Neutrophil elastase is involved in the initial destruction of human periodontal ligament.
OBJECTIVE
It has been reported that noncollagenous proteins may provide mechanical strength to the periodontal ligament. Several proteolytic activities, including that of neutrophil elastase, are reported to increase significantly in periodontal disease. The aim of this study was to investigate the function of neutrophil elastase in the initial destruction of periodontal ligament at early stages of periodontal disease.


METHODS
The detection and identification of proteinases in chronic periodontitis and healthy periodontal ligament were examined by zymographic and zymo-Western analysis. The morphological changes of periodontal ligament, digested with or without authentic proteinases, were observed using scanning electron microscopy.


RESULTS
Increases in neutrophil elastase, plasminogen, and matrix metalloproteinase-9 were detected in periodontal ligament from chronic periodontitis, compared with healthy periodontal ligament. Among these proteinases, only neutrophil elastase digested the intact noncollagenous proteins of periodontium. When human healthy periodontal ligament was directly digested by neutrophil elastase in an in vitro system, the morphological features were quite similar to that of the periodontal ligament in chronic periodontitis . In healthy periodontal ligament, the collagen fibrils are covered with noncollagenous proteins containing 110 kDa acidic glycoprotein, which was degraded initially by the neutrophil elastase.


CONCLUSIONS
It was concluded that neutrophil elastase is involved in the degradation of noncollagenous protein-covered collagen fibrils in the early destructive stages of periodontal disease.
Ujiie
Y
Y
Department of Biochemistry, Tsurumi University, School of Dental Medicine, Yokohama, Japan.
Oida
S
S
Gomi
K
K
Arai
T
T
Fukae
M
M
D000328:Adult; D016022:Case-Control Studies; D002908:Chronic Disease; D005260:Female; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D019272:Leukocyte Elastase / Q000032:analysis / Q000378:metabolism*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis; D009687:Nuclear Proteins; D010513:Periodontal Ligament / Q000201:enzymology* / Q000648:ultrastructure; D010518:Periodontitis / Q000201:enzymology*; D010958:Plasminogen / Q000032:analysis; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface
C087425:ANP32A protein, human; D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D016601:RNA-Binding Proteins; D011956:Receptors, Cell Surface; C065686:carcinoembryonic antigen binding protein, human; D010958:Plasminogen; D019272:Leukocyte Elastase; D020780:Matrix Metalloproteinase 9