title: [Effect of gradually induced disordered occlusion on the expression of osteoprotegerin and receptor activator of nuclear factor-kappaB ligand in mandibular condylar cartilage of rats].
abstract: OBJECTIVE
  To investigate the effect of gradually induced disordered occlusion (GIDO) on the expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) in mandibular condylar cartilage of rats.
  
  
  METHODS
  Totally 48 rats, aged 8 weeks were included, and were divided into experimental and control groups randomly at 4 time points, with same gender distribution (n=3). By inserting elastic rubber band the right side mandibular first molar and the left side maxillary first molar were moved mesially. Four weeks later, the right side mandibular third molar and the left side maxillary third molar were moved distally with same method. In this way, the GIDO was established in rats. The rats were sacrificed at the end of 2th, 4th, 6th and 8th week respectively after the application of the GIDO. The expression of OPG and RANKL in condylar cartilage was examined with immunohistochemical method and calculated by the area of positive cell percentage.
  
  
  RESULTS
  OPG and RANKL expressed predominantly in condylar cartilage hypertrophic layer. The rats in experimental group expressed a higher OPG level in all of the 4 time points than their age-matched controls (P<0.05), while RANKL were higher in 2, 6, 8 weeks subgroups (P<0.05), but not in 4 weeks subgroup. No differences were found between male and female subgroups.
  
  
  CONCLUSIONS
  The present results suggest that both OPG and RANKL take part in the condylar cartilage remodeling procedure in the present rat model.
authors.affiliation: Dept. of Oral Anatomy and Physiology, School of Stomatology, The Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Lifeng
authors.initials: L
authors.lastname: Xiong
authors.forename: Lei
authors.initials: L
authors.lastname: Sun
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: He
authors.forename: Meiqing
authors.initials: M
authors.lastname: Wang
mesh_terms: D000818:Animals; D002356:Cartilage; D005260:Female; D006801:Humans; D008297:Male; D008335:Mandibular Condyle; D008963:Molar; D053244:Osteoprotegerin; D053245:RANK Ligand; D051381:Rats
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand