Similar effect of lidocaine and saline on ciliary beating of nasal epithelial cells in vitro

Rationale: Primary ciliary dyskinesia is a rare genetic disease affecting ciliary motility and causing respiratory symptoms. Diagnosis can be done by high-speed-videomicroscopy using nasal epithelial cells (NECs) obtained via brushings. This procedure can be painful, especially for children. The use of lidocaine is proposed to reduce this pain; however, it is not clear whether lidocaine changes ciliary beating frequency (CBF) or pattern (CBP) in the subsequent high-speed-videomicroscopy. Objective: The aim of this study was to analyse the effect of lidocaine on the CBF and the CBP of differentiated, air-liquid-interface cultured NECs. Methods: NECs from healthy volunteers were obtained via brushings and cultured at the air-liquid-interface. After differentiation, lidocaine or isotonic saline (IS, control) were added apically for 1 or 5 min each and CBF (in top view of whole inserts and side views of scratched cells) and CBP (only side view) were assessed and recorded up to 150 min. CBF was computed and CBP was analysed semiquantitatively. Results: Lidocaine as well as IS increased the CBF in the top view approach significantly compared to baseline. However, we found no significant differences between lidocaine and IS (control) treatment. Additionally, no effect of lidocaine on CBF, CBP, amplitude, inter- and intracellular coordination or transport was seen in the side view approach. Conclusion: We conclude that the observed CBF increase is related to the addition of liquid on the mucus layer and not by the lidocaine itself. Therefore, it seems possible to use lidocaine for nasal analgesia without impact on subsequent analysis of the ciliary motility.