Ng M C, Harper R P, Le C T, Wong B S
Department of Biomedical Sciences, Baylor College of Dentistry, Dallas, TX 75246, USA.
J Oral Maxillofac Surg. 1999 Jul;57(7):818-23. doi: 10.1016/s0278-2391(99)90823-6.
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.
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.
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.
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.
雌激素对骨骼的影响已有充分记载。然而，关于雌激素对软骨，尤其是下颌髁突继发性软骨的调节作用却知之甚少。本研究的目的是确定雌激素受体是否存在于大鼠下颌骨髁突软骨中，并评估不同浓度的17β - 雌二醇（E2）对该组织蛋白聚糖含量的影响。
切除16只雌性Sprague-Dawley大鼠的下颌髁突。其中18个髁突分为三组，将髁突软骨取出并置于器官培养中4天，培养基中含有不同浓度的雌激素：10^(-11) mol/L、10^(-8) mol/L和10^(-6) mol/L。然后分析软骨的蛋白聚糖含量，同时分析6个未经过器官培养的标本。还切除6个完整的下颌髁突并置于含有相同不同E2浓度的器官培养中，分析髁突软骨的雌激素受体，同时分析2个未经过培养系统的髁突。
在对照组和10^(-11) mol/L E2组中，雌激素受体在成软骨细胞和肥大细胞区均匀分布。当E2浓度为10^(-8) mol/L和10^(-6) mol/L时，肥大软骨细胞数量定性减少，髁突软骨厚度变薄，蛋白聚糖含量显著降低。
本研究表明大鼠下颌髁突继发性软骨中存在雌激素受体。雌激素有可能导致该软骨细胞外基质减少和厚度变薄。
