title: Deterioration of mechanical properties of discs in chronically inflamed TMJ.
abstract: Temporomandibular joint (TMJ) discs frequently undergo degenerative changes in arthritis. However, the biomechanical properties of pathogenic discs remain to be explored. In this study, we evaluated the effects of chronic inflammation on the biomechanical properties of TMJ discs in rats. Chronic inflammation of TMJs was induced by double intra-articular injections of complete Freund's adjuvant for 5 weeks, and biomechanical properties and ultrastructure of the discs were examined by mechanical testing, scanning electron microscopy, and transmission electron microscopy. The instantaneous compressive moduli of the anterior and posterior bands of discs in inflamed TMJs were decreased significantly compared with those in the control group. The instantaneous tensile moduli of the discs of inflamed TMJs also showed significant decreases in both the anterior-posterior and mesial-lateral directions. The relaxation moduli of the discs of inflamed TMJs showed nearly the same tendency as the instantaneous moduli. The surfaces of the discs of inflamed TMJs became rough and porous due to the loss of the superficial gel-like stratum, with many collagen fibers exposed and degradation of the sub-superficial collagen fibrils. Our results suggested that chronic inflammation of TMJ could lead to deterioration of mechanical properties and alteration of disc ultrastructure, which might contribute to TMJ disc displacement.
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: X D
authors.initials: XD
authors.lastname: Wang
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: S J
authors.initials: SJ
authors.lastname: Cui
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: Q
authors.initials: Q
authors.lastname: Luo
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: R J
authors.initials: RJ
authors.lastname: Du
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: X X
authors.initials: XX
authors.lastname: Kou
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration.
authors.forename: J N
authors.initials: JN
authors.lastname: Zhang
authors.affiliation: Department of Orthodontics Center for Craniofacial Stem Cell Research and Regeneration yanhengzhou@gmail.com kqyehuagan@bjmu.edu.cn.
authors.forename: Y H
authors.initials: YH
authors.lastname: Zhou
authors.affiliation: Center for Temporomandibular Disorders and Orofacial Pain, Peking University School and Hospital of Stomatology, 22# Zhongguancun South Avenue, Haidian District, Beijing 100081, China yanhengzhou@gmail.com kqyehuagan@bjmu.edu.cn.
authors.forename: Y H
authors.initials: YH
authors.lastname: Gan
mesh_terms: D000465:Algorithms; D000818:Animals; D001169:Arthritis, Experimental / Q000473:pathology / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D003094:Collagen / Q000648:ultrastructure; D019245:Compressive Strength; D055119:Elastic Modulus; D005260:Female; D024022:Fibrillar Collagens / Q000648:ultrastructure; D005620:Freund's Adjuvant / Q000009:adverse effects; D007270:Injections, Intra-Articular; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D016062:Porosity; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D019224:Temporomandibular Joint Disc / Q000503:physiopathology* / Q000648:ultrastructure; D013705:Temporomandibular Joint Disorders / Q000473:pathology / Q000503:physiopathology*; D013718:Tensile Strength
chemical_list: D024022:Fibrillar Collagens; D003094:Collagen; D005620:Freund's Adjuvant
keywords: arthritis; biomechanics; collagen; disc displacement; temporomandibular disorders; temporomandibular joint