Effects of clarithromycin on cultured human nasal epithelial cells and fibroblasts

Long-term administration of clarithromycin has been reported to be effective in the treatment of chronic sinusitis. To investigate the mechanism underlying the anti-inflammatory activity of clarithromycin, the authors evaluated the effect of clarithromycin on the gene expression of proinflammatory cytokine and the DNA-binding activity of nuclear factor (NF)-kappa B in cultured human nasal epithelial cells and fibroblasts. Cells were incubated with endotoxin purified from nontypable Haemophilus influenzae or interleukin (IL)-1 beta in the presence of clarithromycin.

Northern blot analysis revealed that clarithromycin suppressed IL-1 beta gene expression in human nasal epithelial cells stimulated by H. influenzae endotoxin (HIE). Intercellular adhesion molecule-1 gene expression in nasal fibroblasts stimulated by IL-1 beta was also suppressed by clarithromycin. Furthermore, electrophoretic mobility shift assay demonstrated that clarithromycin reduced DNA-binding activity of NF-kappa B in both human nasal epithelial cells and fibroblasts stimulated by HIE or IL-1 beta, respectively.

The present results suggest that clarithromycin may reduce gene expression of proinflammatory cytokines and adhesion molecules from nasal mucosa at the transcriptional factor level and exert an anti-inflammatory effect on nasal mucosa in chronic sinusitis.