Expression of Glucocorticoid Receptors and Cyclooxygenase-2 in Nasal Polyps from Nonallergic Patients

Abstract

Glucocorticoid treatment has been widely used to suppress inflammatory and immune responses. However, from a clinical point of view, its efficacy in the treatment of nasal polyposis seems to vary individually from patient to patient. In the present study, we examined the presence of glucocorticoid receptors (GRs) and cyclooxygenase-2 (COX-2) in the nasal polyps of nonallergic patients as compared with normal controls. Reverse transcription-polymerase chain reaction analyses revealed the presence of both GR messenger RNA and COX-2 messenger RNA expression in nasal polyps from nonallergic patients, as well as in normal nasal mucosa from controls. Consistent with this finding, immunohistochemical analysis demonstrated that GRs and COX-2 were labeled in both tissues. In nasal polyps, GR labeling was associated with the cytoplasm and nucleus of surface mucosa, submucosal glands, endothelial cells, and inflammatory cells. Importantly, COX-2 labeling was seen in the cytoplasm of surface mucosa, submucosal glands, and the vascular wall in nasal polyps. In contrast, in normal nasal tissues, COX-2 labeling was only found in the vascular wall, and the expression was weaker — a finding demonstrating that COX-2 is upregulated in nasal polyps. Therefore, 1) the presence of GRs and COX-2 in nasal polyps from nonallergic patients, as well as upregulation of COX-2 expression, suggests that inflammation may play an important role in the pathophysiology of nasal polyps; and 2) glucocorticoid could be a potential treatment method for suppressing inflammatory processes.