Experimental Model Of Osteoarthritis Research Articles

Collagenase-Induced Osteoarthritis in Mice.

The collagenase-induced experimental osteoarthritis model is in general applied in mice but can also be used in other small species. The model is mainly based on the induction of joint laxity but has also a major inflammatory component. In this chapter, the induction is described by two injections of collagenase at the start of the model. Investigators who will use this model have to have ample experience in intra-articular injection in mice.

MiR-99a alleviates apoptosis and extracellular matrix degradation in experimentally induced spine osteoarthritis by targeting FZD8

BackgroundOur previous study identified miR-99a as a negative regulator of early chondrogenic differentiation. However, the functional role of miR-99a in the pathogenesis of osteoarthritis (OA) remains unclear.MethodsWe examined the levels of miR-99a and Frizzled 8 (FZD8) expression in tissue specimens. Human SW1353 chondrosarcoma cells were stimulated with IL-6 and TNF-α to construct an in vitro OA environment. A luciferase reporter assay was performed to analyze the relationship between miR-99a and FZD8. CCK-8 assays, flow cytometry, and ELISA assays were used to assess cell viability, apoptosis, and inflammatory molecule expression, respectively. Percutaneous intra-spinal injections of papain mixed solution were performed to create an OA Sprague–Dawley rat model. Alcian Blue staining, Safranin O Fast Green staining, and Toluidine Blue O staining were performed to detect the degrees of cartilage injury.ResultsMiR-99a expression was downregulated in the severe spine OA patients when compared with the mild spine OA patients, and was also decreased in the experimentally induced in vitro OA environment when compared with the control environment. Functionally, overexpression of miR-99a significantly suppressed cell apoptosis and extracellular matrix degradation stimulated by IL-6 and TNF-α. FZD8 was identified as a target gene of miR-99a. Furthermore, the suppressive effects of miR-99a on cell injury induced by IL-6 and TNF-α were reversed by FZD8 overexpression. Moreover, the levels of miR-99a expression were also reduced in the induced OA model rats, and miR-99a agomir injection relieved the cartilage damage. At the molecular level, miR-99a overexpression downregulated the levels of MMP13, β-catenin, Bax, and caspase-3 protein expression and upregulated the levels of COL2A1 and Bcl-2 protein expression in the in vitro OA-like chondrocyte model and also in the experimental OA model rats.ConclusionsOur data showed that miR-99a alleviated apoptosis and extracellular matrix degradation by targeting FZD8, and thereby suppressed the development and progression of experimentally induced spine osteoarthritis.

Improved Joint Health Following Oral Administration of Glycosaminoglycans with Native Type II Collagen in a Rabbit Model of Osteoarthritis.

Simple SummaryOsteoarthritis is an incurable chronic disease. For this reason, new therapies are constantly emerging to improve clinical signs and the quality of life of our pets. Chondroitin sulfate, glucosamine and hyaluronic acid have been proven effective and are the most widely used in many formulations. In the present study, adding native type II collagen to the combination of chondroitin sulfate, glucosamine and hyaluronic acid showed improvements on osteoarthritis progression in an experimental model of osteoarthritis induced by transection of the cranial cruciate ligament of the knee in New Zealand white rabbits. Disease progression was monitored at different time points using magnetic resonance imaging biomarkers, measurement of hyaluronic acid in synovial fluid, and macroscopic and microscopic evaluations of cartilage, synovial membrane and subchondral bone. Overall, our results showed that adding native type II collagen to a combination of glycosaminoglycans allows a significantly slower osteoarthritis progression, compared to glycosaminoglycans alone.A prospective, experimental, randomized, double blinded study was designed to evaluate the effects of glycosaminoglycans, with or without native type II collagen (NC), in an osteoarthritis model induced by cranial cruciate ligament transection. The following compounds were tested: chondroitin sulfate (CS), glucosamine hydrochloride (GlHCl), hyaluronic acid (HA) and NC. Fifty-four female 12-week-old New Zealand rabbits were classified into three groups: CTR (control–no treatment), CGH (CS + GlHCl + HA) and CGH-NC (CS + GlHCl + HA + NC). Each group was subdivided into three subgroups according to survival times of 24, 56 and 84 days. Over time, all rabbits developed degenerative changes associated with osteoarthritis. CGH-NC showed significantly improved values on macroscopic evaluation, compared to CTR and CGH. Microscopically, significantly better results were seen with CGH and CGH-NC, compared to CTR, and synovial membrane values were significantly better with CGH-NC compared to CGH. A significant improvement in magnetic resonance imaging biomarkers was also observed with CGH-NC in cartilage transversal relaxation time (T2) and subchondral bone D2D fractal dimension in the lateral condyle. In conclusion, our results show beneficial effects on joint health of CGH and CGH-NC and also supports that adding NC to CGH results in even greater efficacy.

Макроскопічні зміни колінного суглобу при внутрішньосуглобовому та внутрішньом’язовому введенні хондроїтину сульфату на тлі експериментального остеоартрозу

The purpose of the study was to investigate macroscopic changes in the knee joint during intraarticular and intramuscular administration of chondroitin sulfate to laboratory rabbits in experimental osteoarthritis. Materials and methods. Experimental studies were performed on nonlinear, healthy 16 adult Chinchilla rabbits (8 males and 8 females) weighing 2.5 kg. The experimental model of osteoarthritis was based on the introduction of a solution of monoiodoacetic acid into the knee joint at the rate of 3 mg per 50 μl of sterile saline. Chondroitin sulfate was administered intraarticularly and intramuscularly. Chondroitin sulfate was administrated intraarticularly 0.24 ml 1 time in 3 days 5 times on 28, 31, 34, 37 and 40 days of the experiment and intramuscularly – 0.24 ml 1 time per day every other day for 25 days (from the 28th day of the experiment to the 53rd day). The analysis of macroscopic assessment of rabbit knee joints was performed. Results and discussion. Intramuscular and intraarticular injection of chondroitin sulfate reduces the intensity of the degenerative-dystrophic process due to the impact on inflammatory and the activation of anabolic mechanisms. Intraarticular administration of chondroitin sulfate leads to a greater increase in the level of factors of bone and cartilage formation and a greater decrease in the levels of factors of the acute phase of inflammation and factors that destroy the cartilage matrix. In our study, we attempted to visualize and compare morphological changes in intraarticular and intramuscular administration of chondroitin sulfate on the background of experimental osteoarthritis. The study highlights the possibility of using chondroitin sulfate in intraarticular administration, identified the effectiveness and impact on macroscopic changes in the tissues of the knee joint, assessed differences from intramuscular use in experimental osteoarthritis. However, in view of our research, it is not necessary to claim that all chondroitin sulfate drugs will have a similar effect. It should be remembered that the effectiveness of chondroitin sulfate depends on many factors, including the quality of raw materials. Conclusion. Intramuscular administration of chondroitin sulfate revealed a lower intensity of destructive changes in the cartilaginous surface of the knee joint, and intraarticular – the absence of cartilage destruction and defects of the cartilaginous surface, which indicates the peculiarity of the topical effect of the chondroitin sulfate

Synergistic Effect of L-Carnosine and Hyaluronic Acid in Their Covalent Conjugates on the Antioxidant Abilities and the Mutual Defense against Enzymatic Degradation.

Hyaluronic acid (Hy) is a natural linear polymer that is widely distributed in different organisms, especially in the articular cartilage and the synovial fluid. During tissue injury due to oxidative stress, Hy plays an important protective role. All the beneficial properties of Hy make the polymer attractive for many biomedical uses; however, the low stability and short biological half-life limit Hy application. To overcome these problems, the addition of small antioxidant molecules to Hy solution has been employed to protect the molecular integrity of Hy or delay its degradation. Carnosine (β-alanyl-L-histidine, Car) protects cells from the damage due to the reactive species derived from oxygen (ROS), nitrogen (RNS) or carbonyl groups (RCS). Car inhibits the degradation of hyaluronan induced by free radical processes in vitro but, like Hy, the potential protective action of Car is drastically hampered by the enzymatic hydrolysis in vivo. Recently, we conjugated Hy to Car and the derivatives (HyCar) showed protective effects in experimental models of osteoarthritis and rheumatoid arthritis in vivo. Here we report the antioxidant activity exerted by HyCar against ROS, RNS and RCS. Moreover, we tested if the covalent conjugation between Hy and Car inhibits the enzymatic hydrolysis of the polymer and the dipeptide backbone. We found that the antioxidant properties and the resistance to the enzymatic hydrolysis of Hy and Car are greatly improved by the conjugation.

AUTOMATIC DETECTION OF OSTEOPHYTES FROM CONTRAST ENHANCED μCT-IMAGED RAT TIBIAS USING STATISTICAL SHAPE MODELS

Purpose: Osteophyte (OsP) formation is an important feature of osteoarthritis (OA). Better tools to study OsP formation in detail can yield important insight into OA progression and aid in phenotyping the disease more accurately. Identifying OsPs, as well as their precursors, in pre-clinical OA models is especially important when studying early OA and disease modifying treatments using animal models. OsPs may develop prior to articular cartilage degeneration and their development can be especially rapid in experimental OA models with artificially induced OA.

A green-lipped mussel reduces pain behavior and chondrocyte inflammation and attenuated experimental osteoarthritis progression.

The green-lipped mussel (GLM) contains novel omega-3 polyunsaturated fatty acids, which exhibit anti-inflammatory and joint-protecting properties. Osteoarthritis (OA) is a degenerative joint disease characterized by a progressive loss of cartilage; oxidative stress plays a role in the pathogenesis of OA. The objectives of this study were to investigate the in vivo effects of the GLM on pain severity and cartilage degeneration using an experimental rat OA model, and to explore the mode of action of GLM. OA was induced in rats by intra-articular injection of monosodium iodoacetate (MIA) into the knee. Oral GLM was initiated on the day after 3dyas of MIA injection. Limb nociception was assessed by measuring the paw withdrawal latency and threshold. Samples were analyzed both macroscopically and histologically. Immunohistochemistry was used to investigate the expression of interleukin-1β (IL-1β), IL-6, nitrotyrosine, and inducible nitric oxide synthase (iNOS) in knee joints. Also, the GLM was applied to OA chondrocyte, and the expression on catabolic marker and necroptosis factor were evaluated by real-time polymerase chain reaction. Administration of the GLM improved pain levels by preventing cartilage damage and inflammation. GLM significantly attenuated the expression levels of mRNAs encoding matrix metalloproteinase-3 (MMP-3), MMP-13, and ADAMTS5 in IL-1β-stimulated human OA chondrocytes. GLM decreased the expression levels of the necroptosis mediators RIPK1, RIPK3, and the mixed lineage kinase domain-like protein (MLKL) in IL-1β-stimulated human OA chondrocytes. Thus, GLM reduced pain and cartilage degeneration in rats with experimentally induced OA. The chondroprotective properties of GLM included suppression of oxidative damage and inhibition of catabolic factors implicated in the pathogenesis of OA cartilage damage. We suggest that GLM may usefully treat human OA.

Supercritical carbon dioxide decellularized porcine cartilage graft with PRP attenuated OA progression and regenerated articular cartilage in ACLT-induced OA rats.

Knee osteoarthritis (OA) is a common degenerative articular disorder and considered one of the primary causes of pain and functional disability. Knee OA is prevalent in 10% of men and 13% of women aged 60years above. The study aims to use cartilage tissue engineering that combines the triads of decellularized porcine cartilage graft as "scaffold," plasma rich platelet (PRP) as "signal" and chondrocytes from rat as "cell" to attenuate ACLT-induced OA progression and regenerate the knee cartilage in rats. Decellularization of the porcine cartilage was characterized by hematoxylin and eosin, 4,6-Diamidino-2-phenylindole staining, scanning electron microscopy and residual DNA quantification. The protective effect of decellularized porcine cartilage graft (dPCG) was evaluated by intra-articular administration in surgically induced anterior cruciate ligament transection (ACLT) rat osteoarthritis (OA) model. Supercritical carbon dioxide technology completely decellularized the porcine cartilage. Intra-articular administration of dPCG with or without PRP significantly reduced the ACLT-induced OA symptoms and attenuated the OA progression. Pain-relief by dPCG with or without PRP was assessed by capacitance meter and improved articular cartilage damage in the rat knee was characterized by X-ray and micro-CT. Besides, the histological analysis depicted cartilage protection by dPCG with or without PRP. The repairation and attenuation effect by dPCG with or without PRP in the articular knee cartilage damage were also explored by safranin-O, type II collagen, aggrecan and SOX-9 immuno-staining. To conclude, intra-articular administration of dPCG with or without PRP is efficient in repairing the damaged cartilage in the experimental OA model.

Effects of photobiomodulation therapy in chondrocyte response by in vitro experiments and experimental model of osteoarthritis in the knee of rats.

The purpose of this study is to evaluate the effects of photobiomodulation (PBM) therapy in chondrocyte response by in vitro experiments and cartilage repair using an experimental model of osteoarthritis (OA) in the knee of rats. The in vitro experiment was performed with chondrocyte cells, and they were divided into two groups: non-irradiated and irradiated with PBM (808nm; 0.8J or 1.4J). Then, cell proliferation was evaluated after 1, 3, and 5days. The experimental model of osteoarthritis (OA) was performed in the knee of 64 Wistar rats, and they were assorted into control group (CG), PBM (808nm; 1.4J). The results of in vitro showed that PBM 1.4J increased cell proliferation, on days 1 and 5. However, after 3days was demonstrated a significant increase in cell proliferation in PBM 0.8J. The in vivo experiment results demonstrated, on histological analysis, that PBM presented less intense signs of tissue degradation with an initial surface discontinuity at the superficial zone and disorganization of the chondrocytes in the cartilage region when compared to CG, after 4 and 8weeks. These findings were confirmed by immunohistochemistry and qRT-PCR analysis which showed that PBM increased IL-4, IL-10, COL-2, Aggrecan, and TGF-β which are anabolic factors and acts on extracellular matrix. Also, PBM reduces the IL1-β, an inflammatory marker that operates as a catabolic factor on articular cartilage. In conclusion, these results suggest that PBM may have led to a return to tissue homeostasis, promoting chondroprotective effects and stimulating the components of the articular tissue.

In vitro detection of structural changes in chondrogenic mesenchymal stem cell pellets at the nano-scale using nano-sensitive optical coherance tomography

In vitro detection of structural changes in chondrogenic mesenchymal stem cell pellets at the nano-scale using nano-sensitive optical coherance tomography

Evaluation of the effect of an ayurvedic formulation Myostaal Forte tablets on chondroprotective biomarkers in an experimental model of osteoarthritis in rats

BackgroundOsteoarthritis is a chronic progressive disease commonly affecting the hip and knee joints. Although many drugs are available and afford symptomatic relief, their side effects pose limitations to their continuous use. IntroductionMyostaal Forte (MF) is a poly-herbal Ayurvedic formulation that has shown protection against damage to the chondrocyte layer on histopathological examination in previous studies. But biomarkers which are indicative of chondroprotection have not been assessed. So, the present study was planned to reconfirm the protective effect of MF in osteoarthritic rats by histopathology and create a more substantial evidence by assessing the levels of Cartilage oligomeric matrix protein (COMP) and matrix metalloproteinase-13 (MMP-13). Methods32 rats were divided into four groups (n = 8 each group); sham control (SC), disease control (DC), positive control (PC) and a MF group. Behavioural tests were compared from baseline to 7th day, 14th day, 21st day and on 28th day. Histopathology and bone markers were compared on the 28th day. p < 0.05 was considered as statistically significant. Analysis of Variance (ANOVA) with post hoc Tukey's test was used for parametric data. Non-parametric data was analysed using Kruskal Wallis test with post hoc Dunn's test. ResultsOn measurement of locomotor activity, number of squares crossed was significantly higher in MF group when compared to DC group & there was a significant decrease in the immobility time in MF group when compared DC group. Number of falls on Rota rod test was significantly lower in MF group when compared to DC on day 28. Hot Plate Analgesiometer showed no significant difference in the MF group compared to DC group but over the period of time till day 28, the latency time to lick hind paw was higher in the MF group compared to DC group. In histopathology grading, the scores in MF group were significantly reduced compared to DC group. MMP-13 levels and COMP levels in MF group were significantly decreased as compared to the DC and were statistically significant (p < 0.05). ConclusionMyostaal Forte has shown antiarthritic effect by virtue of its chondroprotective action.

Periostin loss-of-function protects mice from post-traumatic and age-related osteoarthritis

BackgroundElevated levels of periostin (Postn) in the cartilage and bone are associated with osteoarthritis (OA). However, it remains unknown whether Postn loss-of-function can delay or prevent the development of OA. In this study, we sought to better understand the role of Postn in OA development and assessed the functional impact of Postn deficiency on post-traumatic and age-related OA in mice.MethodsThe effects of Postn deficiency were studied in two murine experimental OA models using Postn−/− (n = 32) and littermate wild-type (wt) mice (n = 36). Post-traumatic OA was induced by destabilization of the medial meniscus (DMM) in 10-week-old mice (n = 20); age-related OA was analyzed in 24-month-old mice (n = 13). Cartilage degeneration was assessed histologically using the OARSI scoring system, and synovitis was evaluated by measuring the synovial lining cell layer and the cells density in the synovial stroma. Bone changes were measured by μCT analysis. Serum levels of Postn were determined by ELISA. Expression of Postn and collagenase-3 (MMP-13) was measured by immunostaining. RNA-seq was performed on chondrocytes isolated from 21-day old Postn−/− (n = 3) and wt mice (n = 3) to discover genes and pathways altered by Postn knockout.ResultsPostn−/− mice exhibited significantly reduced cartilage degeneration and OARSI score relative to wt mice in post-traumatic OA after 8 weeks (maximum: 2.37 ± 0.74 vs. 4.00 ± 1.20, P = 0.011; summed: 9.31 ± 2.52 vs. 21.44 ± 6.01, P = 0.0002) and spontaneous OA (maximum: 1.93 ± 0.45 vs. 3.58 ± 1.16, P = 0.014; summed: 6.14 ± 1.57 vs. 11.50 ± 3.02, P = 0.003). Synovitis was significantly lower in Postn−/− mice than wt only in the DMM model (1.88 ± 1.01 vs. 3.17 ± 0.63; P = 0.039). Postn−/− mice also showed lower trabecular bone parameters such as BV/TV, vBMD, Tb.Th, and Tb.N and high Tb. Sp in both models. Postn−/− mice had negligible levels of serum Postn compared with wt. Immunofluorescent studies of cartilage indicated that Postn−/− mice expressed lower MMP-13 levels than wt mice. RNA-seq revealed that cell-cell-adhesion and cell-differentiation processes were enriched in Postn−/− mice, while those related to cell-cycle and DNA-repair were enriched in wt mice.ConclusionsPostn deficiency protects against DMM-induced post-traumatic and age-related spontaneous OA. RNA-seq findings warrant further investigations to better understand the mechanistic role of Postn and its potential as a therapeutic target in OA.

The NC1 fragment of type X collagen measured in serum as a potential biomarker of osteoarthritis

Purpose: The chondrocytes taking a terminal differentiation route of hypertrophy, invasion of blood vessels from the subchondral bone, apoptosis, and calcification of cartilage has been observed in experimental models of OA and human osteoarthritis (OA). Hypertrophy-like changes in chondrocytes are recently believed to play a role in the initiation and progression of cartilage degeneration. Type X collagen, a well-known marker of hypertrophy chondrocytes, plays a role in facilitating and regulating endochondral ossification of cartilage.

Changes in small non-coding RNA expression in synovial fluid during disease progression in an equine model of experimental osteoarthritis

Purpose: Osteoarthritis (OA) is a disease affecting all joint tissues. The ability to identify OA early, prevent the initial cartilage breakdown and stimulate repair would provide an effective strategy for both its prevention and treatment. Synovial fluid (SF) represents a potential source of disease-specific small non-coding RNAs (sncRNAs) that could be used as biomarkers and aid in the understanding of the pathogenesis of OA. SncRNAs are short, typically less than 200 base pairs (bp), RNA species, which are not translated into protein but have other structural or regulatory roles.

Histological changes following the administration of two different chondroitin sulfate products in experimental osteoarthritis models in rats

Introduction. Osteoarthritis (OA) is generally a progressive disease that affects synovial joints, resulting in abnormalities to articular cartilage subchondral bone, synovium, and adjacent soft tissues. Aim. The purpose of this work was to examine the histological changes in knee cartilage and bone following the administration of two different chondroitin sulfate products in two experimental OA models in rats. Material and methods. OA was induced in rats by either a single injection of mono-iodoacetate or four once-weekly injections of dexamethasone. 70 adult rats were included: 30 received mono-iodoacetate, 30 received dexamethasone and the 10 remaining controls received no injection. Samples of knee bone and cartilage were then analyzed histologically. Results. Animals with OA that received CS had significantly less inflammation, improved motor activity, and better analgesia compared with those that did not receive CS, with little difference between products. Histologically, both products reduced the signs of OA and resulted in the activation of regenerative processes of cartilage and bone and stimulation of proliferation and formation of amorphous material. Conclusion. These results substantiate the importance of using high-quality pharmaceutical-grade CS to ensure optimal efficacy and safety of the final product in patients with OA.

Melatonin Prevents Cartilage Degradation in Early-Stage Osteoarthritis Through Activation of miR-146a/NRF2/HO-1 Axis.

Reactive oxygen species (ROS) are implicated in induction of inflammatory response and cartilage degradation in osteoarthritis (OA). Melatonin has been shown to improve the chondrogenic differentiation and promote cartilage matrix synthesis in mesenchymal stem cells. However, the underlying mechanisms of melatonin-regulated antioxidant activity in OA cartilage are not known. The aim of this study was to explore the effect of melatonin on nuclear factor-erythroid 2-related factor 2 (NRF2), a key antioxidant transcription factor, and its target antioxidant genes in early-stage OA cartilage. Primary chondrocytes were isolated from rats with surgically induced OA. In vitro treatment of melatonin significantly increased cartilage matrix synthesis and upregulated antioxidant enzymes, mainly heme oxygenase 1 (HO-1), while decreasing matrix degradation enzymes and intracellular ROS. In vivo intraarticular injection of melatonin effectively ameliorated cartilage degeneration in an experimental rat OA model. Inhibition of melatonin membrane receptors by Luzindole or 4-P-PDOT reversed the beneficial effects of melatonin on cartilage matrix synthesis, implying that melatonin receptor-mediated pathway is involved in its anti-arthritic effects. Interestingly, melatonin showed no significant effect on the mRNA level of Nrf2 but significantly increased its protein level. Silencing of Nrf2 or HO-1 expression abolished the protective effects of melatonin, as shown by increased ROS levels and matrix degradation enzyme expression. Microarray assays revealed that miR-146a, a predicted target for Nrf2, was significantly upregulated in OA chondrocytes but was markedly reduced by melatonin treatment. Overexpression of miR-146a diminished the protective effects of melatonin by inhibiting NRF2 expression and aggravating OA-induced cartilage degradation. These findings demonstrate that melatonin supports the anabolic metabolism of cartilage matrix in OA chondrocytes by enhancing the protein levels of NRF2 via suppressing miR-146a. Melatonin-mediated activation of the NRF2/HO-1 axis prevents cartilage degeneration and represents a promising therapeutic target for treatment of early-stage OA. © 2022 American Society for Bone and Mineral Research (ASBMR).

EZH2 inhibition reduces cartilage loss and functional impairment related to osteoarthritis

Histone methyltransferase EZH2 is upregulated during osteoarthritis (OA), which is the most widespread rheumatic disease worldwide, and a leading cause of disability. This study aimed to assess the impact of EZH2 inhibition on cartilage degradation, inflammation and functional disability. In vitro, gain and loss of EZH2 function were performed in human articular OA chondrocytes stimulated with IL-1β. In vivo, the effects of EZH2 inhibition were investigated on medial meniscectomy (MMX) OA mouse model. The tissue alterations were assayed by histology and the functional disabilities of the mice by actimetry and running wheel. In vitro, EZH2 overexpression exacerbated the action of IL-1β in chondrocytes increasing the expression of genes involved in inflammation, pain (NO, PGE2, IL6, NGF) and catabolism (MMPs), whereas EZH2 inhibition by a pharmacological inhibitor, EPZ-6438, reduced IL-1β effects. Ex vivo, EZH2 inhibition decreased IL-1β-induced degradation of cartilage. In vivo, intra-articular injections of the EZH2 inhibitor reduced cartilage degradation and improved motor functions of OA mice. This study demonstrates that the pharmacological inhibition of the histone methyl-transferase EZH2 slows the progression of osteoarthritis and improves motor functions in an experimental OA model, suggesting that EZH2 could be an effective target for the treatment of OA by reducing catabolism, inflammation and pain.

No Effect of Long-Term Risedronate Use on Cartilage and Subchondral Bone in an Experimental Rabbit Model of Osteoarthritis.

Osteoarthritis (OA) is the most prevalent degenerative joint disease in animals and humans. It is characterized by pain, articular cartilage damage and joint stiffness. It has been suggested that the status of the subchondral bone compartment plays an important role in the initiation and progression of OA. Bisphosphonates have been proposed as a potential disease-modifying treatment for OA, however their effectiveness is not yet clear. Twenty-four male adult New Zealand rabbits were used to evaluate the effects of risedronate on the subchondral bone quality and cartilage degradation in a long-term model of experimentally induced OA. Animals underwent an anterior cruciate ligament transection and partial medial meniscectomy or sham operation in only one knee, which was randomly chosen, using the contralateral as healthy control. Animals were divided into three groups (n = 8): untreated control group and sham surgery control group; both groups received only vehicle; and risedronate group, treated with 2.5 mg orally weekly for 24 weeks. Stifle joints were harvested and scanned using a high-resolution micro-CT to evaluate the subchondral plate and trabecular bone changes. The macroscopic evaluation and histological analysis were determined using an adapted Osteoarthritis Research Society International scoring scheme to assess the cartilage degeneration. The lateral and medial femoral condyle and tibial plateau were evaluated. Additionally, the histological synovial membrane assessment was carried out. Sample analysis showed that the experimental model induced osteoarthritic changes in the operated joints, whereas in sham-operated rabbits, almost no histological changes were observed on articular cartilage surfaces. In terms of macroscopic and histological analyses, risedronate-treated animals did not show improved cartilage health compared with untreated operated rabbits, but a slightly anti-inflammatory activity was observed in the synovial membrane. Risedronate administration showed a slight tendency to increase subchondral bone plate thickness in lateral compartments but, it did not show conservation of periarticular bone and was not be able to suppress the osteophyte formation. In conclusion, long-term risedronate use did not demonstrate a positive effect on reducing the cartilage damage, and failed to prevent the subchondral bone changes and osteophytogenesis in an experimental rabbit model of OA.

Effects of photobiomodulation associated with chitosan viscosupplementation for osteoarthritis: an in vitro and in vivo study

The aim of the present study was to investigate the tissue performance of the association of photobiomodulation (PBM) and chitosan hydrogel (Ch), using in vitro and in vivo studies, in culture of chondrocytes and in an experimental model of osteoarthritis (OA) in the knee of rats. The chitosan hydrogel was characterized by pH, gelation time, and degradation rate. For the in vitro study, chondrocyte cells were seeded in the Ch irradiated or not with PBM to assess cell viability and proliferation after 1, 3, and 5 days. For the in vivo study, sixty Wistar rats with OA were randomly distributed: control group (CG), Ch hydrogel injection (Ch), Ch hydrogel injection associated with PBM (Ch/PBM). The characterization results revealed that Ch hydrogels can be controlled precisely by variation of the urea and urease concentrations. The in vitro findings demonstrated that Ch and Ch/PBM are biocompatible and noncytotoxic. The in vivo findings showed that PBM associated with Ch prevented articular degeneration by stimulating anabolic factor (TGF-β) and reducing catabolic factor (TNF-α) and increasing the gene related to components of the cartilage extracellular matrix. In conclusion, the PBM associated with Ch can be used as a cartilage repair application.

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.