isolated and cultured in vitro. Utilizing 2-D flow chamber technique, microscopic observation and image analysis software, the migration direction and velocity of TCs cultured alone or co-cultured with endothelial cells were observed and analyzed under different shear stresses.Results: First, a simple and stable protocol for human trophoblast cell culture and the co-cultured model between TCs and HUVECs were established. Then, the effect of the flow-induced shear stress on the migration of TCs cultured alone and co-cultured with HUVECs was studied. For the TCs cultured alone, no directional migration was observed in the absence of shear stress. However, in the presence of shear stress, the cells migrated in the direction of the flow stream, becoming more obviously so when shear stress level increased. The migration velocity of the TCs cultured alone increased with increasing shear stress. For TCs co-cultured with endothelial cells, the cells'migration behavior was somewhat different from that of the cells cultured alone. Their migration direction and velocity did not change significantly with shear stress.Conclusion: Both the flow-induced shear stress and the contact of TCs with ECs are important factors in the migration of trophoblast cells. They together can influence the direction and the velocity of the migration of TCs.