Expression Of Nitric Oxide Synthase And Its Significance In Nasal Polyps

Recent evidence has documented that nitric oxide ,an endogenous souble gas molecule,is a new intercellular messenger and effector involved with various aspects of human physiology. Nitric oxide(NO) is produced when L-arginine is transformed into L-citrulline by NOS. Three different isotypes of NOS has been identified in human cells. Types I and II NOS are named neuronal NOS(nNOS) and inducible NOS(iNOS), respectively, and type III NOS is named endothelial NOS(eNOS).NO plays an important role in the regulation of vascular tone, host defence, inflammation, coagulation and neurotransmission when NO is produced at low concentration, but it has dural effects, it performs a wide range of pathologic functions at high concentration. Attention has focused on the importance of NO in the formation of nasal polyps,only several studies have reported the association between iNOS and nasal polyps. The aim of the present study was to identify the expression of three types NOS and discuss the significance of NOS in the nasal polyps and nasal mucosa. Septectomy and immunohistochemisty were used to examine NOS activity and identify its expression in human nasal specimens from patients undergoing nasal spectrumtomy(n=20) or nasal polypectomy(n=30). The resuls as follow:l.The activity of NOS was significantly higher in nasal polyps than in nasal mucosa(P<0.01).2.eNOS reaction product was located in epithelial cells and vascular endothelial cells and nasal glands of nasal mucosa.iNOS reaction product was founded in several cells.Amount of eNOS positive cells was significantly higher than of iNOS positive cells in nasal mucosa (P<0.01 ).nNOS reaction product was not founded.3.iNOS reaction product was located in epithelial cells and vascular endothelial cells and nasal glands and inflammation cells of nasal polyps. eNOS reaction product was located in epithelial cells and vascular endothelial cells and nasal glands of nasal polyps. nNOS reaction product was not founded. Amount of iNOS positive cells in nasal polyps was significantly higher than in nasal mucosa(P<0.01). Amount of iNOS positive cells was significantly higher than of eNOS positive cells in nasal polyps(P<0.01).There was no quantitative difference of eNOS between in nasal polyps and nasal mucosa.From the results of this study ,NOS activity is significantly higher in nasal polyps than in nasal mucos. eNOS, mainly expressed in nasal mucosa, which pruduces NO at low concentration that plays an important role in nasal mucosa physiology. iNOS, mainly expressed in nasal polyps, which pruduces NO at high concentration that plays an important role in the formation of nasal polyps. The present study plays an important role in study the mechanism of nasal polyps.