Effects of alpha-toxin of Staphylococcus aureus on the ciliary activity and ultrastructure of human nasal ciliated epithelial cells

Objective: The in vitro effects of staphylococcal alpha-toxin on ciliary ac tivity were investigated at different concentrations and exposure times. St udy Design: Ciliated epithelial cells of the sphenoid sinus were taken fi o m patients operated on for pituitary tumors. Video-computerized analysis te chnique and transmission electron microscopy were used to analyze the effec ts of the toxin on ciliary activity. Methods: Ciliary beat frequency (CBF) was measured in four different concentrations of alpha-toxin including 0,1, 1, 10, and 50 mu g/mL. CBF was measured at 2, 4, 6, 12, 24, and 48 hours a fter administration of the toxin, To observe reversibility of the reduced c iliary activity, after 24-hour incubation in the media containing 10 mu g/m L of alpha-toxin, the media were replaced with alpha-toxin-free media. The tissues were also processed for transmission electron microscopy to observe ultrastructural changes of the epithelial cells. Results: CBF increased si gnificantly at alpha-hour incubation and then decreased significantly after 12-hour incubation in 10 mu g/mL of alpha-toxin (P < .05, repeated-measure s ANOVA), The transmission electron microscopic findings showed mitochondri al swelling and a slight protrusion of the plasma membrane of the cilia, In toxin-free media, loss of ciliary activity was not recovered. Conclusions: CBF increased at first, but with increasing incubation time ciliary moveme nts decreased gradually and stopped eventually. This loss of CBF may be an irreversible change associated with ultrastructural changes in the mitochon dria and the plasma membrane of the cilia.