title: Hyaluronan metabolism in overloaded temporomandibular joint.
abstract: This study aimed to examine hyaluronan (HA) metabolism in relation to the onset and progression of temporomandibular joint osteoarthritis (TMJ-OA) induced by mechanical overloading. Two-month-old and 6-month-old C57BL/6N mice were divided into experimental and untreated control groups (n = 5/group). A sliding plate was attached to the maxillary incisors of the experimental mice for 10 days to overload the condylar cartilage in TMJ. In experimental group, profound cartilage degradation was detected in haematoxylin-eosin, Safranin-O-Fast Green-stained sections. It was also shown that the cartilage degradation was greater in older mice in both the control and the experimental groups. The number of HABP-positive cells was decreased by mechanical overloading and with age. The reduction of HA expression was correlated with the progression of cartilage degradation induced by mechanical overloading. The absolute quantification of the mRNA expression related to HA synthesis and HA degradation was also performed in each group. The mRNA expression levels of HA synthase (HAS) 2 and 3 were lower in the experimental group compared with the control group in the younger mice. In contrast, the mRNA expression levels of the HA degradation gene, HYAL2 and KIAA1199, were higher in the experimental group compared with the control group in the older mice. Thus, mechanical overload differently affected the balance of HA degradation and HA synthesis in the older and younger mice, respectively. In conclusion, mechanical overloading affects HA metabolism and it might initiate or amplify the condylar cartilage degradation.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Shinohara
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Izawa
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Mino-Oka
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Mori
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Iwasa
authors.affiliation: Genetic Disease Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA.
authors.forename: T
authors.initials: T
authors.lastname: Inubushi
authors.affiliation: Genetic Disease Program, Sanford Children's Health Research Center, Sanford-Burnham Medical Research Institute, La Jolla, CA, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Yamaguchi
authors.affiliation: Department of Orthodontics and Dentofacial Orthopedics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan.|Department of Orthodontics, Faculty of Dentistry, King Abdulaziz University, Jeddah, Saudi Arabia.
authors.forename: E
authors.initials: E
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology*; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000378:metabolism*; D008297:Male; D008335:Mandibular Condyle / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D016059:Range of Motion, Articular; D013314:Stress, Mechanical; D013705:Temporomandibular Joint Disorders / Q000378:metabolism* / Q000473:pathology
chemical_list: D006820:Hyaluronic Acid
keywords: hyaluronan; osteoarthritis; temporomandibular joint