title: [Morphological study of thick basement membrane-like layer in chronic rhinosinusitis].
abstract: OBJECTIVE
  To observe the thick basement membrane-like layer under the damaged epithelium in patients with chronic rhinosinusitis (CRS) and to study its principal components.
  
  
  METHODS
  Patients (n = 40) with CRS undergoing functional endoscopic sinus surgery were recruited for the study. Patients (n = 10) with no evidence of sinus disease were used as control subjects. Ethmoidal sinus mucosa specimen were stained by PAS staining to measure the thickness of basement membrane-like layer. Immunohistochemical staining, picrosirius-polarization method and transmission electron microscopy (TEM) were used to analyse the nature of the layer.
  
  
  RESULTS
  The thickness of basement membrane-like layer in CRS type I and CRS type II were significantly increased compared with normal control subjects (t = 5. 426, P < 0. 01; t = 8. 375, P < 0.01). The thickness of CRS type II was significantly greater compared with CRS type I (t = 3. 908, P < 0.01). There was no difference between atopic group and inotropic group (t = 0.803, P> 0.05). There was no expression of fibronectin, laminin, IgA, IgG and IgM in the thick basement membrane-like layer. A thick reticular structure containing collagen fibrils and devoid of cellular elements was observed by TEM.
  
  
  CONCLUSIONS
  This study demonstrates that a long-standing chronic inflammation leads to deposition of collagens type I , III and IV under the damaged epithelium, resulting in an increasingly thick sub-basement membrane layer.
authors.affiliation: Department of Pathology, Beijing Tongren Hospital Affiliated of Capital University of Medical Sciences, Beijing 100730, China.
authors.forename: Le
authors.initials: L
authors.lastname: Liang
authors.forename: Hong-gang
authors.initials: HG
authors.lastname: Liu
authors.forename: Chun-yan
authors.initials: CY
authors.lastname: He
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001485:Basement Membrane / Q000378:metabolism* / Q000473:pathology*; D016022:Case-Control Studies; D002908:Chronic Disease; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism / Q000473:pathology; D012852:Sinusitis / Q000378:metabolism* / Q000473:pathology*; D055815:Young Adult
chemical_list: D003094:Collagen