Effects of estrogen on the condylar cartilage of the rat mandible in organculture

Purpose: The effects of estrogen on bone have been well documented. However , very little is known about the regulatory role of estrogen on cartilage a nd, in particular, the secondary cartilage of the mandibular condyle. The a ims 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 v arying 17 beta-estradiol (E-2) concentrations on the proteoglycan content o f this tissue. Materials and Methods: Mandibular condyles of 16 female Sprague-Dawley rats were resected. Eighteen of these condyles were divided into three groups a nd the condylar cartilage was removed and placed in organ culture for 4 day s 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 prote oglycan content along with six specimens not passed through the organ cultu re. Six intact mandibular condyles also were resected and placed in organ c ulture with the same varying E-2 concentrations, and the condylar cartilage was analyzed for estrogen receptors along with two condyles not passed thr ough the culture system. Results: Estrogen receptors were evenly distributed within the chondroblast ic and hypertrophic zones in the control group and the group with 10(-11) m ol/L E-2. With E-2 concentrations of 10(-8) mol/L and 10(-6) mol/L, there w as a qualitative decrease in hypertrophic chondroblasts, thickness of the c ondylar cartilage, and a significant decrease in proteoglycan content. Conclusions: This study shows the presence of estrogen receptors in the sec ondary cartilage of the rat mandibular condyle. Estrogen has the potential to cause a decrease in extracellular matrix and thickness of this cartilage .