title: Effects of estradiol on proliferation and metabolism of rabbit mandibular condylar cartilage cells in vitro.
abstract: OBJECTIVE
  To investigate the effects in vitro of 17 beta-estradiol (E2) on the proliferation and metabolism of rabbit mandibular condylar cartilage cells.
  
  
  METHODS
  Chondrocytes were derived from neonatal rabbit mandibular condylar cartilage using a modified enzyme method. 17 beta-estradiol was added to the culture medium in a variety of concentrations. Cell growth and DNA, collagen, and proteoglycan synthesis were used as indicators of proliferation and differentiation of condylar chondrocytes. These were measured by cell number, 3H-proline and 35S-incorporation, respectively.
  
  
  RESULTS
  E2 increased cell number and 3H-thymidine incorporation at 10(-8) to 10(-10) mol/L, and 10(-8) to 10(-11) mol/L in a dose-dependent manner, peaking at 10(-8) mol/L and 10(-9) mol/L, respectively. However, further increase in the concentration of estradiol caused inhibition of both cell number and 3H-thymidine incorporation, and this was significant at 10(-6) mol/L. The effect of E2 on proteoglycan synthesis was similar; the maximum stimulating effect was at 10(-8) mol/L, and inhibition was significant at 10(-6) mol/L. There was no obvious stimulatory effect of E2 on 3H-thymidine incorporation observed.
  
  
  CONCLUSIONS
  Estradiol affects condylar chondrocyte cell growth, DNA, and proteoglycan synthesis in a biphasic manner depending on its concentration. This indicates that estrogen may be important in the proliferation and differentiation of mandibular condylar chondrocytes, and could be relevant to some aspects of certain temporomandibular joint diseases by modulating the function of the chondrocytes.
authors.affiliation: Center for Temporomandibular Disorders, Peking University School of Stomatology, Beijing 100081, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Cheng
authors.forename: Xuchen
authors.initials: X
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Xue
authors.forename: Shenglin
authors.initials: S
authors.lastname: Li
authors.forename: Zuyan
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism*; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology*; D008335:Mandibular Condyle / Q000166:cytology* / Q000378:metabolism*; D011817:Rabbits
chemical_list: D004958:Estradiol