Effect of oleoresin capsicum (OC) and ortho-chlorobenzylidene malononitrile (CS) on ciliary beat frequency

Tear gases are largely used to control civil unrest. Their incapaciting effects involve the eyes, skin, and respiratory tract. We aimed to evaluate the effects of ortho-chlorobenzylidene malononitrile (CS) and oleoresin capsicum (OC) on ciliary beat frequency (CBF) of mouse tracheal rings. Addition of 0.05% OC or 0.01% CS induced a progressive decrease in CBF, from 11.5 +/- 0.5 to 4 +/- 0.1 Hz (P < 0.05) and from 12.5 +/- 0.5 to 2.5 +/- 0.1 Hz (P < 0.05), respectively, 30 min after exposure to the tear gas. Addition of exogenous ATP inhibited the effect of OC, suggesting that ATP could be used to counteract these adverse effects on CBF. However, ATP was inefficient against CS. Methylene blue and H7 inhibited the effects of OC, whereas indomethacin had no effect. None of these drugs affected the inhibitory action of CS. These results suggest that the inhibitory effect of OC is mediated through the guanylate cyclase-dependant pathway or protein kinase C-dependent phosphorylation. Another mechanism is probably involved in CS-induced inhibitory effect. Histological analysis of the trachea revealed an increase in mucus secretion after exposure to OC, and cytoplasmic vacuoles in epithelial cells after exposure to CS. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.