Unilateral anterior crossbite induces aberrant mineral deposition in degenerative temporomandibular cartilage in rats

Abstract

Objective To investigate whether mechanical stress induces mineral deposits that contribute to matrix degradation at the onset of osteoarthritis (OA) in temporomandibular joint (TMJ) cartilage. Design Female Spragueee–Dawley rats were subjected to an unilateral anterior crossbite (UAC) procedure. Histology, electron microscopy, and energy dispersive spectrometer (EDS) were used to examine cartilage matrix structures and composition of mineral deposit in the affected TMJ cartilage. Protein and/or RNA expression of phenotypic markers and mineralization modulators and matrix degradation was analyzed by immunohistochemistry and/or real-time PCR. Synthetic basic calcium phosphate (BCP) and calcium pyrophosphate dehydrate (CPPD) crystals were used to stimulate ATDC5 cells for their impact on cell differentiation and gene expression. Results Fragmented and disorganized collagen fibers, expanded fibrous spaces, and enhancement of matrix vesicle production and mineral deposition were observed in matrices surrounding hypertrophic chondrocytes in cartilage as early as 2-weeks post-UAC and exacerbated with time. The mineral deposits in TMJ cartilage at 12- and 20-weeks post-UAC had Ca/P ratios of 1.42 and 1.44, which are similar to the ratios for BCP. The expression of mineralization inhibitors, NPP1, ANK, CD73, and Matrix gla protein (MGP) was decreased from 2 to 8 weeks post-UAC, so were the chondrogenic markers, Col-2, Col-X and aggrecan. In contrast, the expression of tissue-nonspecific alkaline phosphatase (TNAP) and MMP13 was increased 4-weeks post-UAC. Treating ADTC5 cells with BCP crystals increased MMPs and ADAMTS5 expression, but reduced matrix production in a time-dependent manner. Conclusion UAC induces deposition of BCP-like minerals in osteoarthritic cartilage, which can stimulate matrix degradation by promoting the expression of cartilage-degrading enzymes to facilitate OA progression.

Prevention of Injury-Induced Osteoarthritis in Rodent Temporomandibular Joint by Targeting Chondrocyte CaSR

“…Mandibular condylar cartilage in UAC‐treated rats manifested characteristics of OA phenotypes including cartilage thinning, reduced proteoglycans content and expression of Col‐II and Aggrecan mRNA and protein, and ER swelling, as well as increased OA scores by a slightly modified OARSI scoring system . All of these OA phenotypes worsen with time of UAC treatment in both rat (Supplemental Fig.…”

“…Female Casr flox/flox littermates were subjected to the same Tam injection schedule as “control” or “Cont.” This proof‐of‐principle study only focused on female mice or rat as clinical studies showed higher prevalence of TMJ OA in female versus male patients . All KO and Cont mice were randomized into groups and subjected to UAC procedure as detailed previously, beginning immediately after the second tamoxifen injection for 3 or 7 weeks before tissue harvests and analyses. Six‐week‐old female Sprague–Dawley rats obtained from the Animal Center of the Fourth Military Medical University (FMMU) were subjected to UAC for 2, 4, or 8 weeks before tissue analyses.…”

“…Dental malocclusion can cause OA in temporomandibular joint (TMJ) . In rodents, anterior cross‐bite (UAC) imposed by dental prosthetics produces OA lesions in their TMJ cartilage as indicated by accelerated chondrocyte terminal differentiation and degradation of extracellular matrix . Herein, we first investigated the impact of biomechanical stresses on CaSR expression and terminal cell differentiation by studying the effect of fluid flow shear stress (FFSS) on isolated TMJ chondrocytes and chondrogenic ATDC5 cells.…”

Proprioceptive mechanisms in occlusion‐stimulated masseter hypercontraction

“…Therefore, in this study, we injected cholera toxin B subunit (CTb) into the inferior alveolar nerve of rats to detect its expression in the central axon terminals of Vme neurons around Vmo. We also adopted our unilateral anterior crossbite (UAC) rat model, which can induce osteoarthritic lesions in temporomandibular joints (TMJs; ), to detect changes in the expression of VGLUT1, a marker of active Vme neurons, in the crossbite mandibular incisor periodontal ligament, in Vmo, and in the masseter. The level of AChE expressed in the masseter branch was a marker of the level of motor activation.…”

Molecular changes in peripheral blood involving osteoarthritic joint remodelling

“…As we previously reported, there were slight gross morphological changes in the TMJ condyle heads of UAC‐treated Sprague Dawley (SD) rats at 12 weeks and deformations such as twisted shapes at 20 weeks. Significant mineralisation was exhibited at 12 and 20 weeks after UAC operation, which was displayed as osteochondral interface stiffening . As a result, we used the 20‐week group for the PBL mRNA microarray detections and the 12‐ and 20‐week groups to detect the TMJ and alveolar tissues for verification.…”