title: Degradation of noncollagenous components by neutrophil elastase reduces the mechanical strength of rat periodontal ligament.
abstract: OBJECTIVE
  We have previously shown that increases in neutrophil elastase in periodontal ligament with chronic periodontitis results in degradation of the noncollagenous components. The purpose of this study was to investigate whether the destruction of noncollagenous components by treatment with elastase in vitro causes changes in the mechanical properties of the periodontal ligament.
  
  
  METHODS
  The transverse sections of mandibular first molars, prepared from male Wistar rats at 6 wk of age, were digested with 0-50 microg/mL of neutrophil elastase at 37 degrees C for 4 h. Then, their mechanical properties and morphological features were examined.
  
  
  RESULTS
  Digestion with elastase dose-dependently decreased the maximum shear stress and failure strain energy density of the periodontal ligament (p < 0.05-0.01). The histological observations after digestion revealed marked degradation of oxytalan fibers, but no marked changes of the collagen fibers, which was confirmed by the detection of very low quantities of hydroxyproline in the digest. The light and scanning electron micrographs showed that the elastase degraded the interfibrillar substances in the periodontal ligament and exposed individual collagen fibrils.
  
  
  CONCLUSIONS
  These results suggest that the increased neutrophil elastase observed in periodontal disease degrades the oxytalan fibers and interfibrillar substances in the periodontal ligament to decrease its mechanical strength.
authors.affiliation: Department of Biochemistry, Tsurumi University School of Dental Medicine, Yokohama, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ujiie
authors.forename: A
authors.initials: A
authors.lastname: Shimada
authors.forename: K
authors.initials: K
authors.lastname: Komatsu
authors.forename: K
authors.initials: K
authors.lastname: Gomi
authors.forename: S
authors.initials: S
authors.lastname: Oida
authors.forename: T
authors.initials: T
authors.lastname: Arai
authors.forename: M
authors.initials: M
authors.lastname: Fukae
mesh_terms: D000818:Animals; D006801:Humans; D019272:Leukocyte Elastase / Q000008:administration & dosage / Q000378:metabolism*; D008297:Male; D008963:Molar / Q000000981:diagnostic imaging / Q000201:enzymology*; D010513:Periodontal Ligament / Q000737:chemistry / Q000201:enzymology* / Q000648:ultrastructure; D011859:Radiography; D051381:Rats; D017208:Rats, Wistar; D033081:Shear Strength
chemical_list: D019272:Leukocyte Elastase