Evaluation of media for cell differentiation in a nasal mucosa model based on the epithelial cell line Cl-pNaEC for preclinical drug testing

The reliable transferability of preclinical testing is crucial for reducing cost and time in the implementation of new active substances and formulations. Therefore, in vitro models can replace animal testing, if the model is reliable, fully characterized and able to replicate the physiological characteristics accurately. Recently, the porcine nasal epithelial cell line CI-pNaEC was introduced as a candidate for a suitable in vitro model of nasal mucosa, as it shows mucociliary differentiation and appropriate permeation properties. In this study, CI-pNaEC was exposed to seven commercially available culture media (huNASA, PneumaCult, BEGM, BEpiCM, LHC-9, AECGM and mAir) at air-liquid interface and tissue-specific differentiation of the resulting nasal mucosa models was evaluated in terms of histology, mucus quality and quantity, barrier properties and ciliation. Mucus expression was analyzed quantitatively and the mucus diffusion barrier was studied using fluorescence recovery after photobleaching. Epithelial barrier formation was tested by determination of transepithelial electrical resistance and permeation studies using marker molecules. Differentiation of ciliated cells was studied microscopically and using immunostaining method. For huNASA and PneumaCult, features that closely mirror the in vivo characteristics of nasal epithelium such as abundant mucus expression and ciliation were expressed. In contrast, BEpiCM and mAir cultures showed diminished mucus production and reduced ciliation, while nasal mucosa constructs cultivated in BEGM, LHC-9, and AECGM exhibited only minimal mucus expression, no ciliation, and markedly higher barrier resistance. The study demonstrates a clear impact of the culture media examined on the expression of tissue-specific characteristics and thus on the suitability of the constructs as alternatives to animal testing, with huNASA and PneumaCult appearing to be the more suitable media.