title: Occlusal effects on longitudinal bone alterations of the temporomandibular joint.
abstract: The pathological changes of subchondral bone during osteoarthritis (OA) development in the temporomandibular joint (TMJ) are poorly understood. In the present study, we investigated the longitudinal alterations of subchondral bone using a rat TMJ-OA model developed in our laboratory. Changes in bone mass were examined by micro-CT, and changes in osteoblast and osteoclast activities were analyzed by real-time PCR, immunohistochemistry, and TRAP staining. Subchondral bone loss was detected from 8 weeks after dental occlusion alteration and reached the maximum at 12 weeks, followed by a repair phase until 32 weeks. Although bone mass increased at late stages, poor mechanical structure and lower bone mineral density (BMD) were found in these rats. The numbers of TRAP-positive cells were increased at 12 weeks, while the numbers of osteocalcin-expressing cells were increased at both 12 and 32 weeks. Levels of mRNA expression of TRAP and cathepsin K were increased at 12 weeks, while levels of ALP and osteocalcin were increased at both 12 and 32 weeks. These findings demonstrated that there is an active bone remodeling in subchondral bone in TMJs in response to alteration in occlusion, although new bone was formed with lower BMD and poor mechanical properties.
authors: Department of Oral Anatomy and Physiology and TMD, School of Stomatology, Fourth Military Medical University, 145 Changlexi Road, Xi'an 710032, China.
authors: J
authors: J
authors: Zhang
authors: K
authors: K
authors: Jiao
authors: M
authors: M
authors: Zhang
authors: T
authors: T
authors: Zhou
authors: X-D
authors: XD
authors: Liu
authors: S-B
authors: SB
authors: Yu
authors: L
authors: L
authors: Lu
authors: L
authors: L
authors: Jing
authors: T
authors: T
authors: Yang
authors: Y
authors: Y
authors: Zhang
authors: D
authors: D
authors: Chen
authors: M-Q
authors: MQ
authors: Wang
mesh_terms: D000818:Animals; D015519:Bone Density; D016723:Bone Remodeling; D056657:Cathepsin K / Q000096:biosynthesis / Q000235:genetics; D003769:Dental Occlusion, Traumatic / Q000150:complications*; D003799:Dental Stress Analysis; D004195:Disease Models, Animal; D005260:Female; D008335:Mandibular Condyle / Q000000981:diagnostic imaging / Q000473:pathology*; D010003:Osteoarthritis / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D010006:Osteoblasts / Q000378:metabolism; D015675:Osteocalcin / Q000096:biosynthesis / Q000235:genetics; D010010:Osteoclasts / Q000378:metabolism; D053244:Osteoprotegerin / Q000096:biosynthesis / Q000235:genetics; D053245:RANK Ligand / Q000096:biosynthesis / Q000235:genetics; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D060888:Real-Time Polymerase Chain Reaction; D013704:Temporomandibular Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D055114:X-Ray Microtomography
chemical_list: D053244:Osteoprotegerin; D053245:RANK Ligand; D015675:Osteocalcin; D056657:Cathepsin K