Protective barrier properties of Rhinosectan® spray (containing xyloglucan) on an organotypic 3D airway tissue model (MucilAir): results of an in vitro study

BACKGROUND To evaluate barrier protective properties of Rhinosectan® spray, a medical device containing xyloglucan, on nasal epithelial cells (MucilAir). METHODS MucilAir-Nasal, a three-dimensional organotypic (with different cell types) airway tissue model, was treated with the medical device Rhinosectan® (30 µL) or with controls (Rhinocort-budesonide-or saline solution). The protective barrier effects of Rhinosectan® were evaluated by: TEER (trans-epithelial electrical resistance) (preservation of tight junctions), Lucifer Yellow assay (preservation of paracellular flux) and confocal immunofluorescence microscopy (localization of tight junction proteins). RESULTS Exposure of MucilAir with Rhinosectan® protected cell tight junctions (increases in TEER of 13.1% vs -6.3% with saline solution after 1 h of exposure), and preserved the paracellular flux, even after exposure with pro-inflammatory compounds (TNF-α and LPS from Pseudomonas aeruginosa 10). Results of confocal immunofluorescence microscopy demonstrated that, after treatment with the pro-inflammatory mixture, Rhinosectan® produced a slight relocation of zona occludens-1 in the cytosol compartment (while Rhinocort induced expression of zona-occludens-1), maintaining the localization of occludin (similarly to negative control). CONCLUSIONS Results of our study indicates that Rhinosectan® creates a protective physical barrier on nasal epithelial cells in vitro, allowing the avoidance of allergens and triggering factors, thus confirming the utility of this medical device in the management of nasal respiratory diseases, as rhinitis or rhinosinusitis.