title: Matrix metalloproteinases 2 and 9 are concentrated in the luminal aspect of the cricoid cartilage, diminish with loss of perichondrium, and are reinstated by transforming growth factor beta 3.
abstract: OBJECTIVE
  We determined the location of matrix metalloproteinases (MMP) 2 and 9, and whether the luminal perichondrium or transforming growth factor (TGF) beta3 influences the presence of MMP-2 and/or -9 within the chondrocytes of the cricoid cartilage.
  
  
  METHODS
  Subglottises from 15 neonatal mice were divided into group A (N = 5; luminal epithelium intact, grown in basic medium), group B (N = 5; epithelium-free, with sections of luminal perichondrium removed, grown in basic medium), and group C (N = 5; epithelium-free, with sections of luminal perichondrium removed, grown in basic medium with supplemental TGF-beta3). Immunohistochemical analysis was done to identify MMP-2 and -9 distributions.
  
  
  RESULTS
  Group A demonstrated concentrations of MMP-2 and -9 in the luminal perichondrial and adjacent chondrocytes with a gradual decrease in signal intensity toward the outer perichondrium. Group B showed findings similar to those in group A, but in the region of removed perichondrium, the adjacent chondrocytes lost MMP-2 and -9 signal. The group C rings demonstrated reestablishment of MMP-2 and -9 signal in regions of luminal perichondrial loss.
  
  
  CONCLUSIONS
  Localization of MMP-2 and -9 is predominantly in the luminal perichondrium and gradually decreases toward the outer perichondrium. The luminal perichondrium maintains expression of MMP-2 and -9 within the adjacent chondrocytes. Exogenous TGF-beta3 reestablishes production of at least MMP-9, and probably MMP-2, in cricoid cartilages missing luminal perichondrium.
authors.affiliation: Department of Otolaryngology, Massachusetts Eye and Ear Infirmary and Harvard Medical School, Boston, Massachusetts, USA.
authors.forename: Efrain A
authors.initials: EA
authors.lastname: Martinez-Alvernia
authors.forename: Leila A
authors.initials: LA
authors.lastname: Mankarious
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D019902:Chondrocytes / Q000187:drug effects / Q000378:metabolism; D003238:Connective Tissue / Q000378:metabolism* / Q000601:surgery; D003413:Cricoid Cartilage / Q000166:cytology / Q000378:metabolism* / Q000601:surgery; D007150:Immunohistochemistry; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D053782:Transforming Growth Factor beta3 / Q000494:pharmacology*
chemical_list: D053782:Transforming Growth Factor beta3; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9