Ultrastructural and ultracytochemical study of the human nasal respiratory epithelium in vasomotor rhinitis.
OBJECTIVE
Several pieces of evidence have suggested that nitric oxide (NO) fulfills important functions in the respiratory mucosa, under both normal and pathological conditions. This study was performed to investigate the role of NO in the nasal respiratory epithelium of patients affected by vasomotor rhinitis. The structure and ultrastructure of the epithelium were also examined.


METHODS
The localization of NO synthase activity was determined by means of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase ultracytochemistry. Nasal mucosa was obtained from patients who had undergone surgical therapy for reduction of the inferior turbinate.


RESULTS
Examination of hematoxylin-eosin-stained sections revealed that most of the nasal mucosa covering the surgical samples was characterized by severe epithelial damage. The ultrastructural study confirmed the light microscopic observations. Ciliary loss, absence of the intercellular junctions and distension of the intercellular spaces were found in the damaged epithelium. The basement membrane was frequently interrupted. Some epithelial cells were identified as basal cells. Other cells of the damaged epithelium were probably involuted ciliated and goblet cells. The ultracytochemical study showed that the basal cells were NADPH-diaphorase-negative in healthy subjects and strongly NADPH-diaphorase-positive in subjects with vasomotor rhinitis.


CONCLUSIONS
It is suggested that NO has cytotoxic effects and causes inhibition of mitotic activity in the basal cells, leading to epithelial disruption and breakdown of the protective functions of the epithelium.
Giannessi
Francesco
F
Dipartimento di Morfologia Umana e Biologia Applicata, Facoltà di Medicina e Chirurgia, Università di Pisa, Pisa, Italy.
Fattori
Bruno
B
Ursino
Francesco
F
Giambelluca
M Anita
MA
Soldani
Paola
P
Scavuzzo
Maria C
MC
Ruffoli
Riccardo
R
D000328:Adult; D001485:Basement Membrane / Q000378:metabolism* / Q000648:ultrastructure; D002923:Cilia / Q000648:ultrastructure; D005260:Female; D006801:Humans; D008297:Male; D009297:Nasal Mucosa / Q000201:enzymology* / Q000648:ultrastructure*; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D012223:Rhinitis, Vasomotor / Q000201:enzymology* / Q000473:pathology* / Q000601:surgery; D014420:Turbinates / Q000378:metabolism / Q000473:pathology / Q000601:surgery
D019001:Nitric Oxide Synthase