title: [Effect of sonicated extracts of Porphyromonas gingivalis on receptor activator of NF-κB ligand and osteoprotegerin expression in periodontal ligament cells].
abstract: OBJECTIVE
  To evaluate the effects of sonicated extracts of Porphyromonas gingivalis (Pg) on receptor activator of NF-κB ligand (RANKL) and osteoprotegerin (OPG) expression in human periodontal ligament cells (HPDLC) and the effect of Pg on bone resorption in periodontitis.
  
  
  METHODS
  HPDLC were exposed to 25, 50 mg/L sonicated extracts of Pg for 6 h, HPDLC without treatment served as control. The expression of RANKL-OPG mRNA and protein were examined by real time polymerase chain reaction and Western blotting. OPG protein in the supernatant was examined by enzyme linked immunosorbent assay (ELISA). The data were statistically analyzed by SPSS 13.0 and one-way analysis of variance (ANOVA).
  
  
  RESULTS
  When HPDLC were exposed to sonicated extracts of Pg, the expression of RANKL mRNA and protein in 25 mg/L and 50 mg/L groups were higher than that of control group (P < 0.05), the expression of OPG mRNA in 50 mg/L group (0.087 ± 0.021) was lower than that of control group (0.240 ± 0.019) (P < 0.05), and OPG protein in 25 mg/L and 50 mg/L groups (0.813 ± 0.007, 0.398 ± 0.009) was lower than that of control group (1.131 ± 0.005) (P < 0.01). OPG protein expression in the supernatant was not significantly different between experimental group and control group.
  
  
  CONCLUSIONS
  Sonicated extracts of Pg exposed to HPDLC can up-regulate RANKL expression, down-regulate OPG expression and influence bone metabolism.
authors.affiliation: Department of Periodontics and Mucosa Disease, Capital Medical University School of Stomatology, Beijing 100050, China. zhfengqiu@126.com
authors.forename: Qin
authors.initials: Q
authors.lastname: Feng
authors.forename: Feng-qiu
authors.initials: FQ
authors.lastname: Zhang
authors.forename: Zheng
authors.initials: Z
authors.lastname: Sun
authors.forename: Xin-yan
authors.initials: XY
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
mesh_terms: D000328:Adult; D002478:Cells, Cultured; D006801:Humans; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism*; D010513:Periodontal Ligament / Q000166:cytology / Q000378:metabolism*; D016966:Porphyromonas gingivalis / Q000472:pathogenicity*; D053245:RANK Ligand / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D013010:Sonication; D055815:Young Adult
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human