Anti-inflammatory effects of ciprofloxacin in S. aureus Newman induced nasal inflammation in vitro

OBJECTIVES: Chronic rhinosinusitis (CRS) is a chronic inflammatory disease of the nasal mucosa. Recent studies suggest that S. aureus enterotoxins may play an etiologic role in the development of CRS. Apart from surgery and repeated courses of steroids, macrolide antibiotics have been reported to exert anti-inflammatory effects in CRS. Similar effects have been reported for fluoroquinolones on various cell types. Since these effects have poorly been characterized in CRS, we examined anti-inflammatory effects of ciprofloxacin on human nasal epithelial cells (HNECs). METHODS: Inflammation was induced in HNECs cultured from nasal turbinate mucosa with supernatants of S. aureus Newman for 12 hours. Subsequently, HNECs were coincubated with S. aureus Newman and ciprofloxacin (1.5 × 10(-5 )M), clarithromycin (10(-6 )M) or prednisolone (10(-5 )M) for another 12 hours. IL-8 synthesis was quantified after 12 and 24 hours by ELISA. RESULTS: Stimulation with S. aureus Newman supernatants was associated with an increase of IL-8 synthesis after 12 hours in all experiments. During the second 12 hours, IL-8 synthesis decreased and this effect was independent from any stimulus or inhibitor. However, coincubation of HNECs with ciprofloxacin was associated with a more extensive decrease of IL-8 synthesis. Similarly, addition of clarithromycin was associated with a reduction of IL-8 synthesis although this effect was not significant. Coincubation with prednisolone resulted in a significant reduction of IL-8 levels. CONCLUSION: Ciprofloxacin exerts anti-inflammatory effects in S. aureus Newman driven nasal inflammation. Inhibitory effects were comparable to those of prednisolone and clarithromycin.