THE EFFECTS OF OXYMETAZOLINE ON LYSOZYME SECRETION FROM THE HUMAN NASAL-MUCOSA

Lysozyme is a protein secreted by nasal submucosal glands. Its secreti on is under cholinergic control. It is considered important in nasal d efence as it enzymatically hydrolyses peptidoglycan bonds in bacterial cell walls and has specific activity against Gram-positive bacteria i n vitro. Oxymetazoline is freely available as a non-prescription nasal decongestant. Some recent work has shown that it has no effect on his tamine-induced plasma exudation but little is known about its effects on glandular secretion. The current study is a randomized controlled s tudy that investigates the effect of topical oxymetazoline on the tota l protein and lysozyme content of nasal fluid. Thirty healthy voluntee rs were randomized to receive either a normal saline nasal spray (plac ebo) or an active spray of oxymetazoline, 0.05% (w/v) in saline. NAR w as assessed in all subjects using posterior rhinomanometry and nasal l avage before the application of the spray and again 10 min later. The results were analysed using non-parametric statistics. There was a sig nificant decrease in both the lysozyme and total protein content of na sal lavage after application of oxymetazoline when compared with place bo (p < 0.05). A possible mechanism for the observed decease in total protein and lysozyme would be that the vasoconstrictor effects of oxym etazoline also apply to the vessels supplying nasal submucosal glands and that this decrease in blood supply is reflected by a decrease in s ecretion.