title: Effect of estrogen and dietary loading on condylar cartilage.
abstract: OBJECTIVE
  To study the effect of estrogen deficiency and altered temporomandibular joint loading on the histomorphology of condylar cartilage and on the expression of types II and X collagen and matrix metalloproteinase-3 (MMP-3).
  
  
  METHODS
  Thirty-six female rats were divided into four groups: ovariectomized rats on a normal diet, nonovariectomized control rats on a normal diet, ovariectomized rats on a soft diet, and nonovariectomized control rats on a soft diet. Ovariectomy was performed at the age of 60 days. Repeated-measures ANOVA was used to analyze the data.
  
  
  RESULTS
  The condylar cartilage in the ovariectomized normal diet group showed a significantly higher number of cells than in the nonovariectomized control rats (P < .001). The proportional amount of MMP-3 expression was significantly higher in the ovariectomized rats than in the nonovariectomized control rats in both diet groups (P < .001). The area covered by types II and X collagen was significantly higher in the experimental groups than in the control groups (P < .01).
  
  
  CONCLUSIONS
  Condylar cartilage is sensitive to both estrogen level and dietary loading.
authors.affiliation: Department of Prosthetic Dentistry and Stomatognatic Physiology.
authors.forename: Marko
authors.initials: M
authors.lastname: Orajärvi
authors.forename: Elina
authors.initials: E
authors.lastname: Puijola
authors.forename: Shi-Bin
authors.initials: SB
authors.lastname: Yu
authors.forename: Xiaodong
authors.initials: X
authors.lastname: Liu
authors.forename: Petri
authors.initials: P
authors.lastname: Tiilikainen
authors.forename: Meiqing
authors.initials: M
authors.lastname: Wang
authors.forename: Aune
authors.initials: A
authors.lastname: Raustia
authors.forename: Pertti
authors.initials: P
authors.lastname: Pirttiniemi
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology*; D019902:Chondrocytes / Q000378:metabolism; D024043:Collagen Type II / Q000096:biosynthesis*; D024121:Collagen Type X / Q000096:biosynthesis*; D003799:Dental Stress Analysis; D004032:Diet; D004967:Estrogens / Q000172:deficiency*; D005260:Female; D008335:Mandibular Condyle / Q000503:physiopathology*; D008409:Mastication / Q000502:physiology; D019278:Matrix Metalloproteinase 3 / Q000096:biosynthesis*; D010052:Ovariectomy; D051381:Rats; D013704:Temporomandibular Joint / Q000502:physiology*
chemical_list: D024043:Collagen Type II; D024121:Collagen Type X; D004967:Estrogens; D019278:Matrix Metalloproteinase 3