In vivo effects of citric acid/zwitterionic surfactant cleansing solution on rabbit sinus mucosa

Background: Chronic rhinosinusitis that is refractory to medical or surgical intervention may involve a particularly resistant form of infection known as a bacterial biofilm that is recalcitrant to antibiotics secondary to physical barrier characteristics. Recently, a novel sinus cleansing solution, citric acid/zwitterionic surfactant (CAZS) was shown to be extremely effective in disrupting biofilms in vitro. The purpose of this study was to determine the effects of CAZS on sinonasal epithelium in vivo compared with normal saline. Methods: Indwelling catheters were placed into the right maxillary sinus of New Zealand white rabbits. CAZS solution or normal saline (10 mL) was instilled at a rate of 20 mL/minute into the sinus followed by aspiration. Rabbits were killed 1, 3, and 6 days after treatment. Mucosa from both maxillary sinuses was harvested and evaluated for physiological activity (ciliary beating) as well as morphological integrity of the epithelium by scanning electron microscopy. Results: One day after treatment, beating cilia was evident with morphological analysis shown intact epithelium with 80-85% denudation of cilia compared with saline. Three days after treatment, ciliary activity was again noted with morphological evidence of persistent denuded cilia. By day 6 after treatment, the epithelium had regenerated cilia over the apical surface. Throughout the recovery period beating cilia was evident in CAZS-treated sinuses. Conclusion: This study shows that although CAZS acutely denudes respiratory cilia, the remaining cilia are active. Additionally, the epithelial barrier appears intact with active ciliogenesis, and reciliation of the mucosal surface occurring 6 days after treatment.