Abstract
The influence of macrolide antibiotics on nitric oxide (NO) generation was examined using human nasal polyp fibroblasts (NPFs) in vitro. Addition of roxithromycin (RXM) at a concentration of ≥ 7.5 μg/ml to cell cultures was shown to suppress NO production in response to stimulation with 25.0 ng/ml tumor necrosis factor (TNF)-α. However, jyosamycin (JM) did not suppress NO production from NPFs induced by TNF-α stimulation in vitro, even when added to cell cultures at a concentration of 20.0 μg/ml. We then examined the influence of RXM on inducible nitric oxide synthase (iNOS) mRNA expression in NPFs. Addition of RXM at a dose of 7.5 μg/ml to cell cultures caused reduction of iNOS mRNA expression, which was enhanced by TNF-α stimulation in vitro.