University of Hertfordshire

  • Victoria Hutter
  • Constanze Hilgendorf
  • Anne Cooper
  • Vanessa Zann
  • David Pritchard
  • Cynthia Bosquillon
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Original languageEnglish
Number of pages1
Publication statusPublished - 2011
EventISAM - Rotterdam, United Kingdom
Duration: 18 Jun 2011 → …


CountryUnited Kingdom
Period18/06/11 → …


Purpose: To evaluate the suitability of the rat airway epithelial cell line, RL65 as an in vitro model for permeability screening of inhaled drugs.
Methods: RL65 cells were grown on 12 well Transwell® inserts under different culture conditions. Morphology was characterised using histology and microscopy. Formation of functional tight junctions was verified by trans-epithelial electrical resistance (TEER) measurements, permeability of the paracellular marker 14C-mannitol and immunohistochemistry. The presence of P-glycloprotein (P-gp) was assessed by gene expression analysis and permeability studies with the established P-gp substrates 3H-digoxin and Rhodamine 123.
Results: RL65 cell layers were successfully cultured at an air-liquid interface for up to 21 days. They displayed morphological characteristics typical of the bronchial epithelium. TEER above 400 ohm.cm2 and 14C-mannitol permeability values below 2 x 10-6 cm/s were obtained after optimisation of the culture conditions. No asymmetric transport of 3H-digoxin or Rhodamine 123 was observed.
Conclusions: RL65 layers grown at an air-liquid interface offer a suitable rat respiratory in vitro model for permeability measurements with TEER values and 14C-mannitol permeability in the range of established human bronchial epithelial models. The presence of P-gp could not be confirmed under the culture conditions investigated. Evaluation of other drug transporter systems is required to further characterise the model.

ID: 824392