Purpose: To evaluate the feasibility of using a serially passaged culture of human nasal epithelial cell monolayers on a permeable support for in vitro drug transport studies. The optimum conditions for passaged culture as well as the correlation between the transepithelial electrical resistance (TEER) value and drug permeability (Papp) were evaluated.
Methods: Fresh human nasal epithelial cells were collected from normal inferior turbinates and were subcultured repeatedly in serum-free bronchial epithelial cell growth media (BEGM) in petri dishes. The subcultured cells of each passage were seeded onto permeable supports at 5 x 10(5) cells/cm2 and grown in Dulbecco's modified Eagle medium (DMEM). Morphologic characteristics were observed by scanning electron microscopy (SEM). To verify the formation of tight junctions, actin staining and transmission electron microscopy (TEM) studies were conducted. In the drug transport study, [14C]mannitol and budesonide were selected as the paracellular and the transcellular route markers, respectively.
Results: Serially passaged cells were successfully cultured on a permeable support and showed significantly high TEER values up to passage 4. After 14 days of seeding, SEM showed microvilli, and protrusions of cilia and mucin granules were detected by TEM. The paracellular marker [14C]mannitol showed a nearly constant permeability coefficient (Papp) when the TEER value exceeded 500 omega x cm2 regardless of the passage number. However, as expected, budesonide showed a higher permeability coefficient compared to [14C]mannitol and was less affected by the TEER value.
Conclusions: Human nasal epithelial cell monolayers were successfully subcultured on a permeable support up to passage 4. These cell culture methods may be useful in high-throughput screening of in vitro nasal transport studies of various drugs.