Temporomandibular joint (TMJ) diseases predominantly afflict women, suggesting a role of estrogen in the disease etiology. Previously, we determined that decreased occlusal loading (DOL) inhibited collagen type II (Col2) expression in the mandibular condylar cartilage (MCC) of female wild-type (WT) mice whereas no change was observed in males.
Osteoclast Deficiency Contributes to Temporomandibular Joint Ankylosed Bone Mass Formation
Authors
L.H. He, E. Xiao, D.H. Duan, Y.H. Gan, Y. Zhang
Abstract
Ankylosed bone mass in temporomandibular joint ankylosis (TMJA) is an important factor affecting mouth-opening limitation. However, the mechanism underlying the occurrence of ankylosed bone mass remains unknown. Research has shown that osteoblasts and osteoclasts maintain balance in bone remodeling. Thus, we hypothesized that aberrant osteoclastogenesis and osteogenesis may be involved in the occurrence of ankylosed bone mass in TMJA. In this study, we characterized the osteogenesis of bone marrow stem cells and the osteoclastogenesis of myelomonocyte in clinical specimens of TMJA and normal controls. Results showed that, compared with control bone marrow stem cells, TMJA bone marrow stem cells had lower proliferative and osteogenic capacities. The number of osteoclasts in the ankylosed bone mass group dramatically decreased, and myelomonocyte osteoclastogenic potential was impaired. The RANKL/OPG ratio of the ankylosed bone mass group was lower than that of the control group. Thus, our study suggests that osteoclast deficiency may be an important factor affecting bone mass ankylosis.
Estrogen Receptor beta mediates decreased occlusal loading induced inhibition of chondrocyte maturation in female mice
Objective Temporomandibular joint (TMJ) disorders predominantly afflict women, suggesting that estrogen may play a role in the disease process. Defects in mechanical loading-induced TMJ remodeling are believed to be a major etiological factor in TMJ degenerative disease. Previously, we found that, decreased occlusal loading caused a significant decrease in early chondrocyte maturation markers (Sox9 and Col 2) in female, but not male, C57BL/6 wild type mice (1). The goal of this study was to examine the role of Estrogen Receptor (ER) beta in mediating these effects.
Increased mandibular condylar growth in mice with estrogen receptor beta deficiency
A Comparative Analysis of the Articular Cartilage in the Temporomandibular Joint of Gouging and Nongouging New World Monkeys
Both laboratory and field data demonstrate that marmosets gouge trees with wide jaw gapes to elicit exudate flow. Tree gouging distinguishes marmosets from other platyrrhines and presents a natural experiment for studying the morphological consequences of this derived feeding behavior. We utilize comparative histomorphometrics to determine whether loading of the TMJ at wide jaw gapes impacts articular cartilage form in two habitual gouging species