Cells were isolated from the chorionic villi tissue of the placenta.
Chorionic villi-related tissue was removed, washed with PBS and minced. The resulting tissue segments were plated on a culture dish in Dulbecco’s Modified Eagle Medium (DMEM), supplemented with fetal bovine serum (FBS, 10%), β-mercaptoethanol (0.1 mM), nonessential amino acids (1% ), and antibiotics. After 5 days in culture, unattached particles were removed by pipetting. When the cells that grew out of the tissue segments became 90% confluent, they were transferred to a larger dish (75 cm2). When the cells reached approximately 90% confluency, the culture was designated passage 1 (p1).