Possible involvement of nitric oxide and peroxynitrite in nasal polyposis.
BACKGROUND
Nitric oxide (NO) is implicated in inflammation. Its role in the pathogenesis of nasal polyposis is not clear.


METHODS
The expression of inducible NO synthase (iNOS), and the production of peroxynitrite represented by the formation of 3-nitrotyrosine (3-NT) were examined by immunohistochemistry in nasal polyps. The contents of superoxide dismutases (SODs) in nasal polyps and nasal mucosa were assessed by Western blot analyses.


RESULTS
iNOS expression and 3-NT accumulation were noted in mucosal epithelium, vascular endothelium, and interstitial cells of nasal polyps. In comparison with our previous study on the nasal mucosa from patients with rhinitis, the stromal cells of the nasal polyp had higher labeling intensity for both iNOS and 3-NT. The polyp showed similar levels of CuZnSOD and MnSOD as those of nasal mucosa.


CONCLUSIONS
The iNOS/NO system may be important in the pathophysiology of nasal polyposis. The increased peroxynitrite may result from increased iNOS expression but is not related to decreased SODs.
Kang
Bor-Hwang
BH
Department of Otolaryngology--Head and Neck Surgery, Tri-Service General Hospital, Taipei, Taiwan, Republic of China.
Huang
Nan-Chieh
NC
Wang
Hsing-Won
HW
D000328:Adult; D000368:Aged; D015153:Blotting, Western; D004804:Eosinophils / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism / Q000473:pathology; D009298:Nasal Polyps / Q000378:metabolism* / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D030421:Peroxynitrous Acid / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000378:metabolism
D030421:Peroxynitrous Acid; D009569:Nitric Oxide; C002744:3-nitrotyrosine; D014443:Tyrosine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D013482:Superoxide Dismutase