title: [Effect of estrogen-deficiency on expression of osteoprotegerin in alveolar bone: experiment with rats with periodontitis].
abstract: OBJECTIVE
  To investigate the effects of estrogen-deficiency upon the expression of osteoprotegerin (OPG) in alveolar bone so as to clarify the role of estrogen in alveolar bone metabolism.
  
  
  METHODS
  Fifty-three SD rats were randomly divided into 3 groups: OVX group (n=18) undergoing bilateral ovariectomy, OVX + E2 group (n=18), undergoing bilateral ovariectomy and subcutaneous injection of estradiol once 3 days since day 2 after the operation, and sham operation group (n=17) undergoing sham operation. Four weeks after the operation periodontal ligature was conducted and high-sugar diet was fed to establish periodontitis models. Four weeks later the rats were killed. The morphological changes and expression of OPG in alveolar bone were observed by light microscopy and immunohistochemistry.
  
  
  RESULTS
  All the rats showed sparseness of bone trabeculae in alveolar bone and osteoclasts and lacuna at the surface of alveolar bone, especially the rate of the group OVX. The A values (absorption of the OPG expression) in the alveolar bone of the OVX groups was 27 854 +/- 5246, significantly lower than those of the sham operation group and OVX + E2 group (38 799 +/- 6228 and 37 146 +/- 6394 respectively, both P < 0.05) without significant difference between the sham operation group and OVX + E2 group (P > 0.05).
  
  
  CONCLUSIONS
  Estrogen deficiency decreases the expression of OPG in alveolar bone, and enhances the absorption of alveolar bone.
authors.affiliation: Department of Periodontology, Stomatological Hospital, Tianjin Medical University, Tianjin 300070, China. wangyonglan999@tom.com
authors.forename: Yong-lan
authors.initials: YL
authors.lastname: Wang
authors.forename: Li-si
authors.initials: LS
authors.lastname: Fei
authors.forename: Chen-xin
authors.initials: CX
authors.lastname: Jin
authors.forename: Shi-you
authors.initials: SY
authors.lastname: Liu
mesh_terms: D000539:Alveolar Process / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D004967:Estrogens / Q000172:deficiency* / Q000494:pharmacology; D005260:Female; D007150:Immunohistochemistry; D053244:Osteoprotegerin / Q000096:biosynthesis*; D010052:Ovariectomy; D010518:Periodontitis / Q000503:physiopathology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D004967:Estrogens; D053244:Osteoprotegerin