Bilateral anterior elevation prosthesis boosts chondrocytes proliferation in mice mandibular condyle

Abstract

Objective We aimed to develop a mouse model predominating in a proliferative response in the articular cartilage of the temporomandibular joints. Materials and Methods Bilateral anterior elevation of occlusion was developed by installing metal tubes onto the incisors of mice with edge‐to‐edge relation to prevent tooth wear, leading to an increase in the vertical height of the dental occlusion with time. Morphological changes and expression changes in Cyclin D1, Aggrecan, and type II and type X collagen in the mandibular condylar cartilage were detected. In addition, cells were isolated from the mandibular condylar cartilage and exposed to cyclic tensile strain (CTS). Results Compared with age‐matched controls, the tooth length was longer at 3 weeks, 7 weeks, and 11 weeks in BAE mice (p < 0.05), with increased condylar cartilage thickness, matrix amount, and cell number (p < 0.05). Compared with the deep zone cells, CTS stimulated the superficial zone cells to express a higher level of proliferating cell nuclear antigen, Cyclin D1, Aggrecan, and type II collagen but a lower level of type X collagen and alkaline phosphatase. Conclusion Bilateral anterior elevation stimulated the proliferative response in the mandibular condylar cartilage, offering a new therapeutic strategy for cartilage degeneration.

Effects of occlusion modification on the remodelling of degenerative mandibular condylar processes

“…Native incisor wear copes with continuing incisor eruption in rodents have been proposed to be prevented by BAE so that the TMJ cavities become enlarged with time. Bilateral anterior elevation promotes cellular proliferation in the superficial zone cartilage and inhibits cellular differentiation in the deep zone cartilage (Liu et al, ). In the present study, the promoting effect of BAE on cartilage successfully compensated for UAC‐induced cartilage degeneration, as indicated by increases in cell density and the thickness of the cartilage layer, increases in the amount of proteoglycans and Col II and a decrease in the expression of Col X and inflammatory molecules.…”

“…The improvement of occlusion alters the biomechanical environment and thus is helpful in suppressing the degeneration of cartilage (Zhang, Liu, et al, ). Bilateral anterior elevation was recently reported to induce a proliferative response and produce matrix in chondrocytes (Liu et al, ). Hence, explorations on the regeneration capability of TMJ condylar cartilage using the BAE model are expected.…”

“…Then, the tubes were bonded to the mouse maxillary and mandibular incisors with zinc phosphate cement within 5 min. To create a BAE relation of the maxillary and mandibular incisors, the end of the tubes was made flush with the occlusal surface, as we previously reported (Liu et al, ). During the experimental period, the tubes were checked every 2 days to make sure none of the protheses fell off.…”

“…Recently, our group developed a bilateral anterior elevation (BAE) model by installing metal tubes onto the four incisors of the mouse to create edge‐to‐edge occlusion, thus increasing the vertical height of the bite. Bilateral anterior elevation induces proliferative responses and matrix production in chondrocytes in mandibular condylar cartilage (Liu et al, ). Whether BAE is helpful in rescuing the UAC‐induced degradation of cartilage is intriguing.…”

Elder Mice Exhibit More Severe Degeneration and Milder Regeneration in Temporomandibular Joints Subjected to Bilateral Anterior Crossbite

“…For the right-side condyles, serial sections (5 μm thick) in the sagittal plane of condyles were collected using a rotary microtome (RM2135, Leica, Wetzlar, Germany). Hematoxylin-eosin (HE) staining, Safranin-O/fast green staining (SO), and IHC staining for type II collagen (Col-II) (sc-52658, Santa Cruz, CA, United States) and type X collagen (Col-X) (ab58632, Abcam, Cambridge, United Kingdom) were performed as we previously described ( Liu et al, 2019 ). Moreover, immunofluorescence (IF) staining for analysis of the expression of CCP3 (AF7022, Affinity, United States), Ki67 (ab16667, Abcam, Cambridge, United Kingdom), and CD90 (ab225, Abcam, Cambridge, United Kingdom) was performed as we previously reported ( Zhang et al, 2021 ).…”