FATTORI B.

GIAMBELLUCA M.A.

GIANNESSI F

RUFFOLI R.

English

RUFFOLI, RICCARDO

GIAMBELLUCA, MARIA

FATTORI, BRUNO

GIANNESSI, FRANCESCO

Archivio della Ricerca - Università di Pisa

ULTRASTRUCTURAL STUDY OF THE NADPH-DIAPHORASE ACTIVITYIN THE HUMAN NASAL RESPIRATORY MUCOSAIN VASOMOTOR RHINITISR. RUFFOLI1. M.A. GIAMBELLUCA1, B. FATTORI2, F. GIANNESS11'Dip. di Morfologia Umana e Biologia Applicata; 2Dip. di Neuroscienze, Unita di ORL- Facolta di Medicina e Chirurgia dell'Universita degli Studi di PisaINTRODUCTION. In normal subjects the nasal respiratory mucosa (NRM) is coveredby a pseudostratified columnar epithelium. Ciliated cells (CC), goblet cells (GC)and basal cells (BC) are the cells occurring with greatest frequency. Recently nitricoxide synthase (NOS) has been detected in nasal respiratory epithelium (NRE) (1).In normal subjects, the epithelial NO increases the ciliary beat frequency and mayact as vasodilator. In addition, it is involved in host defence by its cytotoxic effects.The role of the epithelial NO in the respiratory pathology is still unclear. Recent lightmicroscopy studies have shown an increased NOS activity in the bronchial epitheli-um from subjects with asthma (2) and in the NRE from patients with chronic rhinitis(1). Vasomotor rhinitis (VMR) is a nonallergic, noninfectious chronic type of rhinitiswith nasal congestion and rhinorrea, but without nasal eosinophilia. In this researchwe investigated the ultrastructural distribution of NOS in the NRE from normal sub-jects and from patients affected by VMR. NADPH-diaphorase (NADPH-d) histo-chemistry was employed. It has been in fact shown that staining for NADPH-d activ-ity overlaps in the NRE with the immunolocalization of NOS (1, 3).MATERIAL AND METHODS. Samples of NRM were obtained from 4 normal sub-jects during corrective surgery of the nasal septum, and from 7 patients with VRM un-dergone to surgical reduction of the inferior turbinates. The specimens, fixed with alde-hydes and processed for NADPH-d ultracytochemistry (4), were post-fixed in osmi-um tetroxide and embedded in Epon 812, following the usual procedures.RESULTS AND DISCUSSION. In the normal NRE a weak enzymatic reaction wasfound in the sovranuclear region of the CC. The reaction was generally absent in theBC and in the GC. In patients with VMR the NRE appeared strongly alterated. Theloss of CC and GC was the most evident ultrastructural finding. The BC did not showjunctional specializations and were separated by large irregular spaces. Several dis-continuities were found in the basement membrane. A strong NADPH-d activity, dis-tributed in the nuclear envelope, in the mithocondria and in the cisternae of SER, wasrecognized in the BC. The hypothesis is put forward that the epitelial alterations ob-served in the VMR could be, at least in part, the consequence of the strong NO pro-duction in the BC, causing cytotoxic effects on the CC and BC and blocking the re-generative epithelial processes.REFERENCES. 1) Furukawa K. et al. Am J Respir Crit Care Med 153, 847-850, 1996;2) Hamid Q. et al. Lancet 342, 1510-1513, 1993; 3) Lee S.H. et al. Acta Oto-Laryn-gol 115, 823-829, 1995; 4) Wolf G. et al. Neurosci Lett 147, 63-66, 1992.185

Ultrastructural study of the NADPH-diaphorase activity in the human nasal respiratory mucosa in vasomotor rhinitis

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Ultrastructural study of the NADPH-diaphorase activity in the human nasal respiratory mucosa in vasomotor rhinitis

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