Levels of intracellular protein and messenger RNA of mucin and lysozyme in normal human nasal and polyp epithelium.

Mucus hypersecretion is a characteristic feature in chronic sinusitis with nasal polyps. The objective of this study is to examine whether the polyp epithelium itself contributes to a certain extent to the increased mucous secretions in chronic sinusitis with nasal polyps, and if it does, to determine which mucin genes are responsible for the increased mucin secretion. Three pooled samples of normal nasal epithelial cells from each subject were obtained by scrapings from the inferior turbinates of 30 healthy adult volunteers and nasal polyps from 6 patients who underwent intranasal ethmoidectomy and polypectomy. Isolated epithelial cells were used for total RNA isolation for reverse transcriptase polymerase chain reaction and cell lysates for immunoblotting. The intracellular level of mucin from polyp epithelium was 2.9 times higher than that of normal nasal epithelium (P < .05). Interestingly, MUC2 and MUC8 messenger RNA (mRNA) levels were clearly upregulated in polyp epithelium compared with those of normal turbinate epithelium. Polyp epithelium can be considered to contribute in part to increased secretion in chronic sinusitis with polyps, and increased mucous secretion might be related to the increased mRNA level of MUC2 or MUC8 or both.