Rabbit Temporomandibular Joint Research Articles

Can intra-articular daidzein injection reduce oxidative damage and early osteoarthritis in a rabbit temporomandibular joint model?

BackgroundOxidative damage and inflammatory cytokines in osteoarthritis (OA) exacerbate the disease course. Daidzein (DZ) has antioxidant and anti-inflammatory effects. This study evaluated the early histopathological effects of intra-articular daidzein injection on experimentally induced osteoarthritis in rabbit TMJs.MethodsThe predictor variable was intra-articular injection of DZ or a saline control. 50 µl of 3 mg/mL MIA solution was injected into the right TMJ of 16 New Zealand rabbits to induce experimental OA. One rabbit was sacrificed after 4 weeks to confirm the formation of the OA model and the OA model was obtained. The remaining 15 rabbits were randomly divided into 2 groups: an experimental group (9 rabbits) and a control group (6 rabbits). On days 1, 7, 14, and 21; 50 µl of saline solution was applied to the right TMJ of the control group and 50 µl daidzein solution (1.8 mg/ml) was applied to the right TMJ to the experimental group. After one week from the date of the last injection, the rabbits were sacrificed, and histopathological and biochemical evaluations were performed. The Shapiro-Wilk test was used to evaluate whether the variables in the study conformed to normal distribution. Mean ± SD (standard deviation) or median (interquartile range (IQR)) was used to show the descriptive statistics of the variables. T-test and Mann Whitney U test were used to compare the control and experimental groups for biochemical changes. The chi-square test was used to show the distribution of histopathological changes variables obtained within the scope of the study based on control and experimental groups. A P-value < 0.05 was considered significant for all evaluations.ResultsThere were 8 and 6 animate treated with DZ and saline, respectively. There was no statistically significant difference between groups in articular cartilage (p = 0.3), osteochondral junction (p = 0.3), subchondral bone structure (p = 1.0) or chondrocyte appearance (p = 0.4). The experimental group showed significantly lower mean values for Total Oxidant Status (TOS) (p = 0.002) and Oxidative Stress Index (OSI) (p = 0.007).ConclusionsAn intra-articular DZ injection appears to show limited reduction of oxidative damage and early OA in the rabbit TMJ. DZ might represent a promising natural compound with beneficial effects in the management of TMJ-OA.

Gelatin methacryloyl hydrogel with and without dental pulp stem cells for TMJ regeneration: An invivo study in rabbits.

In the last decade, tissue-engineering strategies for regenerating the temporomandibular joint (TMJ) have been investigated. This may be a promising strategy for the minimally invasive restoration of joint integrity. To evaluate whether dental pulp stem cells (DPSCs) loaded in a light-occured hydrogel made of gelatin methacryloyl (GelMA) enhance the regeneration of osteochondral defects in the rabbit TMJ. Defects were filled with GelMA alone (control group; n = 4) or filled with GelMA loaded with rabbit DPSCs (experimental group; n = 4), In one group, the TMJ capsule was opened without creating a defect (sham group; n = 2). The following micro-CT parameters were analysed: bone volume to total volume ratio (BV/TV%) and bone mineral density (BMD). Histological evaluation was performed to assess cartilage regeneration features. A semi-quantitative scoring system was also used to evaluate the defects. All groups had no statistical difference regarding the micro-CT parameters. The highest mean healing score was found for the experimental group. After 4 weeks, there were no signs of hydrogel in either group or no signs of inflammation in the adjacent tissues. The tissue formed in the defect was dense fibrous connective tissue. Adding DPSCs to GelMA did not provide a regenerative enhancement in TMJ osteochondral defects. This resulted in similar micro-CT parameters after 4 weeks of healing, with improved signs of subchondral bone regeneration but no cartilage regeneration.

Bulk RNA-seq analyses of mandibular condylar cartilage in a post-traumatic TMJ osteoarthritis rabbit model.

The temporomandibular joint (TMJ) is anatomically comprised of the mandibular condylar cartilage (CC) lined with fibrocartilaginous superficial zone and is crucial for eating and dental occlusion. TMJ osteoarthritis (OA) leads to pain, joint dysfunction and permanent loss of cartilage tissue. However, there are no drugs clinically available that ameliorate OA and little is known about global profiles of genes that contribute to TMJ OA. Furthermore, animal models that recapitulate the complexity of signalling pathways contributing to OA pathogenesis are crucial for designing novel biologics that thwart OA progression. We have previously developed a New Zealand white rabbit TMJ injury model that demonstrates CC degeneration. Here, we performed genome-wide profiling to identify new signalling pathways critical for cellular functions during OA pathology. Temporomandibular joint OA was surgically induced in New Zealand white rabbits. Three months following injury, we performed global gene expression profiling of the TMJ condyle. RNA samples from TMJ condyles were subjected to sequencing. After raw RNA-seq data were mapped to relevant genomes, differential expression was analysed with DESeq2. Gene ontology enrichment analysis and Kyoto Encyclopedia of Genes and Genomes pathway analysis were conducted. Our study revealed multiple pathways altered during TMJ OA induction including the Wnt, Notch and PI3K-Akt signalling pathways. We demonstrate an animal model that recapitulates the complexity of the cues and signals underlying TMJ OA pathogenesis, which is essential for developing and testing novel pharmacologic agents to treat OA.

Ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix improves rabbit temporomandibular joint osteoarthrosis

ABSTRACT Objective: To investigate whether and how ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix can improve rabbit temporomandibular joint osteoarthrosis. Method: Isolate and culture adipose stem cells, measure the activity of differentiated chondrocytes by MTT assay and expression of type II collagen in these cells by immunohistochemistry, in order to evaluate the effect of ginsenoside Rg1 on adipose stem cell proliferation and differentiation into chondrocytes.32 New Zealand white rabbits were randomly divided into four groups: blank group, model group, control group and experimental group, 8 in each group. Osteoarthritis model was established by intra-articular injection of papain. Two weeks after successful model building, medication was given for the rabbits in control group and experimental group. 0.6 mL ginsenoside Rg1/ ADSCs suspension was injected into superior joint space for the rabbits in control group, once a week; 0.6 mL ginsenoside Rg1/ ADSCs complex was injected for the rabbits in experimental group, once a week. Results: Ginsenoside Rg1 can promote ADSCs-derived chondrocytes’ activity and expression of type II collagen. Scanning electron microscopy histology images showed cartilage lesions of the experimental group was significantly improved in comparison with control group. Conclusion: Ginsenoside Rg1 can promote ADSCs differentiate into chondrocytes, and Ginsenoside Rg1/ADSCs supplemented with hyaluronic acid as the matrix can significantly improve rabbit temporomandibular joint osteoarthrosis.

Decellularized-disc based allograft and xenograft prosthesis for the long-term precise reconstruction of temporomandibular joint disc.

Currently, no effective disc reconstruction treatment strategy is clinically available for temporomandibular joint (TMJ) disc-related diseases. To address this, we developed a prosthesis construct with laser-drilled decellularized natural disc reinforced by polycaprolactone, which mimics the natural morphology, and structural, biomechanical and biological property of the TMJ disc. The construct demonstrated good biocompatibility, safety and immunological tolerance both in vitro, and in a rat subcutaneous model. During 6 months implantation in an allogeneic rabbit TMJ disc reconstruction model, the disc prosthesis maintained its integrity, collagen fiber-orientation, mechanical property, joint structural stability and prevented articular cartilage and bone from damage. Furthermore, the "upgraded" disc prosthesis obtained from decellularized porcine disc was implanted into a goat TMJ disc reconstruction model. The xenograft prosthesis, with strength and viscoelasticity similar to a natural TMJ disc, was able to restore the structure and function of TMJ up to 20 weeks. These results demonstrate the translational feasibility of an allogeneic or xenogeneic decellularized disc prosthesis for treatment of advanced TMJ disc-related diseases. STATEMENT OF SIGNIFICANCE: This study makes a significant contribution to TMJ disc disease treatment both in theory and in clinics, because: (1) it provided an innovative approach to prepare an artificial TMJ disc with decent mechanical properties and long-term condyle-protecting effect; (2) it specified an advanced decellularized method for fibrocartilage decellularization and xenograft application; (3) it developed a facile and reproducible TMJ disc reconstruction model not only for middle size animal but also for large animal study; (4) the comprehensive and unreported biomechanical tests on the natural TMJ discs would act as a valuable reference for further research in the field of artificial TMJ disc materials or TMJ disc tissue engineering; (5) it suggested a potential treatment for patients with severe TMJ diseases that were commonly met but difficult to treat in clinics.

Biomimetic construction of a lubricious hydrogel with robust mechanics via polymer chains interpenetration and entanglement for TMJ disc replacement

Developing a temporomandibular joint (TMJ) disc substitute with reliable long-term functional support has faced a huge challenge in replicating the unique microarchitecture, biomechanics and lubrication of the natural tissue. Herein, a novel biomimetic hydrogel consisting of graphene oxide nanosheets modified anionic polyurethane (nGO-APU) and polyvinyl alcohol (PVA) was successfully fabricated through combined freeze-thawing and annealing treatment. Of which, the annealed PVA (a-PVA) with entanglement network acted as the main frame to provide mechanical support, while the interpenetrated nGO-APU chains endowed the function for water retention and lubrication, thus resisting the compressive loads and fulfilling a durable energy absorbing and cushion. The resultant nGO-APU/a-PVA hydrogel achieved better lubrication effect through the synergistic effect of fluid film and boundary lubrication, exhibiting a low friction coefficient of about 0.06, close to the natural TMJ disc. After implantation into rabbit TMJ for up to 24 weeks, the nGO-APU/a-PVA hydrogel kept the structural stability to offer effective protection against wearing of the cartilage, meanwhile ameliorating the worsening of osteoarthritis. The finite element analysis (FEA) further proved that the resultant hydrogel could effectively disperse the applied stress and dissipate energy under practical loading conditions. This strategy based on a biomimetic hydrogel with enhanced mechanical stability and lubrication performance shows clinical promise for TMJ disc replacement.

Evaluation of the Anti-inflammatory Effect of Intra-articular Injection of Chondroitin Sulfate and Sodium Hyaluronate in Mechanically Induced Temporomandibular Joint Injury in Rabbits

BACKGROUND: Degenerative arthritis is the most common form of arthritis, usually affecting the hands, feet, spine, knees, and temporomandibular joint (TMJ) as well. TMJ degenerative arthritis causes symptoms of painful joints, loss of joint function, limited mouth opening, joint instability, and clicking. Non-surgical symptomatic treatments can successfully be used to treat patients with degenerative arthritis. AIM: This study aimed to evaluate the anti-inflammatory effect of intra-articular injection of chondroitin sulfate and sodium hyaluronate in mechanically induced acute injury in TMJ of rabbits. METHODS: An animal study was conducted, all rabbits received a mechanical injury using a contra-angle handpiece with a speed of 120 rpm of a fissure bur 4 mm in diameter and 4 mm in depth extending to subchondral bone. Thirty-two rabbits were randomized into four groups: Control group, sodium hyaluronate “SH” group, chondroitin sulfate “CS” group, and “CS-SH” group. After 7 days, rabbits in the control group, “SH” group, “CS” group, and “CS-SH” group were respectively treated with normal saline, sodium hyaluronate, chondroitin sulfate, or combination of CS&amp;SH injection in the TMJ. All animals were treated once weekly for 3 weeks. A histological evaluation was performed. RESULTS: Histological findings showed a significantly reduced inflammatory cell, bone resorption, and fibrosis in the CS-HA-treated group. CONCLUSION: CS-SH injection has an anti-inflammatory effect on TMJ degenerative arthritis and aids in the reparative process.

Inflammation-Stimulated MSC-Derived Small Extracellular Vesicle miR-27b-3p Regulates Macrophages by Targeting CSF-1 to Promote Temporomandibular Joint Condylar Regeneration.

Small extracellular vesicles (sEVs) secreted by mesenchymal stem cells (MSCs) have been extensively studied in recent years. sEV contents change with the secreting cell state. When MSCs are exposed to an inflammatory environment, they release more functional growth factors, exosomes, and chemokines. Herein, MSCs are stimulated to alter sEV cargos and functions to regulate the inflammatory microenvironment and promote tissue regeneration. Sequencing of sEV miRNAs shows that certain RNAs conducive to cell function are upregulated. In this study, in vitro cell function experiments show that both inflammation-stimulated adipose-derived MSC (ADSC)-derived sEV (IAE) and normal ADSC-derived sEV (AE) promote cell proliferation; IAE also significantly improves cell migration. Regarding macrophage polarization regulation, IAE significantly promotes M2 macrophage differentiation. RNA-sequencing analysis indicates that high miR-27b-3p expression levels in IAE may regulate macrophages by targeting macrophage colony-stimulating factor-1 (CSF-1). In vivo, a rabbit temporomandibular joint (TMJ) condylar osteochondral defect model shows that both AE and IAE promote TMJ regeneration, with IAE having the most significant therapeutic effect. Therefore, the authors confirm that exposing MSCs to an inflammatory environment can feasibly enhance sEV functions and that modified sEVs achieve better therapeutic effects.

Chondrotoxic effects of intra-articular injection of local anaesthetics in the rabbit temporomandibular joint

The aim of this study was to investigate the chondrotoxic effects of a single-dose intra-articular injection of articaine, lidocaine, and bupivacaine on the rabbit temporomandibular joint (TMJ). Twenty-four rabbits were divided into four groups: control (group 1), articaine (group 2), lidocaine (group 3), and bupivacaine (group 4). Synovial fluid samples and venous blood were taken to evaluate matrix metalloproteinase 3 (MMP-3) levels. One millilitre of local anaesthetic solution was injected in the study groups and saline solution in the control group. The rabbits were euthanized after 4 weeks and the mandibular condyles and articular discs were evaluated. On histological examination, the study group samples had irregular joint surfaces, decreased collagen, and a thinner cartilage layer. Apoptotic cells were evaluated with the TUNEL method. TUNEL-positive apoptotic cell counts were higher in all study groups compared to the control group, and the difference was significant (P < 0.001). The mean preoperative serum MMP-3 level for all groups was 5.71 ± 3.33 ng/mL, while the mean postoperative level was 22.61 ± 6.36 ng/mL; this difference was significant (P < 0.001). A single-dose intra-articular injection of local anaesthetic had apoptotic effects on chondrocytes, leading to degenerative changes in the TMJ articular structures. Articaine was found to have less harmful effects than lidocaine and bupivacaine. Intra-articular injection of local anaesthetics should be limited in the TMJ because of the potential toxic effects.

A rabbit model to investigate temporomandibular joint osteochondral regeneration

The objective of this study was 2-fold: (1) to describe the rabbit temporomandibular joint (TMJ) anatomy and (2) to provide a detailed, step-by-step description of a minimally invasive approach to perform a standard osteochondral TMJ defect that can be used to investigate the regenerative potential of biomaterials. This study was performed in 2 steps. In the first, a total of 8 rabbit carcasses (n=16 joints) were used to study the normal TMJ anatomy and histology to develop a minimally invasive approach to access the articulating surface of the condyle to perform a standard osteochondral defect. In the second, the surgical procedure was performed in 10 live animals to evaluate the feasibility of the model and to evaluate the regenerative potential of a biodegradable light-cured hydrogel seeded with stem cells (results not shown). The cartilage of the mandibular condyle showed 4 layers: fibrous, proliferative, hypertrophic, and a zone of calcified cartilage. Positive safranin O staining was observed in the cartilage. The mean duration of the procedure (from incision to last stitch) was 35.5 (±9.21) minutes. All animals survived the procedures without any major complications. This animal model represents an easy and nonmorbid surgical approach to rabbit TMJ.

Human Salivary Histatin-1-Functionalized Gelatin Methacrylate Hydrogels Promote the Regeneration of Cartilage and Subchondral Bone in Temporomandibular Joints.

The avascular structure and lack of regenerative cells make the repair of osteochondral defects in the temporomandibular joint (TMJ) highly challenging in the clinic. To provide a viable treatment option, we developed a methacrylated gelatin (Gel-MA) hydrogel functionalized with human salivary histatin-1 (Hst1). Gel-MA is highly biocompatible, biodegradable, and cost-effective. Hst1 is capable of activating a series of cell activities, such as adhesion, migration, differentiation, and angiogenesis. To evaluate the efficacy of Hst1/Gel-MA, critical-size osteochondral defects (3 mm in diameter and 3 mm in depth) of TMJ in New Zealand white rabbits were surgically created and randomly assigned to one of the three treatment groups: (1) control (no filling material); (2) Gel-MA hydrogel; (3) Hst1/Gel-MA hydrogel. Samples were retrieved 1, 2, and 4 weeks post-surgery and subjected to gross examination and a series of histomorphometric and immunological analyses. In comparison with the control and Gel-MA alone groups, Hst1/Gel-MA hydrogel was associated with significantly higher International Cartilage Repair Society score, modified O’Driscoll score, area percentages of newly formed bone, cartilage, collagen fiber, and glycosaminoglycan, and expression of collagen II and aggrecan. In conclusion, Hst1/Gel-MA hydrogels significantly enhance bone and cartilage regeneration, thus bearing promising application potential for repairing osteochondral defects.

Low-intensity pulsed ultrasound inhibits IL-6 in subchondral bone of temporomandibular joint osteoarthritis by suppressing the TGF-β1/Smad3 pathway

ObjectiveThis study aimed to provide further information on the exact mechanisms involved in the anti-inflammatory effect of low-intensity pulsed ultrasound (LIPUS) on rabbit temporomandibular joint osteoarthritis (TMJOA) on interleukin-6 (IL-6) production in subchondral bone, IL-6 production in IL-1β stimulated via inhibition of the TGF-β1/Smad3 pathway in mouse embryo osteoblast precursor (MC3T3-E1) cells. DesignBilateral joints were injected with type II collagenase to establish TMJOA models in two male and four female rabbits. The left joint was continuously stimulated by LIPUS, while the right joint was treated with the power off in this model. One male and two female rabbits were used as normal healthy controls without treatment. The histological features of subchondral bone were examined by Safranin‐O/Fast staining. Immunohistochemistry was conducted to evaluate IL-6 expression. Then, cells were stimulated by LIPUS with IL-1β. IL-6 expression and activity of the TGF-β1/Smad3 pathway were evaluated by Enzyme-linked immunosorbent assay (ELISA), Immunofluorescence and Western blotting, respectively. Specific inhibition of the TGF-β1/Smad3 pathway was conducted by transfecting with small interfering RNA (siRNA) of type II receptor (siTβRII). ResultsLIPUS significantly ameliorated the production of IL-6 in vitro and in vivo. Its inhibitory effect on the production of IL-6 induced by IL-1β in MC3T3-E1 cells was partly reversed by siTβRII knockdown. ConclusionsLIPUS inhibited IL-6 production by suppressing the TGF-β1/Smad3 pathway of subchondral bone in TMJOA. These data revealed the part of the pathways involved in the anti-inflammatory effect of LIPUS and provided a possible treatment strategy for TMJOA patients and other inflammatory diseases.

Effects of low and high molecular weight hyaluronic acid on the osteoarthritic temporomandibular joint in rabbit.

To compare the effect between intra-articular infiltration of low molecular weight (LMW-HA) and high molecular weight hyaluronic acid (HMW-HA) on the histopathological characteristics of the cartilage and disc of the temporomandibular joint (TMJ) osteoarthritis (OA) induced in rabbits. An experimental study was conducted on 38 rabbit TMJs. The effect of different hyaluronic acids was compared at 30 and 135days. Histopathological analysis was performed. Cartilage damage was assessed with the OARSI scale. The severity of the induced OA according to OARSI was 3.4 degrees in the mandibular condyle (MC) and 3.2 in the mandibular fossa (MF); the articular disc (AD) presented disorganization of the collagen fibers, with randomly arranged hypertrophic chondrocytes. At 30days, untreated TMJs worsened. TMJ treated with LMW-HA reduced its severity to 1.5 degrees in MC and 1.6 in MF, the AD presented histological aspects within normal limits. TMJ treated with HMW-HA presented 2.4 degrees in MC and 2.2 in MF, the AD maintained characteristics similar to the group with OA. At 135days, all groups worsened. Exogenous HA is effective in the management of TMJ-OA induced in rabbits, showing cartilage and articular disc repair at 30days. The LMW-HA group had better effects on joint tissue than HMW-HA 30days after treatment. However, at 135days, both groups presented regression of joint tissue repair. HA is effective in the anti-arthritic treatment of TMJ-OA induced in rabbits; LMW-HA shows better results in cartilage and articular disc repair than HMW-HA.

Study of treatment with hyaluronic acid combined with platelet rich plasma in the in vivo regeneration of defects in articular discs of temporomandibular joint

The aim of this study was to evaluate the in vivo repair using an experimental model of osteoarthritis of the temporomandibular joint in rabbits, treated with hyaluronic acid (HA), isolated or combined with platelet rich plasma (PRP). Forty New Zealand rabbits were divided into 4 groups: G1 - normal TMJ, G2 - lesion / untreated, G3 - lesion / HA, and G4 - lesion / PRP + HA. The disc and the condyle were evaluated using radiographies, macro and microscopic analysis through routine histotechnique, Picrosirius red staining and immunohistochemistry. The results were evaluated by descriptive and inferential statistics. Macroscopically, the disc in the treated groups presented, in most of the specimens, partial or total filling of the defect. Histological analysis confirmed the presence of mineralized material, near and distant perforation, as well as decreased cellularity and fibrosis. The collagen I was demonstrated in higher amounts when compared to type III collagen, independently of the group and period evaluated; in the condyle, G3 and G4 presented significant higher percentage of type I collagen, than G2. In conclusion, the groups that were treated with HA and PRP combined with HA presented no significant differences in microscopic pattern. The macroscopic finding that in some samples in HA treated group and one sample in PRP + HA group presented complete filling of the perforation let us to conclude that new experiments adding more sensitive methods may clear the influence of these treatments in reduce the damage in the osteochondral surface related the lesioned disc.

Effects of Prolotherapy with Organic Silicon in Temporomandibular Joint in Rabbits

Effects of Prolotherapy with Organic Silicon in Temporomandibular Joint in Rabbits

Reduction of osteoarthritis severity in the temporomandibular joint of rabbits treated with chondroitin sulfate and glucosamine.

Osteoarthritis is a degenerative disease that causes substantial changes in joint tissues, such as cartilage degeneration and subchondral bone sclerosis. Chondroitin sulfate and glucosamine are commonly used products for the symptomatic treatment of osteoarthritis. The aim of the present study was to investigate the effects of these products when used as structure-modifying drugs on the progression of osteoarthritis in the rabbit temporomandibular joint. Thirty-six New Zealand rabbits were divided into 3 groups (n = 12/group): control (no disease); osteoarthritis (disease induction); and treatment (disease induction and administration of chondroitin sulfate and glucosamine). Osteoarthritis was induced by intra-articular injection of monosodium iodoacetate. Animals were killed at 30 and 90 days after initiation of therapy. The treatment was effective in reducing disease severity, with late effects and changes in the concentration of glycosaminoglycans in the articular disc. The results indicate that chondroitin sulfate and glucosamine may have a structure-modifying effect on the tissues of rabbit temporomandibular joints altered by osteoarthritis.

Therapeutic effect of mesenchymal stem cells derived from human umbilical cord in rabbit temporomandibular joint model of osteoarthritis

Osteoarthritis (OA) is a degenerative condition of the temporomandibular joint (TMJ) characterised by chronic inflammation and damage to joint structures. Because of the complexity of TMJ-OA, only symptomatic treatments are currently available. Recent reports have shown that many of stem cells can exert anti-inflammatory and tissue-regenerating effects. In this study, we investigated the potential cartilage-regenerating and anti-inflammatory effects of human umbilical cord matrix-mesenchymal stem cells (hUCM-MSCs) for the treatment of TMJ-OA. hUCM-MSC lines, isolated from different donors, which showed different activities in vitro. Using a selected cell line, we used different concentrations of hUCM-MSCs to assess therapeutic effects in a rabbit model of monosodium iodoacetate-induced TMJ-OA. Compared with the untreated control group, the potential regenerative result and anti-inflammatory effects of hUCM-MSCs were evident at all the tested concentrations in rabbits with induced TMJ-OA. The median dose of hUCM-MSCs showed the prominent cartilage protective effect and further cartilage regeneration potential. This effect occurred via upregulated expression of growth factors, extracellular matrix markers, and anti-inflammatory cytokines, and reduced expression of pro-inflammatory cytokines. The anti-inflammatory effect of hUCM-MSCs was comparable to that of dexamethasone (DEX). However, only hUCM-MSCs showed potential chondrogenesis effects in this study. In conclusion, our results indicate that hUCM-MSCs may be an effective treatment option for the treatment of TMJ-OA.

A novel construct with biomechanical flexibility for articular cartilage regeneration

BackgroundAlthough tissue-engineered cartilage has been broadly studied, complete integration of regenerated cartilage with residual cartilage is still difficult for the inferior mechanical and biochemical feature of neocartilage. Chondrogenesis of mesenchymal stem cells can be induced by biophysical and biochemical factors.MethodsIn this study, autologous platelet-rich fibrin (PRF) membrane was used as a growth factor-rich scaffold that may facilitate differentiation of the transplanted bone marrow mesenchymal stem cells (BMSCs). At the same time, hydrostatic pressure was adopted for pre-adjustment of the seed cells before transplantation that may promote the mechanical flexibility of neocartilage.ResultsAn in vitro study showed that the feasible hydrostatic pressure stimulation substantially promoted the chondrogenic potential of in vitro-cultured BMSC/PRF construct. In vivo results revealed that at every time point, the newborn tissues were the most favorable in the pressure-pretreated BMSC/PRF transplant group. Besides, the transplantation of feasible hydrostatic pressure-pretreated construct by BMSC sheet fragments and PRF granules could obviously improve the integration between the regenerated cartilage and host cartilage milieu, and thereby achieve boundaryless repair between the neocartilage and residual host cartilage tissue in rabbit temporomandibular joints. It could be concluded that feasible hydrostatic pressure may effectively promote the proliferation and chondrogenic differentiation of BMSCs in a BMSC/PRF construct.ConclusionThis newly formed construct with biomechanical flexibility showed a superior capacity for cartilage regeneration by promoting the mechanical properties and integration of neocartilage.

Low-intensity pulsed ultrasound repair in mandibular condylar cartilage injury rabbit model

ObjectivesBeneficial effects of low-intensity pulsed ultrasound(US) have been reported for knee articular cartilage injury. It is unclear whether the same effect could be observed on mandibular condylar cartilage. This study was designed to explore the efficacy of ultrasound cartilage repair via autophagy regulation. MethodsA total of 18 adult rabbits were divided into a sham operation group (exposure to condylar articular surface only), operation without US group (only cartilage surgery), and operation with US group (received ultrasonic therapy daily on day 4 after cartilage surgery). The rabbits were then sacrificed to construct a temporomandibular joint (TMJ) cartilage injury model and HE staining was conducted to observe pathological changes of cartilage in each group. Expression of FGF18, FGFR4, beclin1, ATG3 and ATG7 in rabbit TMJ cartilage were detected using RT-PCR and western blotting. Finally, protein-protein interaction (PPI) analysis was used to observe the interaction among the network of important biomarkers in this injury model. ResultsCompared to the operation without US group, the severity of cartilage injury was decreased in the operation with US group according to HE staining. The expression of autophagy biomarkers, beclin1, ATG3, ATG7, FGF18 and FGFR4, in operation with US group were up-regulated compared with those in sham operation group and operation without US group p < 0.05). In PPI analysis, ATG3, ATG7, PIK3C3, PIK3R4, BECN1 were identified as hub nodes connecting with most proteins network. ConclusionsOur results suggest US has therapeutic potential for the treatment of mandibular condylar cartilage injury, and may affect chondrocyte autophagy.

Temporomandibular joint arthrocentesis in a rabbit model: technique and recommendations in the study of temporomandibular disorders.

Arthrocentesis has been used in the temporomandibular joint (TMJ) to analyze components of the synovial fluid or as a therapeutic procedure associated or not with the administration of a drug. The rabbit is one of the most commonly used animal species as a model for pathologies that affect the TMJ. The aim of this study was to propose a specific technique to perform arthrocentesis on the rabbit TMJ, emphasizing descriptions of reference points and measurements for a successful puncture without complications. Fourteen adult rabbits (Oryctolagus cuniculus) were used. The project was approved by the Scientific Ethics Committee of the Universidad de La Frontera (File Nº083/2016). The description of the technique was divided into three steps: 1) Location of the rabbit TMJ, 2) Positioning of the needles in the TMJ, and 3) Passage of fluid through the TMJ. This arthrocentesis technique could help to simplify the procedure and give the investigator a guide for joint washing and extraction of synovial fluid in the rabbit TMJ.