Initial apical migration of junctional epithelium in rats following application of lipopolysaccharide and proteases.
BACKGROUND
Apical migration of junctional epithelium (JE) occurs in association with periodontal pocket formation. The aim of this study was to investigate the gingival changes occurring during apical migration of the JE following application of factors associated with inflammatory periodontal disease pathogenesis.


METHODS
Six-week-old male Wistar rats were divided into six groups: three experimental groups to investigate gingival changes following 2, 4, and 8 weeks topical application of lipopolysaccharide (LPS) and proteases and three control groups using pyrogen-free water. After 2, 4 or 8 weeks, nuclear DNA fragmentation was detected in periodontal ligament (PDL) fibroblasts using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) method, and proliferative activities of the basal cells and fibroblasts were evaluated through expression of proliferating cell nuclear antigen (PCNA). Collagen destruction was examined histologically.


RESULTS
Gingiva treated with LPS and proteases showed an increase in PCNA-positive basal cells but not the fibroblasts. Collagen destruction was observed at 2 weeks; apical migration of the JE and TUNEL-positive fibroblasts was seen at 4 weeks.


CONCLUSIONS
Following application of LPS and proteases to rat gingival sulci, the apical migration of the JE appears to occur simultaneously with the apoptosis of PDL fibroblasts, which in turn follows proliferation of the basal cells and collagen destruction.
Ekuni
Daisuke
D
Department of Oral Health, Okayama University Graduate School of Medicine and Dentistry, Okayama, Japan.
Tomofuji
Takaaki
T
Yamanaka
Reiko
R
Tachibana
Kentaro
K
Yamamoto
Tatsuo
T
Watanabe
Tatsuo
T
D000818:Animals; D049109:Cell Proliferation; D004846:Epithelial Attachment / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D005889:Gingival Recession / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology; D020287:In Situ Nick-End Labeling / Q000379:methods; D008070:Lipopolysaccharides / Q000009:adverse effects*; D008297:Male; D010447:Peptide Hydrolases / Q000009:adverse effects*; D010513:Periodontal Ligament / Q000187:drug effects / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018709:Statistics, Nonparametric
D008070:Lipopolysaccharides; D018809:Proliferating Cell Nuclear Antigen; D010447:Peptide Hydrolases