Recent Advances in Animal Models, Diagnosis, and Treatment of Temporomandibular Joint Osteoarthritis.

Temporomandibular joint osteoarthritis (TMJOA) is a gradual degenerative jaw joint condition. Until recent years, TMJOA is still relatively unrecognized and ineffective to be treated. Appropriate animal models with reliable detection methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. In this study, we summarized common animal models of TMJOA created by chemical, surgical, mechanical, and genetical approaches. The relevant pathological symptoms and induction mechanisms were outlined. In addition, different pathological indicators, furthermore, emerging therapeutic regimens, such as intra-articular drug delivery and tissue engineering-based approaches to treat TMJOA based on these animal models, were summarized and updated. Understanding the physiology and pathogenesis of the TMJOA, together using various ways to diagnose the TMJOA, were elaborated, including imaging techniques, molecular techniques for detecting inflammatory cytokines, histochemical staining, and histomorphometry measures. A more reliable diagnosis will enable the development of new prevention and more effective treatment strategies and thereby improve the quality of life of TMJOA patients. Impact statement Temporomandibular joint osteoarthritis (TMJOA) affects 8 to 16 percent of the population worldwide. However, TMJOA is still relatively unrecognized and ineffective to be treated in the clinic. Appropriate animal models with reliable diagnostic methods can help researchers understand the pathophysiology of TMJOA and find therapeutic options. We herein summarized common animal models of TMJOA and various ways to diagnose the TMJOA. More importantly, emerging therapeutic regimens to treat TMJOA based on these animal models were summarized. With the aid of strategies listed, more effective treatment strategies will be developed and thereby improve the life quality of TMJOA patients.

Stress Distribution of Different Pedicle Screw Insertion Techniques Following Single-Segment TLIF: A Finite Element Analysis Study.

OBJECTIVES: At present, a variety of posterior lumbar internal fixation implantation methods have been developed, which makes it difficult for spine surgeons to choose. The stress distribution of the internal fixation system is one of the important indexes to evaluate these technologies. Common insertion technologies include Roy Camille, Magerl, Krag, AO, and Weinstein insertion techniques. This study aimed to compare the distribution of von Mises stresses in different screw fixation systems established by these insertion technologies. METHODS: Here, the three-dimensional finite element (FE) method was selected to evaluate the postoperative stress distribution of internal fixation. Following different pedicle screw insertion techniques, five single-segment transforaminal lumbar interbody fusion (TLIF) models were established after modeling and validation of the L1-S1 vertebrae FE model. RESULTS: By analyzing the data, we found that stress concentration phenomenon was in all the models. Additionally, Roy-Camille, Krag, AO, and Weinstein insertion techniques led to the great stress on lumbar vertebra, intervertebral disc, and screw-rod fixation systems. Therefore, we hope that the results can provide ideas for clinical work and development of pedicle screws in the future. It is worth noting that flexion, unaffected side lateral bending, and affected side axial rotation should be limited for the patients with cages implanted. CONCLUSIONS: Overall, our method obtained the results that Magerl insertion technique was the relatively safe approach for pedicle screw implantation due to its relatively dispersive stress in TLIF models.

Intra-articular injection of clioquinol ameliorates osteoarthritis in a rabbit model.

Osteoarthritis (OA) is characterized by the degeneration of articular cartilage. Decreased autophagy is tightly associated with chondrocyte death, which contributes to the progression of OA. Thus, pharmacological activation of autophagy may be a promising therapeutic approach for OA. Here, we discovered that clioquinol, an antibiotic, significantly induces autophagy in OA chondrocytes from human tissue and rabbit model. Meanwhile, clioquinol can also augment the expression of extracellular matrix (ECM) components and suppress inflammatory mediators to improve OA microenvironment. Intra-articular injection of clioquinol can greatly prevent or slow down the development of this disease in a trauma-induced rabbit model of osteoarthritis. Such protective effect induced by clioquinol was at least in part explained by decreasing chondrocyte apoptosis and increasing autophagy. This study reveals the therapeutic potential of clioquinol in OA treatment.

Unilateral pedicle screw fixation of lumber spine: A safe internal fixation method.

Background: Unilateral pedicle screw fixation several advantages, including reduced trauma and low cost. However, its stability and safety have not been widely recognized. In this study, the biomechanical differences in the vertebral body and screw-rod system after unilateral and bilateral pedicle screw fixation were compared using both the finite element model and calf lumbar model. Method: We used the verified finite element model to establish unilateral and bilateral posterior lumbar surgery models. The biomechanical data of different parts of the models were recorded under different working states. Then, three calf lumbar models were selected to simulate different working states with the help of a universal testing machine and other instruments. Finally, the biomechanical data of the screw-rod system were obtained from a static strain test and analysis system. Results: By analyzing and comparing biomechanical data obtained using two different methods, this study found that unilateral pedicle screw fixation does not bring excessive loads to the lumbar spine and screw-rod system. Conclusion: From the perspective of biomechanics, unilateral pedicle screw fixation is considered a safe and reliable implantation technique.

[Study on adsorption of microRNA-124 by long chain non-coding RNA MALAT1 regulates osteogenic differentiation of mesenchymal stem cells].

OBJECTIVE: To investigate the regulatory effect of long chain non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) adsorbing microRNA-124 (miR-124) on osteogenic differentiation of mesenchymal stem cells (MSCs). METHODS: C3H10T1/2 cells derived from mouse embryos were cultured in vitro, then randomly divided into control group (group A), lncRNA MALAT1 no-load plasmid group (group B), lncRNA MALAT1 overexpression plasmid group (group C), lncRNA MALAT1 small interfering RNA (siRNA) group (group D), and lncRNA MALAT1 siRNA negative control group (group E). The cells were transfected into plasmids and siRNA, then induced to differentiate into osteoblasts. Alkaline phosphatase (ALP) and alizarin red staining were used to detect the osteogenic differentiation of cells in each group, real-time fluorescence quantitative (qRT-PCR) analysis was used to detect the expressions of lncRNA MALAT, miR-124, and osteogenesis-related genes such as Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and osteocalcin (OCN) in each group. Double luciferase reporter gene was used to detect the targeting regulation of lncRNA MALAT1 to miR-124. RESULTS: The relative contents of ALP positive cells, mineralized nodule, and the relative mRNA expressions of lncRNA MALAT1, Runx2, OPN, and OCN in group C were significantly higher than those in other groups ( P<0.05), while in group D significantly lower than in other groups ( P<0.05); the relative expression of miR-124 in group C was significantly lower than that in other groups( P<0.05), while in group D significantly higher than in other groups ( P<0.05). There was no significant difference in these indexes between groups A, B, and E ( P>0.05). The results of double luciferase reporter gene assay showed that lncRNA MALAT1 targeting down-regulated the expression of miR-124. CONCLUSION: LncRNA MALAT1 can targeting down-regulate the expression of miR-124 and promote the osteogenic differentiation of MSCs.

Effect of Low-Magnitude, High-Frequency Vibration Treatment on Retardation of Sarcopenia: Senescence-Accelerated Mouse-P8 Model.

Sarcopenia-related falls and fall-related injuries in community-dwelling elderly people garnered more and more interest in recent years. Low-magnitude high-frequency vibration (LMHFV) was proven beneficial to musculoskeletal system and recommended for sarcopenia treatment. This study aimed to evaluate the effects of LMHFV on the sarcopenic animals and explore the mechanism of the stimulatory effects. Senescence-accelerated mouse P8 (SAMP8) mice at month 6 were randomized into control (Ctrl) and vibration (Vib) groups and the mice in the Vib group were given LMHFV (0.3 g, 20 min/day, 5 days/week) treatment. At months 0, 1, 2, 3, and 4 post-treatment, muscle mass, structure, and function were assessed. The potential proliferation capacity of the muscle was also evaluated by investigating satellite cells (SCs) pool and serum myostatin expression. At late stage, the mice in the Vib group showed higher muscle strength (month 4, p = 0.028). Generally, contractibility was significantly improved by LMHFV (contraction time [CT], p = 0.000; half-relaxation time [RT50], p = 0.000). Enlarged cross-sectional area of fiber type IIA was observed in the Vib group when compared with Ctrl group (p = 0.000). No significant difference of muscle mass was observed. The promotive effect of LMHFV on myoregeneration was reflected by suppressed SC pool reduction (month 3, p = 0.000; month 4, p = 0.000) and low myostatin expression (p = 0.052). LMHFV significantly improved the structural and functional outcomes of the skeletal muscle, hence retarding the progress of sarcopenia in SAMP8. It would be a good recommendation for prevention of the diseases related to skeletal muscle atrophy.

Bone cement solidifiliation influence the limb alignment and gap balance during TKA.

INTRODUCTION: Mechanical alignment deviation after total knee arthroplasty is a major reason for early loosening of the prosthesis. Achieving optimum cement penetration during fixation of the femoral and tibial component is an essential step in performing a successful total knee arthroplasty. Bone cement is used to solidify the bone and prosthesis. Thickness imbalance of bone cement leads to the deviation of mechanical alignment. To estimate the influence of bone cement, a retrospective study was conducted. MATERIALS AND METHODS: A total of 36 subjects were studied. All the TKA were performed following the standard surgical protocol for navigated surgery by medial approach with general anaesthesia. Prostheses were fixed by bone cement. RESULTS: We compared the mechanical axis, flexion/extension, and gap balance before and after cementation. All the factors were different compared with those before and after cementation. Internal rotation was reached with statistical significance (P=0.03). CONCLUSION: Bone cement can influence the mechanical axis, flexion/extension, and gap balance. It also can prompt us to make a change when poor knee kinematics were detected before cementation.