Site specific changes in gene expression and cartilage metabolism during early experimental osteoarthritis

Epigenetic PPARγ preservation attenuates temporomandibular joint osteoarthritis

OBJECTIVE

Previous studies have demonstrated that PPARγ deficiency is associated with osteoarthritis in the knee joint. However, whether epigenetic PPARγ dysregulation has any effect on temporomandibular joint osteoarthritis (TMJOA) is unknown. This study aims to determine the role and mechanism of epigenetic PPARγ dysregulation in TMJOA.

METHODS

Partial TMJ discectomy was performed to induce TMJOA in rat. Primary condylar chondrocytes were isolated, and TNF-α-induced inflammatory condition was created in vitro. The expressions of PPARγ and DNA methyltransferase were investigated in vivo and in vitro. The association of PPARγ and DNA methylation was further studied by treating chondrocytes with DNA demethylation agent 5-Aza-2'-deoxycytidine (5Aza) and transfecting with siRNA of DNA methyltransferase (DNMT)1 and DNMT3a, and the methylation level of PPARγ promoter was evaluated by Bisulfite-sequencing PCR. The chondroprotective effects of 5Aza were explored in vitro and in vivo.

RESULTS

PPARγ suppression and upregulated DNMT1/DNMT3a expression exist in TMJOA cartilage in vivo and primary condylar chondrocytes under TNF-α-induced inflammatory conditions in vitro. DNMT1 and DNMT3a elevation contributes to PPARγ-promoter hypermethylation in TMJ chondrocytes under TNF-α-induced inflammation conditions. DNA demethylation intervention by 5Aza protects chondrocytes from inflammation response in vitro. Mechanistically, 5Aza reversed the hypermethylation of the PPARγ promoter and subsequently resulted in PPARγ restoration and decreased expression of cartilage-catabolic factors in chondrocytes. Rat TMJOA model revealed that 5Aza, by reversing PPARγ suppression, effectively attenuated cartilage degeneration and stabilized cartilage homeostasis by balancing anabolic factor and catabolic factor expression.

CONCLUSION

Epigenetic PPARγ suppression may play a causal role in TMJOA pathogenesis, which can be alleviated by DNA demethylation with 5Aza treatment. This study provides new insights into the pathogenic mechanism and therapeutic strategy of TMJOA.

Development of a Novel Rat Knee Osteoarthritis Model Induced by Medial Meniscus Extrusion

OBJECTIVE

The medial meniscus extrusion (MME) is associated with increased stress on the knee joint, which leads to cartilage degeneration. To evaluate the etiology of knee osteoarthritis, it is extremely important to create animal models of the disease that more closely resemble actual clinical conditions in terms of symptomatology, molecular biology, and histology. This study aimed to create a clinically relevant model of MME in rats.

DESIGN

Behavioral, molecular biological, and histological changes in the newly developed rat MME model were compared with those in sham and medial meniscus transection and medial collateral ligament transection (MMT) models to examine the characteristics of this model.

RESULTS

In the MME rat model, behavioral evaluation shows abnormalities in gait compared with the other 2 groups, and molecular biological evaluation of the infrapatellar synovia of rats shows that gene expression of inflammatory cytokines, matrix-degrading enzymes, and pain-related nerve growth factor was increased compared with the sham group. Furthermore, histological evaluation reveals that cartilage degeneration was the most severe in the MME group.

CONCLUSIONS

The newly developed MME model reproduced the characteristic pathology of MME in clinical practice, such as severe pain, inflammation, and rapid progression of osteoarthritis. The MME model, which might more closely mimic human knee osteoarthritis (OA), could be a useful model for elucidating the pathophysiology and considering therapeutic management for knee OA.

Pathological Characteristics of Monosodium Iodoacetate-Induced Osteoarthritis in Rats

BACKGROUND

This study aimed to identify pain-related behavior and pathological characteristics of the knee joint in rats with monosodium iodoacetate (MIA)-induced osteoarthritis (OA).

METHODS

Knee joint inflammation was induced by intra-articular injection of MIA (4 mg/50 µL, n = 14) in 6-week-old male rats. Knee joint diameter, weight-bearing percentage on the hind limb during walking, the knee bending score, and paw withdrawal to mechanical stimuli were measured to evaluate edema and pain-related behavior for 28 d after MIA injection. Histological changes in the knee joints were evaluated using safranin O fast green staining on days 1, 3, 5, 7, 14, and 28 after OA induction (n = 3, respectively). Changes in bone structure and bone mineral density (BMD) were examined 14 and 28 d after OA (n = 3, respectively) using micro-computed tomography (CT).

RESULTS

The knee joint diameter and knee bending scores of the ipsilateral joint significantly increased 1 d after MIA injection, and the increased knee joint diameter and knee bending score persisted for 28 d. Weight-bearing during walking and paw withdrawal threshold (PWT) decreased from 1 and 5 d, respectively, and were maintained up to 28 d after MIA. Cartilage destruction started on day 1, and Mankin scores for bone destruction significantly increased for 14 d, as shown by micro-CT imaging.

CONCLUSION

The present study demonstrated that histopathological structural changes in the knee joint due to inflammation started soon after MIA injection, which induced OA pain from inflammation-related acute pain to spontaneous and evoked associated chronic pain.

Dioscin alleviates the progression of osteoarthritis: an in vitro and in vivo study

Osteoarthritis (OA) is a common joint disease and is the main cause of physical disability in the elderly. Currently, there is no adequate therapeutic strategy to reverse the progression of OA. Many natural plant extracts have received attention in the treatment of OA due to their potential anti-inflammatory properties, and reduced incidence of adverse events. Dioscin (Dio), a natural steroid saponin, has been demonstrated to inhibit the release of inflammatory cytokines in mouse and rat models of various diseases, and has a protective effect in chronic inflammatory diseases. However, whether Dio alleviates OA progression remains to be explored. In this research, our purposes were to investigate the therapeutic potential of Dio in OA. The results demonstrated that Dio exerted anti-inflammatory effects by repressing NO, PGE₂, iNOS and COX-2. Moreover, the application of Dio could repress IL-1β-induced overexpression of matrix metalloproteinases (MMPs, including MMP1, MMP3, and MMP13) and ADAMTS-5, and improve the synthesis of collagen II and aggrecan, which contribute to the maintenance of chondrocyte matrix homeostasis. The underlying mechanism involved the inhibition of the MAPK and NF-κB signaling pathways by Dio. Furthermore, the treatment of Dio significantly improved the pain behaviors of rat OA models. The in vivo study revealed that Dio could ameliorate cartilage erosion and degradation. These results collectively indicate that Dio can be used as a promising and effective agent for the therapy of OA.

Flavokawain A alleviates the progression of mouse osteoarthritis: An in vitro and in vivo study

Osteoarthritis (OA) is one of the most prevalent chronic degenerative joint diseases affecting adults in their middle or later years. It is characterized by symptoms such as joint pain, difficulty in movement, disability, and even loss of motion. Moreover, the onset and progression of inflammation are directly associated with OA. In this research, we evaluated the impact of Flavokawain A (FKA) on osteoarthritis. In-vitro effects of FKA on murine chondrocytes have been examined using cell counting kit-8 (CCK-8), safranin o staining, western blot, immunofluorescence staining, senescence β-galactosidase staining, flow cytometry analysis, and mRFP-GFP-LC3 adenovirus infection. An in-vivo model of destabilization of the medial meniscus (DMM) was employed to investigate FKA's effect on OA mouse. An analysis of bioinformatics was performed on FKA and its potential role in OA. It was observed that FKA blocked interleukin (IL)-1β-induced expression of inflammatory factors, i.e., cyclooxygenase-2 (COX2) and inducible nitric oxide synthase (iNOS) in chondrocytes. In addition, FKA also downregulated the catabolic enzyme expression, i.e., aggrecanase-2 (ADAMTS5) and matrix metalloproteinases (MMPs), and helped in the upregulation of the anabolic protein expression, i.e., type II collagen (Col2), Aggrecan, and sry-box transcription factor 9 (SOX9). Moreover, FKA ameliorated IL-1β-triggered autophagy in chondrocytes, and it was observed that the FKA causes anti-inflammatory effects by the mitogen-activated protein kinase (MAPK) and phosphoinositide-3-kinase/Akt/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling pathways inhibition. The results of immunohistochemical analysis and microcomputed tomography from the in vivo OA mouse model confirmed the therapeutic effect of FKA. Finally, we assessed the anti-arthritic impacts of FKA by conducting in vivo and in vitro analyses. We concluded that FKA can be employed as a useful therapeutic agent for OA therapy, but the findings require needs further clinical investigation.

Analgesic effects and arthritic changes following intra-articular injection of diclofenac etalhyaluronate in a rat knee osteoarthritis model

Background

Diclofenac etalhyaluronate (DF-HA) is a recently developed analgesic conjugate of diclofenac and hyaluronic acid that has analgesic and anti-inflammatory effects on acute arthritis. In this study, we investigated its analgesic effect on osteoarthritis, using a rat model of monoiodoacetate (MIA).

Methods

We injected MIA into the right knees of eight 6-weeks-old male Sprague–Dawley rats. Four weeks later, rats were randomly injected with DF-HA or vehicle into the right knee. Seven weeks after the MIA injection, fluorogold (FG) and sterile saline were injected into the right knees of all the rats. We assessed hyperalgesia with weekly von Frey tests for 8 weeks after MIA administration. We took the right knee computed tomography (CT) as radiographical evaluation every 2 weeks. All rats were sacrificed 8 weeks after administration of MIA for histological evaluation of the right knee and immunohistochemical evaluation of the DRG and spinal cord. We also evaluated the number of FG-labeled calcitonin gene-related peptide (CGRP)-immunoreactive(ir) neurons in the dorsal root ganglion (DRG) and ionized calcium-binding adapter molecule 1 (Iba1)-ir microglia in the spinal cord.

Results

Administration of DF-HA significantly improved pain sensitivity and reduced CGRP and Iba1 expression in the DRG and spinal cord, respectively. However, computed tomography and histological evaluation of the right knee showed similar levels of joint deformity, despite DF-HA administration.

Conclusion

DF-HA exerted analgesic effects on osteoarthritic pain, but did not affect joint deformity.

Otto Aufranc Award: Identification of Key Molecular Players in the Progression of Hip Osteoarthritis Through Transcriptomes and Epigenetics

BACKGROUND

This study aimed: (1) to compare the transcriptome profile of articular cartilage in cam-FAI (early stage) to advanced OA secondary to cam-FAI (late stage) and (2) to investigate epigenetic changes through the expression of DNA methylation enzymes DNMT3B, DNMT1, and DNMT3A and peroxisome proliferator-activated receptor gamma (PPARγ) in human cartilage samples during the progression of hip OA.

METHODS

Full-thickness cartilage samples were collected from the anterolateral head-neck junction (impingement zone) of 22 patients (9 early-FAI and 13 late-FAI). RNA sequencing and in vitro cartilage cultures with histological analysis and immunohistochemistry staining for PPARγ and DNMT3B were performed. Target gene validation was confirmed with RT-PCR.

RESULTS

Fifty genes and 42 pathways were identified differentially between early and late-FAI (fold change <-1.5 or >1.5, P < .01). PPARγ and DNMT3B were gradually suppressed with disease progression. Contrarily, disease progression induced expression of DNMT1/3A.

CONCLUSION

By comparing comprehensive gene expression in early and late stage hip degeneration at the whole-genome level, distinct transcriptome profiles for early and late stage disease were identified along with key molecular contributors to the progression of hip OA. Preservation of endogenous PPARγ may have therapeutic potential to delay or prevent hip OA.

Evaluation of Different Intraarticular Injection Therapies with Gait Analysis in a Rat Osteoarthritis Model

OBJECTIVE

Osteoarthritis (OA) is a degenerative disease that causes serious damage to joints, especially in elderly patients. The aim of study was to demonstrate the effectiveness of intraarticular therapies that are currently used or recently popularized in the treatment of OA.

DESIGN

The baseline values were determined by walking the rats on the CatWalk system. Afterwards, a monosodium iodoacetate (MIA)-induced knee OA model was created with intraarticular MIA, and the rats were walked again on the CatWalk system and post-OA values were recorded. At this stage, the rats were divided into 4 groups, and intraarticular astaxanthin, intraarticular corticosteroid, intraarticular hyaluronic acid, and intraarticular astaxanthin + hyaluronic acid were applied to the groups, respectively. The rats were walked once more and posttreatment values were obtained. Nine different dynamic gait parameters were used in the comparison.

RESULTS

Significant changes were measured in 6 of the 9 dynamic gait parameters after the MIA-induced knee OA model. While the best improvement was observed in run duration (P = 0.0022), stride length (P < 0.0001), and swing speed (P = 0.0355) in the astaxanthin group, the results closest to basal values in paw print length (P < 0.0001), paw print width (P = 0.0101), and paw print area (P = 0.0277) were seen in the astaxanthin + hyaluronic acid group.

CONCLUSION

Astaxanthin gave better outcomes than corticosteroid and hyaluronic acid in both dynamic gait parameters and histological examinations. Intraarticular astaxanthin therapy can be a good alternative to corticosteroid and hyaluronic acid currently used in intraarticular therapy to treat OA.

Rhoifolin Ameliorates Osteoarthritis via Regulating Autophagy

Osteoarthritis (OA) is a common age-related joint disease. Its development has been generally thought to be associated with inflammation and autophagy. Rhoifolin (ROF), a flavanone extracted from Rhus succedanea, has exhibited prominent anti-oxidative and anti-inflammatory properties in several diseases. However the exact role of ROF in OA remains unclear. Here, we investigated the therapeutic effects as well as the underlying mechanism of ROF on rat OA. Our results indicated that ROF could significantly alleviate the IL-1β-induced inflammatory responses, cartilage degradation, and autophagy downregulation in rat chondrocytes. Moreover, administration of autophagy inhibitor 3-methyladenine (3-MA) could reverse the anti-inflammatory and anti-cartilage degradation effects of ROF. Furthermore, P38/JNK and PI3K/AKT/mTOR signal pathways were involved in the protective effects of ROF. In vivo, intra-articular injection of ROF could notably ameliorate the cartilage damage in rat OA model. In conclusion, our work elucidated that ROF ameliorated rat OA via regulating autophagy, indicating the potential role of ROF in OA therapy.

Mechanobiology of Cartilage Impact Via Real-Time Metabolic Imaging

Cartilage loading is important in both structural and biological contexts, with overloading known to cause osteoarthritis (OA). Cellular metabolism, which can be evaluated through the relative measures of glycolysis and oxidative phosphorylation, is important in disease processes across tissues. Details of structural damage coupled with cellular metabolism in cartilage have not been evaluated. Therefore, the aim of this study was to characterize the time- and location-dependent metabolic response to traumatic impact loading in articular cartilage. Cartilage samples from porcine femoral condyles underwent a single traumatic injury that created cracks in most samples. Before and up to 30 min after loading, samples underwent optical metabolic imaging. Optical metabolic imaging measures the fluorescent intensity of byproducts of the two metabolic pathways, flavin adenine dinucleotide for oxidative phosphorylation and nicotinamide adenine dinucleotide ± phosphate for glycolysis, as well as the redox ratio between them. Images were taken at varied distances from the center of the impact. Shortly after impact, fluorescence intensity in both channels decreased, while redox ratio was unchanged. The most dramatic metabolic response was measured closest to the impact center, with suppressed fluorescence in both channels relative to baseline. Redox ratio varied nonlinearly as a function of distance from the impact. Finally, both lower and higher magnitude loading reduced flavin adenine dinucleotide fluorescence, whereas reduced nicotinamide adenine dinucleotide ± phosphate fluorescence was associated only with low strain loads and high contact pressure loads, respectively. In conclusion, this study performed novel analysis of metabolic activity following induction of cartilage damage and demonstrated time-, distance-, and load-dependent response to traumatic impact loading.

Contribution of salidroside to the relieve of symptom and sign in the early acute stage of osteoarthritis in rat model

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Rhodiola has been used to treat cough, hemoptysis, fever, pain, bruise and other symptoms which are related to injury and inflammation over a thousand years in traditional Tibetan medicine. Salidroside (p-hydroxyphenethyl-β-D-glucoside) is one of the most potent bioactive ingredients of the genus Rhodiola.

AIM OF STUDY

The present study aimed to explore whether salidroside could alleviate the clinical symptom and sign in the early acute stage of osteoarthritis (OA) in monosodium iodoacetate (MIA) rat model, and its underlying mechanisms.

MATERIALS AND METHODS

Osteoarthritis (OA) was induced in rat knees by intra-articular injection of MIA; simultaneously salidroside was administered by intravenous injection. Pain behaviors were evaluated by knee-bend test, hind limb weight-bearing asymmetry and hind paw mechanical withdrawal threshold. The joint swelling was determined by the difference of knee joint diameter. Inflammatory exudates in synovial fluid were evaluated by leukocyte counting and protein content. Cytokines, chemokines, reactive oxygen species (ROS) and reactive nitrogen species (RNS) markers were determined by Enzyme-linked immunosorbent assay (ELISA) and colorimetric assay in synovial fluid. Pro-inflammatory gene expressions in synovial tissue were detected by quantitative real time RT-PCR (qRT-PCR). Nuclear factor kappa-B (NF-κB) DNA binding assay and western blot were used to determine NF-κB activation and ROS marker protein expression in synovial tissue. Glycosaminoglycan (GAG) content in the cartilage was measured by dimethylmethylene blue method. Hematoxylin and eosin (H&E), Safranin O-fast green and a modified Mankin grading system were used to evaluate the histology of articular cartilage.

RESULTS

Salidroside could alleviate pain and joint swelling in the early acute stage of OA in rat model, reduced the number of leukocytes, total protein content, proinflammatory mediators and ROS/RNS markers in synovial fluid, down regulated the expression of proinflammatory genes in synovium, inhibited the activation of NF- κ B and oxidative stress response in synovium, promoted the synthesis of cartilage GAG, prevented the loss of proteoglycan and chondrocyte degeneration.

CONCLUSIONS

Salidroside effectively alleviates acute symptom and sign of OA in rat model by its anti-inflammatory and antioxidant affects to inhibit synovial inflammation, which provides a new strategy to prevent the onset and progression of OA.

Astilbin influences the progression of osteoarthritis in rats by down-regulation of PGE-2 expression via the NF-κB pathway

Background

Osteoarthritis (OA) is the most common joint disease, affecting most middle-aged and elderly people. Astilin (AST) is the main active ingredient isolated from the traditional Chinese medicine Astilbe chinensis and has anti-inflammatory and anti-arthritis effects. The purpose of this study was to investigate the effect and mechanism of AST on OA in rats mediated by papain.

Methods

In this study, in vivo experiments were conducted to investigate the protective effect and potential mechanism of Astilbin (AST) when it inhibited the development of osteoarthritis (OA).

Results

A rat model of OA is constructed. Through HE staining, it is found that AST can protect the articular surface and reduce damage. The results of immunohistochemical staining also prove that AST can inhibit the expression of prostaglandin E2 (PGE2) and has an excellent inhibitory effect on inflammatory factors. It is found that AST can significantly inhibit the protein expression of interleukin 1 beta (IL-1β), TNF-α, and NF-κB. Polymerase Chain Reaction (PCR) assay shows that the mRNA of IL-1β, TNF-α, and NF-κB is down-regulated, which also proves that the protective mechanism of AST is related to the NF-κB pathway.

Conclusions

In general, this study proves that AST can be a potential therapy for degenerative joint diseases, including OA.

Proteoglycan synthesis rate as a novel method to measure blood-induced cartilage degeneration in non-haemophilic and haemophilic rats

INTRODUCTION

Haemophilic animal models are used to study blood-induced cartilage damage, but quantitative and sensitive outcome measures are needed.

AIM

To develop a novel quantitative method for detecting early cartilage degeneration in a haemophilic rat model of blood-induced joint damage.

METHODS

The ³⁵ Sulphate incorporation (³⁵ SO₄ ^2- assay) was applied to tibial and patellar cartilage of wild-type rats to quantify baseline proteoglycan synthesis and to evaluate the effect of 4-day blood exposure in vitro. Next, haemarthrosis was induced in 39 FVIII-deficient rats and characterized by changes in knee joint diameter and development of bone pathology (using micro-CT). Four- and 16-day posthaemarthrosis proteoglycan synthesis rate (PSR) was assessed using the ³⁵ SO₄ ^2- assay, with the contralateral knee as control.

RESULTS

In vitro, a decrease in PSR in tibial and patellar cartilage was demonstrated following blood exposure. In vivo, joint diameter and development of bone pathology confirmed successful induction of haemarthrosis. In the blood-exposed knee, tibial and patellar PSR was inhibited 4 and 16 days after induced haemarthrosis. Interestingly, at day 16 the proteoglycan synthesis in the contralateral knee was also inhibited to an extent correlating with that of the blood-exposed knee.

CONCLUSION

For the first time, early changes in cartilage matrix synthesis upon blood exposure were quantified with the ³⁵ SO₄ ^2- assay in a haemophilic rat model, establishing this assay as a novel method to study blood-induced cartilage damage.

Small extracellular vesicles from human adipose-derived stem cells attenuate cartilage degeneration

Osteoarthritis (OA) is a chronic degenerative disease of articular cartilage that is the most common joint disease worldwide. Mesenchymal stem cells (MSCs) have been the most extensively explored for the treatment of OA. Recently, it has been demonstrated that MSC-derived extracellular vesicles (EVs) may contribute to the potential mechanisms of MSC-based therapies. In this study, we investigated the therapeutic potential of human adipose-derived stem cells EVs (hASC-EVs) in alleviating OA, along with the mechanism. EVs were isolated from the culture supernatants of hASCs by a multi-filtration system based on the tangential flow filtration (TFF) system. The isolated EVs were characterised using dynamic light scattering (DLS), transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA) and flow cytometry analysis. The hASC-EVs not only promoted the proliferation and migration of human OA chondrocytes, but also maintained the chondrocyte matrix by increasing type Ⅱ collagen synthesis and decreasing MMP-1, MMP-3, MMP-13 and ADAMTS-5 expression in the presence of IL-1β in vitro. Intra-articular injection of hASC-EVs significantly attenuated OA progression and protected cartilage from degeneration in both the monosodium iodoacetate (MIA) rat and the surgical destabilisation of the medial meniscus (DMM) mouse models. In addition, administration of hASC-EVs inhibited the infiltration of M1 macrophages into the synovium. Overall results suggest that the hASC-EVs should be considered as a potential therapeutic approach in the treatment of OA.

COL2A1 and Caspase-3 as Promising Biomarkers for Osteoarthritis Prognosis in an Equus asinus Model

Osteoarthritis (OA) is one of the most degenerative joint diseases in both human and veterinary medicine. The objective of the present study was the early diagnosis of OA in donkeys using a reliable grading of the disease based on clinical, chemical, and molecular alterations. OA was induced by intra-articular injection of 25 mg monoiodoacetate (MIA) as a single dose into the left radiocarpal joint of nine donkeys. Animals were clinically evaluated through the assessment of lameness score, radiographic, and ultrasonographic findings for seven months. Synovial fluid and cartilage samples were collected from both normal and diseased joints for the assessment of matrix metalloproteinases (MMPs) activity, COL2A1 protein expression level, and histopathological and immunohistochemical analysis of Caspase-3. Animals showed the highest lameness score post-induction after one week then decreased gradually with the progression of radiographical and ultrasonographic changes. MMP activity and COL2A1 and Caspase-3 expression increased, accompanied by articular cartilage degeneration and loss of proteoglycan. OA was successfully graded in Egyptian donkeys, with the promising use of COL2A1and Caspase-3 for prognosis. However, MMPs failed to discriminate between early and late grades of OA.

Pharmacological and biochemical properties of Zingiber zerumbet (L.) Roscoe ex Sm. and its therapeutic efficacy on osteoarthritis of knee

Osteoarthritis (OA) as the most frequent form of knee arthritis is one of the most annoying complications amongst old peoples. There are different pharmacological and non-pharmacological remedies which could be applied for treatment of knee OA. It's while, significant side effects mostly in patients who are older are the dangerous limiting factors. Integrative, supplementary, traditional remedies have been applied from long time ago in treatment of such chronic diseases like OA. Various topical and oral remedies have been presented in treatment of OA worldwide. In spite of the fact there are multiple remedies for reduction symptoms of patients who suffer from disorders and related inabilities which could enhance their life quality. Remedies which have been applied for a long time for treatment of OA have newly discovered to induce injury to some patients. On the other side, additional knowledge about alternative and supplementary remedies is a main way for enhancing health of patients who suffer from OA disorders. Zingiber zerumbet (Z. zerumbeton) is a kind of herb of the ginger family and is a natural compound with various biomedical characteristics like anti-proliferative, anti-inflammatory, and antioxidant effect. However, Z. zerumbet could be applied for reduction of OA symptoms because of its circulatory stimulant and anti-inflammatory effects. Anyway, up to now there is not any methodical literature review for evaluating the Z. zerumbet clinical effectiveness productiveness in treatment of OA. The main aim of the current study is to review scientific resources around therapeutic effectiveness of Zingiber zerumbet in treatment of adverse symptoms of OA disorder.

PPARγ preservation via promoter demethylation alleviates osteoarthritis in mice

OBJECTIVES

Osteoarthritis (OA) is the most common degenerative joint disease in aged population and its development is significantly influenced by aberrant epigenetic modifications of numerous OA susceptible genes; however, the precise mechanisms that DNA methylation alterations affect OA pathogenesis remain undefined. This study investigates the critical role of epigenetic PPARγ (peroxisome proliferator-activated receptor-gamma) suppression in OA development.

METHODS

Articular cartilage expressions of PPARγ and bioactive DNA methyltransferases (DNMTs) from OA patients and mice incurred by DMM (destabilisation of medial meniscus) were examined. DNA methylation status of both human and mouse PPARγ promoters were assessed by methylated specific PCR and/or bisulfite-sequencing PCR. OA protections by a pharmacological DNA demethylating agent 5Aza (5-Aza-2'-deoxycytidine) were compared between wild type and PPARγ knockout mice.

RESULTS

Articular cartilages from both OA patients and DMM mice display substantial PPARγ suppressions likely due to aberrant elevations of DNMT1 and DNMT3a and consequential PPARγ promoter hypermethylation. 5Aza known to inhibit both DNMT1 and DNMT3a reversed the PPARγ promoter hypermethylation, recovered the PPARγ loss and effectively attenuated the cartilage damage in OA mice. 5Aza also inhibited the OA-associated excessive inflammatory cytokines and deficit anti-oxidant enzymes, which were blocked by a specific PPARγ inhibitor in cultured chondrocytes. Further, 5Aza-confered protections against the cartilage damage and the associated abnormalities of OA-susceptible factors were significantly abrogated in PPARγ knockout mice.

CONCLUSION

Epigenetic PPARγ suppression plays a key role in OA development and PPARγ preservation via promoter demethylation possesses promising therapeutic potentials in clinical treatment of OA and the related joint diseases.

MSC exosomes alleviate temporomandibular joint osteoarthritis by attenuating inflammation and restoring matrix homeostasis

The efficacy of mesenchymal stem cell (MSC) therapies is increasingly attributed to paracrine secretion, particularly exosomes. In this study, we investigated the role of MSC exosomes in the regulation of inflammatory response, nociceptive behaviour, and condylar cartilage and subchondral bone healing in an immunocompetent rat model of temporomandibular joint osteoarthritis (TMJ-OA). We observed that exosome-mediated repair of osteoarthritic TMJs was characterized by early suppression of pain and degeneration with reduced inflammation, followed by sustained proliferation and gradual improvements in matrix expression and subchondral bone architecture, leading to overall joint restoration and regeneration. Using chondrocyte cultures, we could attribute some of the cellular activities during exosome-mediated joint repair to adenosine activation of AKT, ERK and AMPK signalling. Specifically, MSC exosomes enhanced s-GAG synthesis impeded by IL-1β, and suppressed IL-1β-induced nitric oxide and MMP13 production. These effects were partially abrogated by inhibitors of adenosine receptor activation, AKT, ERK and AMPK phosphorylation. Together, our observations suggest that MSC exosomes promote TMJ repair and regeneration in OA through a well-orchestrated mechanism of action that involved multiple cellular processes to restore the matrix and overall joint homeostasis. This study demonstrates the translational potential of a cell-free ready-to-use exosome-based therapeutic for treating TMJ pain and degeneration.

Physical Activity Is Related with Cartilage Quality in Women with Knee Osteoarthritis

PURPOSE

To study the relationship between 12-month leisure-time physical activity (LTPA) level and changes in estimated biochemical composition of tibiofemoral cartilage in postmenopausal women with mild knee osteoarthritis (OA).

METHODS

Originally, 87 volunteer postmenopausal women, age 60 to 68 yr, with mild knee OA (Kellgren Lawrence I/II and knee pain) participated in a randomized controlled, 4-month aquatic training trial (RCT), after which 76 completed the 12-month postintervention follow-up period. Self-reported LTPA was collected along the 12-month period using a diary from which MET task hours per month were calculated. Participants were divided into MET task hour tertiles: 1, lowest (n = 25); 2 = middle (n = 25) and 3 = highest (n = 26). The biochemical composition of the cartilage was estimated using transverse relaxation time (T2) mapping sensitive to the properties of the collagen network and delayed gadolinium-enhanced magnetic resonance imaging of the cartilage (dGEMRIC index) sensitive to the cartilage glycosaminoglycan content. Secondary outcomes were cardiorespiratory fitness, isometric knee extension and flexion force, and the knee injury and OA outcome questionnaire.

RESULTS

During the 12-month follow-up period, there was a significant linear relationship between higher LTPA level and increased dGEMRIC index changes in the posterior region of interest (ROI) of the lateral (P = 0.003 for linearity) and medial (P = 0.006) femoral cartilage. Furthermore, these changes were seen in the posterior lateral femoral cartilage superficial (P = 0.004) and deep (P = 0.007) ROI and in the posterior medial superficial ROI (P < 0.001). There was no linear relationship between LTPA level and other measured variables.

CONCLUSIONS

These results suggest that higher LTPA level is related to regional increases in estimated glycosaminoglycan content of tibiofemoral cartilage in postmenopausal women with mild knee OA as measured with dGEMRIC index during a 12-month period.

Meloxicam ameliorates the cartilage and subchondral bone deterioration in monoiodoacetate-induced rat osteoarthritis

OBJECTIVE

This study aimed to quantify the cartilage- and subchondral bone-related effects of low-dose and high-dose meloxicam treatment in the late phase of mono-iodoacetate-induced osteoarthritis of the stifle.

METHODS

Thirty-four male Wistar rats received intra-articular injection of mono-iodoacetate to trigger osteoarthritis; 10 control animals (Grp Co) received saline. The mono-iodoacetate-injected rats were assigned to three groups and treated from week 4 to the end of week 7 with placebo (Grp P, n = 11), low-dose (GrpM Lo, 0.2 mg/kg, n = 12) or high-dose (GrpM Hi, 1 mg/kg, n = 11) meloxicam. After a period of 4 additional weeks (end of week 11) the animals were sacrificed, and the stifle joints were examined histologically and immunohistochemically for cyclooxygenase 2, in conformity with recommendations of the Osteoarthritis Research Society International. Serum cytokines IL-6, TNFα and IL-10 were measured at the end of weeks 3, 7, and 11.

RESULTS

Compared with saline-treated controls, animals treated with mono-iodoacetate developed various degrees of osteoarthritis. The cartilage degeneration score and the total cartilage degeneration width were significantly lower in both the low-dose (p = 0.012 and p = 0.014) and high-dose (p = 0.003 and p = 0.006) meloxicam-treated groups than in the placebo group. In the subchondral bone, only high-dose meloxicam exerted a significant protective effect (p = 0.011). Low-grade Cox-2 expression observed in placebo-treated animals was abolished in both meloxicam groups. Increase with borderline significance of TNFα in GrpP from week 3 to week 7 (p = 0.049) and reduction of IL-6 in GrpM Lo from week 3 to week 11 (p = 0.044) were observed.

CONCLUSION

In this rat model of osteoarthritis, both low-dose and high-dose meloxicam had a chondroprotective effect, and the high dose also protected against subchondral bone lesions. The results suggest a superior protection of the high-dose meloxicam arresting the low-grade inflammatory pathway accompanied by chronic cartilage deterioration.

A novel rabbit model of early osteoarthritis exhibits gradual cartilage degeneration after medial collateral ligament transection outside the joint capsule

Though many surgical animal models have been used to induce osteoarthritis (OA) of the knee joint, they always open the capsule of the joint. Any surgical procedures that incises the capsule may cause inflammation, pain, and possibly altered gait. One common disadvantage of these surgically induced animal models is that they may affect the initial structures and synovial fluid in joint. These animal models may not be suitable for research into synovial fluid changes during early OA. This study aimed to create an animal model of early OA by resecting the medial collateral ligament (MCL) outside of the capsule. At 1, 2, 3, 4, 5 and 6 weeks after surgery, eight knees from each group were harvested. The joint gap was measured on posteroanterior radiographs after MCL-transection (MCLT). Gross examination and histological analysis were performed to evaluate cartilage damage to the medial femoral condyles, and knee joints were scanned using a Micro-CT system. The MCLT group experienced early stage OA from 3 to 6 weeks according to the histological scores. IL-6, MMP-1 and MMP-13 content in the synovial fluid were higher after MCLT than anterior cruciate ligament transection (ACLT) at 1 and 2 weeks.

Rutin protects rat articular chondrocytes against oxidative stress induced by hydrogen peroxide through SIRT1 activation

The progressive degeneration and ossification of articular chondrocytes are main symptoms in the pathogenesis of osteoarthritis (OA). Several flavonoids may provide an adjunctive alternative for the management of moderate OA in humans. Rutin, a natural flavone derivative (quercetin-3-rhamnosylglucoside), is well known for its potent anti-inflammatory and anti-oxidant properties against oxidative stress. However, the protective function of rutin related to OA, which is characterized by deterioration of articular cartilage, remains unclear. The present study investigated the protective effects of rutin, an activator of silent information regulator 1 (SIRT1), involved in the inhibition of NF-κB/MAPK signaling pathway in hydrogen peroxide (H2O2)-induced oxidative stress in rat chondrocytes. SIRT1 activation by rutin attenuated levels of inflammatory cytokines and NF-κB/MAPK signaling, whereas the inhibition of SIRT1 by sirtinol counteracted the beneficial effects of rutin in H2O2-treated chondrocytes. The findings of these studies suggested the potential involvement of SIRT1 in the pathogenesis of OA, and indicated that rutin is a possible therapeutic option for OA.

Effects of intra-articular SHINBARO treatment on monosodium iodoacetate-induced osteoarthritis in rats

BACKGROUND

SHINBARO is a refined herbal formulation used to treat inflamed lesions and bone diseases. This study aimed to investigate the anti-osteoarthritic activities of intra-articular administration of SHINBARO and determine its underlying molecular mechanism in a monosodium iodoacetate (MIA)-induced osteoarthritis rat model.

METHODS

Male Sprague-Dawley rats received a single intra-articular injection of MIA into the infrapatellar ligament of the right knee. Subsequently, the rats were treated with normal saline, SHINBARO, and diclofenac once daily for 21 days. Rats treated with normal saline, but not MIA, comprised the control group. Histological changes in the femur of the MIA-induced osteoarthritis rat model were observed by micro-computed tomography scanning and staining with hematoxylin and eosin, and safranin-O fast green. Serum levels of PGE2 and anti-type II collagen antibodies in the MIA-induced osteoarthritis rat model were measured using commercial kits. Protein levels of inflammatory enzymes (iNOS, COX-2), pro-inflammatory cytokines (TNF-α, IL-1β), and inflammatory mediators (NF-κB, IκB) in cartilaginous tissues were determined by western blot analysis.

RESULTS

Intra-articular administration of SHINBARO (IAS) at 20 mg/kg remarkably restrained the decrease in bone volume/total volume, being 28 % (P = 0.0001) higher than that in the vehicle-treated MIA group. IAS (2, 10, and 20 mg/kg) treatment significantly recovered the mean number of objects values with increased percentage changes of 13.5 % (P = 0.147), 27.5 % (P = 0.028), and 44.5 % (P = 0.031), respectively, compared with the vehicle-treated MIA group. The serum level of PGE2 in the IAS group at 20 mg/kg was markedly inhibited by 60.6 % (P = 0.0007) compared with the vehicle-treated MIA group, and the anti-collagen type II antibody level in the IAS group was reduced in a dose-dependent manner. IAS (20 mg/kg) effectively suppressed the induction of inflammation-mediated enzymes (iNOS and COX-2) and pro-inflammatory cytokines (TNF-α and IL-1β). IAS treatment also downregulated the NF-κB level and increased the IκB-α level in the MIA- induced osteoarthritis rat model.

CONCLUSION

SHINBARO inhibited PGE2 and anti-type II collagen antibody production and modulated the balance of inflammatory enzymes, mediators, and cytokines in the MIA-induced osteoarthritis rat model.

Regional dGEMRIC analysis in patients at risk of osteoarthritis provides additional information about activity related changes in cartilage structure

BACKGROUND

Previously, a positive effect of exercise on cartilage structure was indicated with delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC). However, in that study only one full-thickness region of interest (ROI) in the medial femoral condyle was analyzed.

PURPOSE

To improve the knowledge about exercise effects on cartilage structure by re-analyzing previous images with regional dGEMRIC analysis.

MATERIAL AND METHODS

Thirty patients (age range, 38-50 years) with a previous medial meniscus resection were divided into three groups according to self-reported change in physical activity (PA) level in a 4-month exercise intervention study: Group I (n = 11), increased PA level; Group II (n = 13), no change in PA level; and Group III (n = 6), reduced PA level. dGEMRIC index was analyzed at inclusion and after 4 months. Anterior (less load) and posterior (more load) ROIs of medial and lateral femoral condyles were analyzed, as well as superficial and deep cartilage regions.

RESULTS

Group I increased the dGEMRIC index in the posterior cartilage (P = 0.004). The increase was larger in the lateral (P = 0.005) than the medial compartment in both superficial and deep cartilage regions. The dGEMRIC index did not change in Group II. In Group III, the dGEMRIC index decreased in the medial posterior cartilage (P = 0.03).

CONCLUSION

In patients with a previous medial meniscectomy, the beneficial effect of exercise varies between different locations within the joint, the largest improvement being observed in lateral posterior cartilage, i.e. the load-bearing cartilage in the compartment without a meniscus lesion. The effects of exercise do not seem to vary with cartilage depth.

Safety and biodistribution assessment of sc-rAAV2.5IL-1Ra administered via intra-articular injection in a mono-iodoacetate-induced osteoarthritis rat model

Interleukin-1 (IL-1) plays an important role in the pathophysiology of osteoarthritis (OA), and gene transfer of IL-1 receptor antagonist (IL-1Ra) holds promise for OA treatment. A preclinical safety and biodistribution study evaluated a self-complementary adeno-associated viral vector carrying rat IL-1Ra transgene (sc-rAAV2.5rIL-1Ra) at 5 × 10⁸, 5 × 10⁹, or 5 × 10¹⁰ vg/knee, or human IL-1Ra transgene (sc-rAAV2.5hIL-1Ra) at 5 × 10¹⁰ vg/knee, in Wistar rats with mono-iodoacetate (MIA)–induced OA at days 7, 26, 91, 180, and 364 following intra-articular injection. The MIA-induced OA lesions were consistent with the published data on this model. The vector genomes persisted in the injected knees for up to a year with only limited vector leakage to systemic circulation and uptake in tissues outside the knee. Low levels of IL-1Ra expression and mitigation of OA lesions were observed in the vector-injected knees, albeit inconsistently. Neutralizing antibodies against the vector capsid developed in a dose-dependent manner, but only the human vector induced a small splenic T-cell immune response to the vector capsid. No local or systemic toxicity attributable to vector administration was identified in the rats as indicated by clinical signs, body weight, feed consumption, clinical pathology, and gross and microscopic pathology through day 364. Taken together, the gene therapy vector demonstrated a favorable safety profile.

Monosodium iodoacetate-induced inflammation and joint pain are reduced in TRPA1 deficient mice--potential role of TRPA1 in osteoarthritis

OBJECTIVES

Intra-articularly injected monosodium iodoacetate (MIA) induces joint pathology mimicking osteoarthritis (OA) and it is a widely used experimental model of OA. MIA induces acute inflammation, cartilage degradation and joint pain. Transient Receptor Potential Ankyrin 1 (TRPA1) is an ion channel known to mediate nociception and neurogenic inflammation. Here, we tested the hypothesis that TRPA1 would be involved in the development of MIA-induced acute inflammation, cartilage changes and joint pain.

METHODS

The effects of pharmacological blockade (by TCS 5861528) and genetic depletion of TRPA1 were studied in MIA-induced acute paw inflammation. Cartilage changes (histological scoring) and joint pain (weight-bearing test) in MIA-induced experimental OA were compared between wild type and TRPA1 deficient mice. The effects of MIA were also studied in primary human OA chondrocytes and in mouse cartilage.

RESULTS

MIA evoked acute inflammation, degenerative cartilage changes and joint pain in wild type mice. Interestingly, these responses were attenuated in TRPA1 deficient animals. MIA-induced paw inflammation was associated with increased tissue levels of substance P; and the inflammatory edema was reduced by pretreatment with catalase, with the TRPA1 antagonist TCS 5861528 and with the neurokinin 1 receptor antagonist L703,606. In chondrocytes, MIA enhanced interleukin-1 induced cyclooxygenase-2 (COX-2) expression, an effect that was blunted by pharmacological inhibition and genetic depletion of TRPA1.

CONCLUSIONS

TRPA1 was found to mediate acute inflammation and the development of degenerative cartilage changes and joint pain in MIA-induced experimental OA in the mouse. The results reveal TRPA1 as a potential mediator and drug target in OA.

Silencing of miR-101 Prevents Cartilage Degradation by Regulating Extracellular Matrix-related Genes in a Rat Model of Osteoarthritis

Osteoarthritis (OA) is a common, degenerative joint disease characterized by articular cartilage degradation. Currently, clinical trials based on microRNA therapy have been performed to treat various diseases. However, no treatment has been found for arthritis. This study investigated the functions of miR-101 in cartilage degradation in vivo and evaluated the feasibility of using miR-101 as a therapeutic agent for OA. Mono-iodoacetate-induced arthritis (MIA) rats were used as an animal model of OA. miR-101 mimic or miR-101 inhibitor was injected into the rats' knees to evaluate its effects on cartilage degradation. Cartilage degradation aggravated at 14 days after the injection of miR-101 mimic. By contrast, miR-101 silencing reduced cartilage degradation. Moreover, the administration of miR-101 mimic is sufficient to cause cartilage degradation in the normal cartilage of rats. By contrast, miR-101 inhibitor could prevent this change. Microarray and qPCR were used to investigate the different expressed genes after injecting miR-101 mimic and miR-101 inhibitor in the rats' articular cartilage. Several cartilage degradation-related genes were selected and validated to function in cartilage degradation with miR-101. Our results demonstrated the therapeutic effect of miR-101 inhibition on cartilage degradation in MIA rats by regulating several cartilage degradation-related genes.

Sulforaphane-PLGA microspheres for the intra-articular treatment of osteoarthritis

Sulforaphane (SFN) is a member of the isothiocyanate family that has anti-inflammatory action as well as anti-carcinogenic properties. The authors have devised an intra-articular injectable SFN-PLGA microsphere system that can be used for treating osteoarthritis (OA). The purpose of this study was to evaluate the in vitro and in vivo efficacy of the SFN-PLGA microsphere system. Articular chondrocytes were obtained from knee OA patients and were cultured in monolayers. The optimal concentration of SFN was obtained and the dose of SFN-PLGA microspheres was determined based on the concentration. The in vitro anti-inflammatory effect on markers such as cyclooxygenase (COX)-2, a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)-5, and matrix metalloproteinase (MMP)-2 was assessed by real-time PCR and Western blotting. The in vivo therapeutic effect of SFN-PLGA microspheres was investigated using surgically-induced rat OA model. Treatment with SFN-PLGA microspheres inhibited the mRNA and protein expression of COX-2, ADAMTS-5 and MMP-2 induced by LPS in articular chondrocytes. Intraarticular SFN-PLGA microspheres delayed the progression of surgically-induced osteoarthritis in rats. In conclusion, SFN-PLGA microspheres can be a useful injectable delivery system for treating osteoarthritis.

Expression of peroxisome proliferator-activated receptors α, β, γ, and H- and L-prostaglandin D synthase during osteoarthritis in the spontaneous hartley guinea pig and experimental dog models

OBJECTIVE

To investigate the expression of peroxisome proliferator-activated receptors (PPAR) α, β, and γ, and hematopoietic and lipocalin-type prostaglandin D synthase (H- and L-PGDS) over the course of osteoarthritis (OA) in the spontaneous Hartley guinea pig and the anterior cruciate ligament transection dog models.

METHODS

Guinea pigs were sacrificed at 2 (control group), 4, 8, and 12 months of age (n = 5 per group). Non-operated (control) and operated dogs were sacrificed at 4, 8, and 12 weeks postsurgery. Cartilage was evaluated histologically using the Osteoarthritis Research Society International (OARSI) guidelines. The expression of PPAR-α, β, γ, and H- and L-PGDS was evaluated by real-time PCR and immunohistochemistry. The nonparametric Spearman test was used for correlation analysis.

RESULTS

PPAR-α, β, and γ were detected in medial tibial plateau from control animals in both the spontaneous and surgical models. Levels of PPAR-α and β did not change over the course of OA, whereas PPAR-γ levels decreased during progression of disease. We also observed that the expression of H-PGDS remained unchanged, whereas L-PGDS increased over the course of OA. PPAR-γ levels correlated negatively, whereas L-PGDS levels correlated positively, with the histological score of OA.

CONCLUSION

The level of PPAR-γ decreased, whereas level of L-PGDS increased during the progression of OA. These data suggest that reduced expression of PPAR-γ may contribute to the pathogenesis of OA, whereas enhanced expression of L-PGDS may be part of a reparative process.

Preventive administration of juanbi capsules for knee osteoarthritis: effects on serum MMP-2 and MMP-9 levels and cartilage repair

OBJECTIVE

To explore the mechanism of action of Juanbi Capsules, a Chinese medicine for invigorating the kidney and replenishing qi, in preventing osteoarthritis of the knee in rabbits.

METHODS

Seventy-two 4-month-old, Japanese long-eared white rabbits were randomly divided into 6 groups: control (group A), model (group B), Chinese drug; high-dose (group C), Chinese drug; mid-dose (group D), Chinese drug; low-dose (group E), and drug control (group F). With the exception of the rabbits in group A, each rabbit was subjected to plaster cast fixation for 6 weeks to induce osteoarthritis. In addition, rabbits were administrated with an intragastric injection of the Chinese drug (groups C, D and E) or an aminoglucose hydrochloride capsule (group F) for 4 weeks. Blood was drawn from the central ear artery for serum MMP-2 and MMP-9 concentrations, and the knee joint cartilage was harvested for gross observation and light microscopy.

RESULTS

There were significant differences in serum MMP-2 and MMP-9 concentrations between group B and groups C, D and E (P < 0.05), with no significant differences between groups D and F. Histological results showed various changes in tissue staining with treatment, with osteophyte and bone cyst formation, and superficial erosion in the articular surface of the cartilage; in some cases, the defect reached the mid-layer of the cartilage, and these changes were lower than those in the model group.

CONCLUSION

Juanbi Capsules assist in preventing osteoarthritis in the rabbit, possibly by decreasing serum MMP-2 and MMP-9 levels.

Grape seed proanthocyanidin extract ameliorates monosodium iodoacetate-induced osteoarthritis

Osteoarthritis (OA) is an age-related joint disease that is characterized by degeneration of articular cartilage and chronic pain. Oxidative stress is considered one of the pathophysiological factors in the progression of OA. We investigated the effects of grape seed proanthocyanidin extract (GSPE), which is an antioxidant, on monosodium iodoacetate (MIA)-induced arthritis of the knee joint of rat, which is an animal model of human OA. GSPE (100 mg/kg or 300 mg/kg) or saline was given orally three times per week for 4 weeks after the MIA injection. Pain was measured using the paw withdrawal latency (PWL), the paw withdrawal threshold (PWT) and the hind limb weight bearing ability. Joint damage was assessed using histological and microscopic analysis and microcomputerized tomography. Matrix metalloproteinase-13 (MMP13) and nitrotyrosine were detected using immunohistochemistry. Administration of GSPE to the MIA-treated rats significantly increased the PWL and PWT and this resulted in recovery of hind paw weight distribution (P < 0.05). GSPE reduced the loss of chondrocytes and proteoglycan, the production of MMP13, nitrotyrosine and IL-1β and the formation of osteophytes, and it reduced the number of subchondral bone fractures in the MIA-treated rats. These results indicate that GSPE is antinociceptive and it is protective against joint damage in the MIA-treated rat model of OA. GSPE could open up novel avenues for the treatment of OA.

Effect of GCSB-5, a Herbal Formulation, on Monosodium Iodoacetate-Induced Osteoarthritis in Rats

Therapeutic effects of GCSB-5 on osteoarthritis were measured by the amount of glycosaminoglycan in rabbit articular cartilage explants in vitro, in experimental osteoarthritis induced by intra-articular injection of monoiodoacetate in rats in vivo. GCSB-5 was orally administered for 28 days. In vitro, GCSB-5 inhibited proteoglycan degradation. GCSB-5 significantly suppressed the histological changes in monoiodoacetate-induced osteoarthritis. Matrix metalloproteinase (MMP) activity, as well as, the levels of serum tumor necrosis factor-α, cyclooxygenase-2, inducible nitric oxide synthase protein, and mRNA expressions were attenuated by GCSB-5, whereas the level of interleukin-10 was potentiated. By GCSB-5, the level of nuclear factor-κB p65 protein expression was significantly attenuated but, on the other hand, the level of inhibitor of κB-α protein expression was increased. These results indicate that GCSB-5 is a potential therapeutic agent for the protection of articular cartilage against progression of osteoarthritis through inhibition of MMPs activity, inflammatory mediators, and NF-κB activation.

Combined prescription (OAH19T) of Aralia cordata Thunb and Cimicifuga heracleifolia Komar and its major compounds inhibit matrix proteinases and vascular endothelial growth factor through the regulation of mitogen-activated protein kinase pathway

ETHNOPHARMACOLOGICAL RELEVANCE

OAH19T, a new herbal extract from a mixture of Aralia cordata Thunb and Cimicifuga heracleifolia, is traditionally used for the treatment of arthritis in far East Asia. To investigate the chondroprotective effects of OAH19T on osteoarthritis was examined and compared with its major compounds pimaradienoic acid (PA) and ferulic acid (FA) of human osteoarthritis (OA) chondrocytes.

MATERIALS AND METHODS

Chondrocytes, alone or in the presence of IL-1β, were cultured with or without OAH19T, PA or FA (10, 20, 40 μg/ml). The release of sulfated glycosaminoglycan (GAG) was measured by colorimetric assay using 1,9-dimethylmethylene blue (DMB) reagent from the cultured media. The level of aggrecanases and VEGF was measured by reverse transcription polymerase chain reaction (RT-PCR). The expression of MMP-1 and MMP-3 analyzed by real time RT-PCR and enzyme-linked immunosorbent assay (ELISA). The phosphorylation of mitogen-activated protein kinases was performed by immunoblotting in OA chondrocytes. The proliferation was examined by the BrdU assay.

RESULTS

OAH19T markedly inhibited the release of proteoglycan and the degradation of aggrecan, in a dose-dependent manner in OA chondrocytes. OAH19T also inhibited the level of aggrecanase-1, aggrecanase-2, MMP-1, MMP-3, and VEGF in OA chondrocytes. PA and FA also inhibited the level of aggrecanase-2, MMP-3 and VEGF, while did not significantly affect the levels of aggrecanase-1, MMP-3 in OA chondrocytes. OAH19T exhibited the down-regulation of p38 MAP kinase unlike PA and FA in OA chondrocytes without cytotoxicity. In addition, p38 inhibitor SB203580 abolished the antiproliferative activity and proteoglycan degradation by OAH19T, while had no effect by PA or FA.

CONCLUSION

OAH19T have shown the chondroprotective effect by inhibiting cell proliferation, expression of cartilage-specific matrix proteinases and release of VEGF, but bigger than PA or FA, through down-regulation of p38 MAP kinase in human OA chondocyte. These results provide pharmacological basis for use in treatment of OA.

Contribution of H3K4 methylation by SET-1A to interleukin-1-induced cyclooxygenase 2 and inducible nitric oxide synthase expression in human osteoarthritis chondrocytes

OBJECTIVE

To investigate the role of histone H3 lysine 4 (H3K4) methylation in interleukin-1β (IL-1β)-induced cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS) expression in human osteoarthritic (OA) chondrocytes.

METHODS

Chondrocytes were stimulated with IL-1, and the expression of iNOS and COX-2 messenger RNA and proteins was evaluated by real-time reverse transcriptase-polymerase chain reaction analysis and Western blotting, respectively. H3K4 methylation and the recruitment of the histone methyltransferases SET-1A and MLL-1 to the iNOS and COX-2 promoters were evaluated using chromatin immunoprecipitation assays. The role of SET-1A was further evaluated using the methyltransferase inhibitor 5'-deoxy-5'-(methylthio)adenosine (MTA) and gene silencing experiments. SET-1A level in cartilage was determined using immunohistochemistry.

RESULTS

The induction of iNOS and COX-2 expression by IL-1 was associated with H3K4 di- and trimethylation at the iNOS and COX-2 promoters. These changes were temporally correlated with the recruitment of the histone methyltransferase SET-1A, suggesting an implication of SET-1A in these modifications. Treatment with MTA inhibited IL-1-induced H3K4 methylation as well as IL-1-induced iNOS and COX-2 expression. Similarly, SET-1A gene silencing with small interfering RNA prevented IL-1-induced H3K4 methylation at the iNOS and COX-2 promoters as well as iNOS and COX-2 expression. Finally, we showed that the level of SET-1A expression was elevated in OA cartilage as compared with normal cartilage.

CONCLUSION

These results indicate that H3K4 methylation by SET-1A contributes to IL-1-induced iNOS and COX-2 expression and suggest that this pathway could be a potential target for pharmacologic intervention in the treatment of OA and possibly other arthritic diseases.

Developmental mechanisms in articular cartilage degradation in osteoarthritis

Osteoarthritis is the most common arthritic condition, which involves progressive degeneration of articular cartilage. The most recent accomplishments have significantly advanced our understanding on the mechanisms of the disease development and progression. The most intriguing is the growing evidence indicating that extracellular matrix destruction in osteoarthritic articular cartilage resembles that in the hypertrophic zone of fetal growth plate during endochondral ossification. This suggests common regulatory mechanisms of matrix degradation in OA and in the development and can provide new approaches for the treatment of the disease by targeting reparation of chondrocyte phenotype.

Involvement of inducible nitric oxide synthase and cyclooxygenase-2 in the anti-inflammatory effects of a red orange extract in human chondrocytes

In the present study, a complex of compounds (red orange complex, ROC), obtained from three red orange varieties (Citrus sinensis varieties: Moro, Tarocco and Sanguinello), containing cyanidin glycosides, hydroxycinnamic acids, flavanone glycosides and ascorbic acid, was screened to discover new lead compounds in the suppression of the production of key molecules released during inflammatory events in interleukin-1beta (IL-beta) stimulated human primary chondrocytes. The expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX)-2 and intercellular adhesion molecule-1 (ICAM-1), and the release of nitric oxide, prostaglandin (PG)E(2) and interleukin-8 (IL-8) were determined. Indomethacin was used as an anti-inflammatory drug reference. ROC acts as a potent inhibitor of iNOS and COX-2 gene expression while also suppressing the production of PGE(2) and nitrite in human chondrocytes. In addition, ROC induces a significant decrease in ICAM expression and IL-8 release. These findings suggest that ROC exerts anti-inflammatory effects probably through the suppression of COX-2 and iNOS expression.

Peroxisome proliferator-activated receptor gamma in osteoarthritis

Osteoarthritis (OA) is among the most prevalent chronic human health disorders and the most common form of arthritis. It is a leading cause of disability in developed countries. This disease is characterized by cartilage deterioration, synovitis, and remodeling of the subchondral bone. There is not yet a satisfactory treatment to stop or arrest this disease process. Although several candidates for therapeutic approaches have been put forward, recent studies suggest that activation of the transcription factor peroxisome proliferator-activated receptor gamma (PPARγ) is an interesting target for this disease. PPARγ is a ligand-activated transcription factor and member of the nuclear receptor superfamily. Agonists of PPARγ inhibit inflammation and reduce synthesis of cartilage degradation products both in vitro and in vivo, and reduce the development/progression of cartilage lesions in OA animal models. This review will highlight the recent experimental studies on the presence of PPARγ in articular tissues and its effect on inflammatory and catabolic responses in chondrocytes and synovial fibroblasts, as well as the protective effects of PPARγ ligands in arthritis experimental models. Finally, the role of PPARγ polymorphism in the pathogenesis of OA and related musculoskeletal diseases will also be discussed.

Atomic force microscope investigation of the boundary-lubricant layer in articular cartilage

OBJECTIVE

To determine the roles of superficial zone protein (SZP), hyaluronan (HA), and surface-active phospholipids (SAPL) in boundary lubrication of articular cartilage through systematic enzyme digestion using trypsin, hyaluronidase, and phospolipase-C (PLC) surface treatments.

METHODS

The friction coefficient of articular cartilage surfaces was measured with an atomic force microscope (AFM) before and after enzyme digestion. Surface roughness, adhesion, and stiffness of the articular surface were also measured to determine the mechanism of friction in the boundary lubrication regime. Histology and transmission electron microscopy were used to visualize the surface changes of treatment groups that showed significant friction changes after enzyme digestion.

RESULTS

A significant increase in the friction coefficient of both load-bearing and non load-bearing regions of the joint was observed after proteolysis by trypsin. Treatment with trypsin, hyaluronidase, or PLC did not affect the surface roughness. However, trypsin treatment decreased the adhesion significantly. Results indicate that the protein component at the articular cartilage surface is the main boundary lubricant, with SZP being a primary candidate. The prevailing nanoscale deformation processes are likely plastic and/or viscoelastic in nature, suggesting that plowing is the dominant friction mechanism.

CONCLUSIONS

The findings of this study indicate that SZP plays an intrinsic and critical role in boundary lubrication at the articular surface of cartilage, whereas the effects of HA and SAPL on the tribological behavior are marginal.

Protective effects of human placenta extract on cartilage degradation in experimental osteoarthritis

This study investigated the effect of human placenta extract (HPE) on cartilage degradation in vitro MG-63 cells, articular cartilage explants, and in vivo monoiodoacetate (MIA)-induced osteoarthritis (OA). Matrix metalloproteinase (MMP)-2 activity was measured in HPE-treated osteoblastic MG-63 cells. Articular cartilage explants in rabbit were cultured, and the degree of proteoglycan (PG) degradation was assessed by measuring the amount of glycosaminoglycan (GAG) released into the culture medium. Experimental osteoarthritis was induced by intra-articular injection of 3 mg MIA in rats. Beginning 14 d post-MIA injection, HPE was administered intra-articularly once a day for 14 d. The knee joints were assessed by roentgenography, histology, and gelatinase activity. HPE inhibited PG degradation in articular cartilage explants. HPE significantly reduced deformity of knee joints and suppressed the histological change in MIA-induced OA. HPE inhibited MMP-2 activity in MG-63 cells. MMP-2 and -9 activities were also reduced in the cartilages of HPE-treated knee joints. Our results indicate that HPE has therapeutic effects on OA by protecting cartilage.

Therapeutic effect of Aralia cordata extracts on cartilage protection in collagenase-induced inflammatory arthritis rabbit model

AIM OF THIS STUDY

Aralia cordata has been used to alleviate symptoms of osteoarthritis (OA) in traditional medicine. However, there is no in vivo study related with the therapeutic effects and mechanisms of Aralia cordata. On the basis of this background, our study was designed to examine the cartilage protective and proliferative effects of Aralia cordata by using a collagenase-induced osteoarthritis (CIA) rabbit model.

MATERIALS AND METHODS

The right knees of rabbits were injected intra-articularly with collagenase, and rabbits were orally administered with distilled water (vehicle), Aralia cordata (200mg/kg) and celecoxib (100mg/kg) once a day for 28 days after the initiation of the CIA.

RESULTS

In histopathologic studying by using H&E and Safranin O staining, Aralia cordata showed a cartilage protective effect in CIA rabbit femoral condyle. However, celecoxib had no effect on cartilage protection in CIA. The inflammatory mediators involved in cartilage destruction, such as COX-2 and PGE(2), were inhibited in the Aralia cordata-treated group. Aralia cordata also showed an anti-apoptotic effect through suppression of caspase-3 activity and chondrocyte proliferation induction in both in vivo and in vitro.

CONCLUSION

These results indicate that Aralia cordata showed cartilage protective effects through the down-regulations of COX-2 expression, PGE(2) production, caspase-3 activity, and chondrocyte proliferation in the CIA rabbit model.

Protective effects of butanol fraction from Betula platyphyla var. japonica on cartilage alterations in a rabbit collagenase-induced osteoarthritis

AIM OF THIS STUDY

Many cartilage protective agents have been developed from natural products, and they have resulted in the development of treatments for osteoarthritis. In this study, we determined the osteoarthritic efficacy and mechanism of butanol fraction from the bark of Betula platyphylla var. japonica (BFBP) in collagenase-induced rabbit model of osteoarthritis (CIA).

MATERIALS AND METHODS

The right knees of rabbits were injected intra-articularly with collagenase, and rabbits were orally administrated with distilled water (vehicle), BFBP (50, 100 and 200 mg/kg) or celecoxib (100 mg/kg) once a day for 28 days after the initiation of the CIA.

RESULTS

Oral administration of BFBP dose-dependently suppressed the stiffness and global histologic score. Proteoglycan intensity was considerably increased in a dose-dependent manner. As well, the mRNA expression of MMP-1, and MMP-3 was decreased. On the contrary, the level of TIMP-1 in the synovial fluids was significantly increased in the BFBP treated group. The pathologic inflammatory molecules such as PGE2 and COX-2 were inhibited by BFBP, but COX-1 expression not affected.

CONCLUSION

We suggest that BFBP has shown the protective effect on cartilage alternations through balance of MMPs/TIMP-1 and regulates inflammatory-related molecules in vivo model of osteoarthritis, and great candidate for development of osteoarthritis treatment.