Development of blood-cerebrospinal fluid barrier model expressing pharmaceutically important transporters.

We have established and optimized a protocol for the high-yield isolation of primary epithelial cells from rat choroid plexus. The addition of cytosine arabinoside suppressed the growth of contaminating cells, and epithelial culture was grown into a confluent impermeable monolayer within 5-6 days after seeding. To form an in vitro blood-CSF barrier, epithelial cells were plated on inverted coated polycarbonate support of Transwell inserts. Morphologically, the polarized cells remained cuboidal in shape and expressed TJ proteins at a high rate. The filter-grown monolayers displayed transendothelial resistance (TEER) values in the range of 160 to 180 {Omega} x cm2 and remained at this level for 3 days, indicating the persistent formation of continuous TJs. The cells were able to secrete cerebrospinal fluid (CSF) actively. Epithelial cells showed expression of selective influx and efflux transporters. To conclude, our BCSFB model exhibits tight, functional barrier characteristics and shows the functional expression of the pharmaceutically important influx/efflux transporters. The recent model is suitable for in vitro investigations of BCSFB and routine pre-clinical drug discovery.