Effects of estrogen on the condylar cartilage of the rat mandible in organ culture.
OBJECTIVE
The effects of estrogen on bone have been well documented. However, very little is known about the regulatory role of estrogen on cartilage and, in particular, the secondary cartilage of the mandibular condyle. The aims of this study were to determine whether estrogen receptors are present in the condylar cartilage of the rat mandible and to assess the effect of varying 17beta-estradiol (E2) concentrations on the proteoglycan content of this tissue.


METHODS
Mandibular condyles of 16 female Sprague-Dawley rats were resected. Eighteen of these condyles were divided into three groups and the condylar cartilage was removed and placed in organ culture for 4 days with media containing different concentrations of estrogen: 10(-11) mol/L, 10(-8) mol/L, and 10(-6) mol/L. The cartilage then was analyzed for proteoglycan content along with six specimens not passed through the organ culture. Six intact mandibular condyles also were resected and placed in organ culture with the same varying E2 concentrations, and the condylar cartilage was analyzed for estrogen receptors along with two condyles not passed through the culture system.


RESULTS
Estrogen receptors were evenly distributed within the chondroblastic and hypertrophic zones in the control group and the group with 10(-11) mol/L E2. With E2 concentrations of 10(-8) mol/L and 10(-6) mol/L, there was a qualitative decrease in hypertrophic chondroblasts, thickness of the condylar cartilage, and a significant decrease in proteoglycan content.


CONCLUSIONS
This study shows the presence of estrogen receptors in the secondary cartilage of the rat mandibular condyle. Estrogen has the potential to cause a decrease in extracellular matrix and thickness of this cartilage.
Department of Biomedical Sciences, Baylor College of Dentistry, Dallas, TX 75246, USA.
M C
MC
Ng
R P
RP
Harper
C T
CT
Le
B S
BS
Wong
D000704:Analysis of Variance; D000818:Animals; D002356:Cartilage / Q000737:chemistry / Q000187:drug effects*; D019902:Chondrocytes / Q000737:chemistry / Q000187:drug effects; D004247:DNA / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000187:drug effects; D005260:Female; D006984:Hypertrophy; D007150:Immunohistochemistry; D008335:Mandibular Condyle / Q000737:chemistry / Q000187:drug effects*; D009924:Organ Culture Techniques; D011509:Proteoglycans / Q000032:analysis / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D011960:Receptors, Estrogen / Q000032:analysis / Q000187:drug effects
D011509:Proteoglycans; D011960:Receptors, Estrogen; D004958:Estradiol; D004247:DNA