title: [Effect of experimentally created occlusal disorders on the expression of estrogen in rat condylar cartilage].
abstract: OBJECTIVE
  To investigate the effect of experimentally created occlusal disorders (ECOD) on the expression of estrogen in rat condylar cartilage.
  
  
  METHODS
  The model of ECOD was created by moving right upper and left lower first molars anteriorly. The animals in ECOD were sacrificed at 2, 4, 6, 8 weeks later. In removed occlusal disorders group, the moved first molars were extracted at 6 weeks later, and the animals were sacrificed 2 weeks later. The expression of estrogen was detected by SABC technique of immunocytochemistry, and then was analyzed by the density of estrogen-positive chondrocytes.
  
  
  RESULTS
  1) Estrogen was abundant in mature layer and hypertrophic layer of rat mandibular condylar cartilage. 2) In control group, the expression of estrogen decreased gradually from 6-week-old to 16-week-old. 3) In both childhood and puberty rats, the expression of estrogen in experiment group was significantly higher at 2 weeks after treatment, while no difference was found at 4, 6, 8 weeks after treatment. However, the expression in removed occlusal disorder group was higher than that in control group and 8 weeks of ECOD group.
  
  
  CONCLUSIONS
  In rat condylar cartilage, the expression of estrogen de-creases with age. Induced by ECOD, the expression of estrogen increases in early stage of remodelling activity.
authors.affiliation: Dept. of Prosthodontics, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Bei
authors.initials: B
authors.lastname: Li
authors.forename: Shi-bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Qi-hong
authors.initials: QH
authors.lastname: Li
authors.forename: Jun
authors.initials: J
authors.lastname: Wen
authors.forename: Zhi-wei
authors.initials: ZW
authors.lastname: Dong
authors.forename: Mei-qing
authors.initials: MQ
authors.lastname: Wang
mesh_terms: D000818:Animals; D002358:Cartilage, Articular; D019902:Chondrocytes; D004967:Estrogens; D007150:Immunohistochemistry; D008335:Mandibular Condyle; D008963:Molar; D051381:Rats; D012741:Sexual Maturation
chemical_list: D004967:Estrogens