Establishment of an in Vitro Model of the Human Placental Barrier by Placenta Slice Culture and Ussing Chamber

Our purpose was to establish an in vitro model of the human placental barrier based on placenta slice culture and Ussing chamber. The villous morphology, beta-human chorionic gonadotropin (beta-hCG), mRNA and efflux function of P-glycoprotein (P-gp), and the permeability of the fluorescent marker were confirmed. The results showed that syncytiotrophoblast cells with abundant endoplasmic reticulum and mitochondria were covered with a dense microvillus in the placenta slice. The beta-hCG secretion levels in the Ussing chamber were 274.13 +/- 13.52 mIU/mL at 5 h, significantly higher than that in the incubator 95.2 +/- 13.14 mIU/mL, and beta-hCG continued to secrete for 48 h. P-gp mRNA was expressed in the placenta slice. The Rho123 apparent permeability coefficient (Papp) value from maternal side to the fetal side was 26.34 +/- 1.87 nm/s, but it was significantly increased, to 289.55 +/- 6.02 nm/s after adding verapamil. The Rho123 efflux value was >2. The fluorescein Papp value was (3.42 +/- 0.24) x 10(-3) nm/s. In contrast, the fluorescein isothiocyanate-dextran (FD70) Papp value was (3.93 +/- 0.08) x 10(-5) nm/s. This indicates that the placenta slice in the Ussing chamber had the activity of a placenta, and can act as a valuable in vitro model of placental barrier.