Effects of beta-toxin of Staphylococcus aureus and Neuraminidase of Streptococcus pneumoniae on Ciliary Activity of Nasal Ciliated Epithelial Cells

ABSTRACT

BACKGROUND AND OBJECTIVES: The in vitro effects of pneumococcal neuraminidase and staphylococcal beta-toxin on ciliary activity were investigated at different concentrations and lengths of exposure. MATERIALS AND METHODS: The ciliated epithelial cells were taken from the maxillary sinus mucosa of rabbits. Ciliary beat frequency (CBF) was measured at concentrations of 0.01, 0.1 and 1.0 U/mL of neuraminidase and 0.1, 1.0, 2.0, 5.0 and 10 U/mL of beta-toxin using a video-computerized analysis technique. The CBF was measured 2, 4, 6, 12, 24 and 48 hours after administration of the neuraminidase and beta-toxin. In the control group, normal saline was percutaneously applied to the right maxillary sinus. In the experimental group, 2 U/mL of beta- toxin was applied to the left maxillary sinus using the same technique. At 7 days, all of the mucosae were taken from the inferomedial wall of the maxillary sinus for light microscopy. RESULTS: There was no change in CBF during a 48-hour incubation at 0.01, 0.1 and 1.0 U/mL of neuraminidase. However, the CBF dropped significantly after an 8-hour incubation at 2.0 U/mL of beta-toxin (p<0.05, repeated measures ANOVA). No ciliary activity was observed after a 12-hour incubation at 10 U/mL of beta-toxin. The mucoid, purulent discharge was observed in the maxillary sinuses of the experimental group. Prominent epithelial disruption and infiltration of inflammatory cells into the epithelium and lamina propria were observed in the beta-toxin-applied group. CONCLUSION: The results of this study suggest that staphylococcal beta-toxin may reduce ciliary activity and induce sinusitis without occlusion of the natural ostium of the maxillary sinus in rabbits. This study provides another animal model of sinusitis for understanding the pathogenesis of sinusitis caused by bacterial exotoxins.