Rat Model Of Osteoarthritis Research Articles

Alterations in DNA methylation machinery in a rat model of osteoarthritis of the hip

BackgroundThis study aimed to validate alterations in the gene expression of DNA methylation-related enzymes and global methylation in the peripheral blood mononuclear cell (PBMC) and synovial tissues of animal hip osteoarthritis (OA) models.MethodsAnimals were assigned to the control (no treatment), sham (25 µL of sterile saline), and OA (25 µL of sterile saline and 2 mg of monoiodoacetate) groups. Microcomputed tomography scan, histopathological assessment and pain threshold measurement were performed after induction. The mRNA expression of the DNA methylation machinery genes and global DNA methylation in the PBMC and hip synovial tissue were evaluated.ResultsThe OA group presented with hip joint OA histopathologically and radiologically and decreased pain threshold. The mRNA expression of DNA methyltransferase (Dnmt 3a), ten–eleven translocation (Tet) 1 and Tet 3 in the synovial tissue of the OA group was significantly upregulated. Global DNA methylation in the synovial tissue of the OA group was significantly higher than that of the control and sham groups.ConclusionsThe intra-articular administration of monoiodoacetate induced hip joint OA and decreased pain threshold. The DNA methylation machinery in the synovial tissues of hip OA was altered.

Time-Dependent Effect of Eggshell Membrane on Monosodium-Iodoacetate-Induced Osteoarthritis: Early-Stage Inflammation Control and Late-Stage Cartilage Protection.

Osteoarthritis (OA) is a chronic degenerative joint disease that causes chronic pain, swelling, stiffness, disability, and significantly reduces the quality of life. Typically, OA is treated using painkillers and non-steroidal anti-inflammatory drugs (NSAIDs). While current pharmacologic treatments are common, their potential side effects have prompted exploration into functional dietary supplements. Recently, eggshell membrane (ESM) has emerged as a potential functional ingredient for joint and connective tissue disorders due to its clinical efficacy in relieving joint pain and stiffness. Despite promising clinical evidence, the effects of ESM on OA progression and its mechanism of action remain poorly understood. This study evaluated the efficacy of Ovomet®, a powdered natural ESM, against joint pain and disease progression in a monosodium iodoacetate (MIA)-induced rodent model of OA in mice and rats. The results demonstrate that ESM significantly alleviates joint pain and attenuates articular cartilage destruction in both mice and rats that received oral supplementation for 5 days prior to OA induction and for 28 days thereafter. Interestingly, ESM significantly inhibited mRNA expression levels of pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), and interleukin-6 (IL-6), as well as inflammatory mediators, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase in the knee joint cartilage at the early stage of OA, within 7 days after OA induction. However, this effect was not observed in the late stage at 28 days after OA induction. ESM further attenuates the induction of protein expression for cartilage-degrading enzymes like matrix metalloproteinase (MMPs) 3 and 13, and a disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5), in the late-stage. In addition, MIA-induced reduction of the protein expression levels of cartilage components, cartilage oligomeric matrix protein (COMP), aggrecan (ACAN) and collagen type II α-1 chain (COL2α1), and cartilage extracellular matrix (ECM) synthesis promoting transcriptional factor SRY-Box 9 (SOX-9) were increased via ESM treatment in the cartilage tissue. Our findings suggest that Ovomet®, a natural ESM powder, is a promising dietary functional ingredient that can alleviate pain, inflammatory response, and cartilage degradation associated with the progression of OA.

In vitro and in vivo studies of the therapeutic potential of Tinospora crispa extracts in osteoarthritis: Targeting oxidation, inflammation, and chondroprotection

Ethnopharmacological relevanceThe increasing incidence of osteoarthritis (OA), especially among the elderly population, highlights the need for more efficacious treatments that go beyond mere symptomatic relief. Tinospora crispa (L.) Hook. f. & Thomson (TC) boasts a rich traditional heritage, widespread use in Ayurveda, traditional Chinese medicine (TCM), and diverse indigenous healing practices throughout Southeast Asia for treating arthritis, rheumatism, fever, and inflammation. Aim of the studyThis study investigates the anti-inflammatory and chondroprotective potential of TC stem extracts, including ethanolic TC extract (ETCE) and aqueous TC extract (ATCE), in modulating OA pathogenesis through in vitro and in vivo approaches. Materials and methodsThe study utilized LC-MS/MS to identify key compounds in TC stem extracts. In vitro experiments assessed the antioxidative and anti-inflammatory properties of ETCE and ATCE in activated macrophages, while an in vivo monoiodoacetate (MIA)-induced OA rat model evaluated the efficacy of ETCE treatment. Key markers of oxidative stress, such as superoxide dismutase (SOD) and catalase (CAT), were assessed alongside pro-inflammatory cytokines TNF-α and IL-1β, and matrix-degrading enzymes, matrix metalloproteinase (MMP 13 and MMP 3), to evaluate the therapeutic effects of TC stem extracts on OA. ResultsChemical profiling of the extracts was conducted using LC-MS/MS in positive ionization, identifying seven compounds, including pseudolaric acid B, stylopine, and reticuline, which were reported for the first time in this species. The study utilized varying concentrations of TC stem extracts, specifically 6.25–25 μg/mL for in vitro assays and 500 mg/kg for in vivo studies. Our findings also revealed that both ETCE and ATCE exhibit dose-dependent reduction in reactive oxygen species (41%–52%) and nitric oxide (NO) levels (50% and 72%), with ETCE displaying superior antioxidative efficacy and marked anti-inflammatory properties, significantly reducing TNF-α and IL-6 at concentrations above 12.5 μg/mL. In the MIA-induced OA rat model, ETCE treatment notably outperformed ATCE, markedly lowering TNF-α (1.91 ± 0.37 pg/mL) and IL-1β (26.30 ± 3.68 pg/mL) levels and effectively inhibiting MMP 13 and MMP 3 enzymes. Furthermore, macroscopic and histopathological assessments, including ICRS scoring and OARSI grading, indicate that TC stem extracts reduce articular damage and proteoglycan loss in rat knee cartilage. These results suggest that TC stem extracts may play a role in preventing cartilage degradation and potentially alleviating inflammation and pain associated with OA, though further studies are needed to confirm these effects. ConclusionThis study highlights the potential of TC stem extracts as a novel, chondroprotective therapeutic avenue for OA management. By targeting oxidative stress, pro-inflammatory cytokines, and cartilage-degrading enzymes, TC stem extracts promise to prevent cartilage degradation and alleviate inflammation and pain associated with OA.

Injectable dECM-enhanced hyaluronic microgels with spatiotemporal release of cartilage-specific molecules to improve osteoarthritic chondrocyte’s function

The interior environment of articular cartilage in osteoarthritis (OA) presents substantial hurdles, leading to the malfunction of chondrocytes and the breakdown of collagen II-enriched hyaline cartilage matrix. Despite this, most clinical treatments primarily provide temporary relief from OA discomfort without arresting OA progression. This study aimed to alleviate OA by developing intra-articular injectable dECM-enhanced hyaluronic (HE) microgels. The HE hydrogel was engineered and shaped into uniformly sized microgels using microfluidics and photopolymerization techniques. These microgels provided a spatiotemporal cascade effect, facilitating the rapid release of growth factors and a slower release of ECM macromolecules and proteins. This process assisted in the recovery of OA chondrocytes’ function, promoting cell proliferation, matrix synthesis, and cartilage-specific gene expression in vitro. It also effectively aided repair of the collagen II-enriched hyaline cartilage and significantly reduced the severity of OA, as demonstrated by radiological observation, gross appearance, histological/immunohistochemical staining, and analysis in an OA rat model in vivo. Collectively, the HE injectable microgels with spatiotemporal release of cartilage-specific molecules have shown promise as a potential candidate for a cell-free OA therapy approach.Graphical

Novel poly(lactic-co-glycolic acid) nanoliposome-encapsulated diclofenac sodium and celecoxib enable long-lasting synergistic treatment of osteoarthritis.

Diclofenac sodium (DS) and celecoxib (CEL) are primary anti-inflammatory agents used in the treatment of osteoarthritis (OA). Formulating these drugs into extended-release versions can effectively address the issue of multiple daily doses. In this study, we designed and synthesized a novel poly(lactic-co-glycolic acid) (PLGA) nanoliposome as a dual-drug delivery sustained-release formulation (PPLs-DS-CEL) to achieve long-lasting synergistic treatment of OA with both DS and CEL. PPLs-DS-CEL was synthesized by the reverse evaporation method and evaluated for its physicochemical properties, encapsulation efficiency, drug release kinetics and biological properties. A rat OA model was established to assess the therapeutic efficacy and biosafety of PPLs-DS-CEL. The particle size of PPLs-DS-CEL was 218.36 ± 6.27nm, with a potential of 32.56 ± 3.28 mv, indicating a homogeneous vesicle size. The encapsulation of DS and CEL by PPLs-DS-CEL was 95.18 ± 4.43% and 93.63 ± 5.11%, with drug loading of 9.56 ± 0.32% and 9.68 ± 0.34%, respectively. PPLs-DS-CEL exhibited low cytotoxicity and hemolysis, and was able to achieve long-lasting synergistic analgesic and anti-inflammatory therapeutic effects in OA through slow release of DS and CEL, demonstrating good biosafety properties. This study developed a novel sustained-release nanoliposomes formulation capable of co-loading two drugs for the long-acting synergistic treatment of OA. It offers a new and effective therapeutic strategy for OA treatment in the clinic settings and presents a promising approach for drug delivery systems.

Effect of amniotic suspension allograft in a rat destabilization of medial meniscus osteoarthritis model.

Placental-derived allografts have been of interest as a potential nonsurgical treatment to reduce pain and improve function in knee osteoarthritis (OA). The purpose of this study was to evaluate the effect of single and repeat injection of amniotic suspension allograft (ASA) on pain, function, and cytokine levels using a destabilization of the medial meniscus (DMM) rat model of OA. Post-DMM surgery, animals were treated with a single injection of either ASA, vehicle, or triamcinolone, or repeated injection of either ASA or vehicle. Behavioral testing including knee swelling, pain threshold, dynamic weight bearing (DWB), and gait analysis were evaluated during the in-life phase. Postsacrifice, histopathology and serum and synovial fluid analyses were evaluated. Significant improvements in both DWB differentials and pain threshold were seen in response to repeated injection of ASA, while a single injection of ASA and triamcinolone resulted in significant improvements in pain threshold. Histopathology analysis found no significant differences regardless of treatment compared to vehicle, except for an increase in synovitis following repeated injection of ASA. A single injection of ASA and triamcinolone resulted in increased anti-inflammatory cytokines; repeated ASA injection resulted in significant increases in several immune-modulating factors relevant to OA. When comparing the impact of single and repeat ASA treatments on behavioral testing, repeated injection provided significant additional improvements in both pain and function. This study provides evidence demonstrating the impact of a second injection while also providing additional data for evaluating the use of ASA as a nonsurgical treatment for knee OA.

Semi-synthetic chondroitin sulfate CS-semi5 upregulates miR-122-5p, conferring a therapeutic effect on osteoarthritis via the p38/MMP13 pathway

Osteoarthritis (OA) is an aging-associated disease characterized by joint stiffness pain and destroyed articular cartilage. Traditional treatments for OA are limited to alleviating various OA symptoms. There is a lack of drugs available in clinical practice that can truly repair cartilage damage. Here, we developed the chondroitin sulfate analog CS-semi5, semi-synthesized from chondroitin sulfate A. In vivo, CS-semi5 alleviated inflammation, provided analgesic effects, and protected cartilage in the modified Hulth OA rat model and papain-induced OA rat model. A bioinformatics analysis was performed on samples from OA patients and an exosome analysis on papain-induced OA rats, revealing miR-122-5p as the key regulator associated with CS-semi5 in OA treatment. Binding prediction revealed that miR-122-5p acted on the 3′-untranslated region of p38 mitogen-activated protein kinase, which was related to MMP13 regulation. Subsequent in vitro experiments revealed that CS-semi5 effectively reduced cartilage degeneration and maintained matrix homeostasis by inhibiting matrix breakdown through the miR-122-5p/p38/MMP13 axis, which was further validated in the articular cartilage of OA rats. This is the first study to investigate the semi-synthesized chondroitin sulfate CS-semi5, revealing its cartilage-protecting, anti-inflammatory, and analgesic properties that show promising therapeutic effects in OA via the miR-122-5p/p38/MMP13 pathway.

Development and functional evaluation of a hyaluronic acid coated nano-formulation with kaempferol as a novel intra-articular agent for Knee Osteoarthritis treatment

Knee osteoarthritis (OA) involves articular cartilage degradation driven mainly by inflammation. Kaempferol (KM), known for its anti-inflammatory property, holds potential for OA treatment. This study investigated the potential of hyaluronic acid (HA)-coated gelatin nanoparticles loaded with KM (HA-KM GNP) for treating knee OA. KM was encapsulated into gelatin nanoparticles (KM GNP) and then coated with HA to form HA-KM GNPs. Physical properties were characterized, and biocompatibility and cellular uptake were assessed in rat chondrocytes. Anti-inflammatory and chondrogenic properties were evaluated using IL-1β-stimulated rat chondrocytes, compared with HA-coated nanoparticles without KM (HA GNP) and KM alone. Preclinical efficacy was tested in an anterior cruciate ligament transection (ACLT)-induced knee OA rat model treated with intra-articular injection of HA-KM GNP. Results show spherical HA-KM GNPs (88.62 ± 3.90 nm) with positive surface charge. Encapsulation efficiency was 98.34 % with a sustained release rate of 18 % over 48 h. Non-toxic KM concentration was 2.5 μg/mL. In IL-1β-stimulated OA rat chondrocytes, HA-KM GNP significantly down-regulated RNA expression of IL-1β, TNF-α, COX-2, MMP-9, and MMP-13, while up-regulating SOX9 compared to HA GNP, and KM. In vivo imaging demonstrated significantly higher fluorescence intensity within rat knee joints for 3 hours post HA-KM GNP injection compared with KM GNP (185.2% ± 34.1% vs. 45.0% ± 16.7%). HA-KM GNP demonstrated significant effectiveness in reducing subchondral sclerosis, attenuating inflammation, inhibiting matrix degradation, restoring cartilage thickness, and reducing the severity of OA in the ACLT rat model. In conclusion, HA-KM GNP holds promise for knee OA therapy.

Botulinum toxin A attenuates osteoarthritis development via inhibiting chondrocyte ferroptosis through SLC7Al1/GPX4 axis

Osteoarthritis (OA) is a prevalent joint degenerative disease, resulting in a significant societal burden. However, there is currently a lack of effective treatment option available. Previous studies have suggested that Botulinum toxin A (BONT/A), a macromolecular protein extracted from Clostridium Botulinum, may improve the pain and joint function in OA patients, but the mechanism remains elusive. This study was to investigate the impact and potential mechanism of BONT/A on OA in vivo and in vitro experiment. LPS increased the levels of ROS, Fe2+and Fe3+, as well as decreased GSH levels, the ratio of GSH / GSSH and mitochondrial membrane potential. It also enhanced the degeneration of extracellular matrix (ECM) and altered the ferroptosis-related protein expression in chondrocytes. BONT/A rescued LPS-induced decrease in collagen type II (Collagen II) expression and increase in matrix metalloproteinase 13 (MMP13), mitigated LPS-induced cytotoxicity in chondrocytes, abolished the accumulation of ROS and iron, upregulated GSH and the ratio of GSH/ GSSH, improved mitochondrial function, and promoted SLC7A11/GPX4 anti-ferroptosis system activation. Additionally, intra-articular injection of BONT/A inhibited the degradation of cartilage in OA model rats. This chondroprotective effect of BONT/A was reversed by erastin (a classical ferroptosis agonist) and enhanced by liproxstatin-1 (a classic ferroptosis inhibitor). Our research confirms that BONT/A alleviates the OA development by inhibiting the ferroptosis of chondrocytes, which revealed to be a potential therapeutic mechanism for BONT/A treating the OA.

Predicting the potential mechanism of radix chimonanthi pracecocis in treating osteoarthritis by network pharmacology analysis combined with experimental validation

Ethnopharmacological relevanceRadix Chimonanthi Pracecocis (RCP), also known as Tiekuaizi, widely used by the Miao community in Guizhou, exhibits diverse biological activities and holds promise for the treatment of osteoarthritis (OA). However, there is a lack of contemporary pharmacological research in this area. Aims of the studyThis study aims to explore the potential of targets and mechanisms of RCP in the treatment of OA. Materials and methodsThe chemical components of RCP were identified using UPLC-MS/MS, and active components were determined based on the Lipinski rule. RCP and OA-related targets were retrieved from public databases such as TCMSP and GeneCards. Network pharmacology approaches were employed to identify key genes. The limma package (version 3.40.2) in R 4.3.2 was used to screen for differentially expressed genes (DEGs) between OA and healthy individuals in GSE82107. DEGs were analyzed using an independent sample t-test and receiver operating characteristic analysis in GraphPad Prism 9.5.1. Additionally, molecular docking (SYBYL2.1.1) was used to analyze the binding interactions between the active components and target proteins. Finally, we established a papain-induced osteoarthritis (OA) rat model and treated it with RCP aqueous extract by gavage. We validated relevant indicators using real-time fluorescence quantitative polymerase chain reaction, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assays. ResultsSeven active components and 53 targets were identified. The results of GO and KEGG enrichment analyses confirmed the significant role of RCP in the regulation of pyroptosis. Hypoxia-inducible factor-1α (HIF-1α) was identified as a key gene involved in the main biological functions. Molecular docking analysis revealed that Praecoxin, Isofraxidin, Esculin, and Naringenin can bind to the nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) (T-Score >5). Additionally, Praecoxin can bind to HIF-1α (T-Score >5). In vivo experiments demonstrated that RCP significantly affects the NLRP3 inflammasome, which is regulated by the HIF-1α pathway. RCP inhibited pyroptosis and reduced synovial inflammation. ConclusionsThis study confirmed the efficacy of RCP aqueous extract in the treatment of OA and identified seven active components (esculin, dihydrokaempferol, naringenin, praecoxin, carnosol, hydroxyvalerenic acid, isofraxidin) that may play an anti-pyroptosis role in the treatment of OA by downregulating the expression of HIF-1α and NLRP3 inflammasome.

Injectable biomimetic hybrid nanofibers for targeting cartilage in early osteoarthritis treatment

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage degradation and limited effective treatment options for regeneration. To address this clinical challenge, an innovative injectable biomimetic hybrid nanofiber, namely hyaluronic acid-graft-poly(2-methacryloyloxyethyl phosphorylcholine)-chondrocyte affinity peptides (HA-PMPC-CAP), was designed and synthesized through a ultraviolet light (UV)-initiated reaction process for intervention of early osteoarthritis (OA). Comprehensive in vitro assessments and molecular docking experiments have confirmed its non-cytotoxicity, exceptional lubrication properties, favorable biocompatibility and high binding affinity to cartilage proteins. Utilizing an OA rat model, the therapeutic potential of HA-PMPC-CAP was explored through intra-articular injection, with a focus on its impact on cartilage regeneration. During an 8-week period, macroscopic, histological, immunohistochemical, and microscopic CT evaluations were conducted on the treated joints. The findings were remarkable: HA-PMPC-CAP established a durable lubricating layer on the surface of cartilage, significantly reduced cartilage deterioration, replenished glycosaminoglycan (GAG) levels, lowered the scores of Osteoarthritis Research Society International (OARSI), and curtailed the development of osteophytes, which was superior to the untreated OA control groups. These results position HA-PMPC-CAP as an effective biomimetic therapy, offering a novel strategy for cartilage regeneration and lubrication in the early stages of OA, which has promising implications for future clinical applications.

Effect of Low-Intensity Pulsed Ultrasound on Macrophage Properties and Fibrosis in the Infrapatellar Fat Pad in a Carrageenan-Induced Knee Osteoarthritis Rat Model.

In the progression of knee osteoarthritis (KOA), fibrosis of the infrapatellar fat pad (IFP) is a key pathological change. Low-intensity pulsed ultrasound (LIPUS) inhibits IFP fibrosis by decreasing the gene expression and activity of hypoxia-inducible factor (HIF-1α), which is a protein involved in IFP fibrosis in KOA rat models. On the other hand, macrophages play an important role in the progression of fibrosis in various tissues, and LIPUS irradiation suppresses macrophage infiltration and inflammatory cytokine secretion. However, whether LIPUS suppresses macrophage polarity and IFP fibrosis in KOA remains unclear. Therefore, we investigated the effect of LIPUS on macrophage polarity and IFP fibrosis. A KOA model was created by injecting carrageenin into the bilateral knee joints of Wistar rats (eight weeks old). Tissues were harvested over time for histological and molecular biological analysis. The KOA model was also subjected to LIPUS irradiation for two weeks following the injection of carrageenin. RM-4-positive cells were widely distributed in IFP two weeks after carrageenin administration, but M2 macrophages were significantly increased, and the Sirius red area was decreased in the LIPUS-irradiated group compared with those in the non-irradiated group. The gene expression of M1 macrophage markers was significantly decreased and that of M2 macrophage markers was significantly increased in the LIPUS-irradiated group. The expression of transforming growth factor-β (TGF-β) and type 1 collagen was also significantly decreased. These results suggest that LIPUS may serve as a novel approach for the treatment of KOA through its effect on M1 macrophages and suppression of TGF-β expression.

OSTF1 knockdown mitigates IL-1β-induced chondrocyte injury via inhibiting the NF-κB signaling pathway

Osteoarthritis (OA) is an age-related joint disease characterized by progressive heterogeneous changes in articular cartilage and subchondral bone. Osteoclast stimulating factor 1 (OSTF1) is a small intracellular protein involved in bone formation and bone resorption. However, to our best knowledge, its role in OA is still unclear. In this study, an OA rat model was established by anterior cruciate ligament transection (ALCT). OSTF1 was increased in the cartilage tissues of OA patients and OA rats. Next, the role of OSTF1 in interleukin-1β (IL-1β)-induced chondrocyte apoptosis, inflammation and extracellular matrix degradation was explored through loss of function assays. Strikingly, OSTF1 knockdown relieved IL-1β-induced chondrocyte apoptosis, with decreased cleaved caspase-3 and cleaved PARP levels. Besides, OSTF1 knockdown restrained IL-1β-induced inflammation and degradation of extracellular matrix of chondrocytes. Subsequently, the molecular mechanism of OSTF1 was explored. Transcriptomic analysis revealed the potential gene network map regulated by OSTF1 knockdown. Some differentially expressed genes (DEGs) were involved in regulating the NF-κB signaling pathway. Furthermore, our results demonstrated that OSTF1 knockdown inhibited IL-1β-activated the NF-κB signaling pathway. Ultimately, we analyzed the potential gene network map regulated by OSTF1 and its downstream NF-κB. Bioinformatics analysis showed that 18 DEGs in OSTF1-silenced chondrocytes overlapped with the NF-κB downstream targets. Collectively, our findings indicate that OSTF1 knockdown mitigates IL-1β-induced chondrocyte injury via inhibiting the NF-κB signaling pathway.

Micro-current stimulation could inhibit IL-1β-induced inflammatory responses in chondrocytes and protect knee bone cartilage from osteoarthritis.

This study aimed to evaluate the inhibitory effects of micro-current stimulation (MCS) on inflammatory responses in chondrocytes and degradation of extracellular matrix (ECM) in osteoarthritis (OA). To determine the efficacy of MCS, IL-1β-treated chondrocytes and monosodium iodoacetate (MIA)-induced OA rat model were used. To evaluate the cytotoxicity and nitric oxide (NO) production in SW1353 cells, the presence or absence of IL-1β treatment or various levels of MCS were applied. Immunoblot analysis was conducted to evaluate whether MCS can modulate IL-1R1/MyD88/NF-κB signaling pathway and various indicators involved in ECM degradation. Additionally, to determine whether MCS alleviates subchondral bone structure destruction caused by OA, micro-CT analysis, immunoblot analysis, and ELISA were conducted using OA rat model. 25 and 50 µA levels of MCS showed effects in cell proliferation and NO production. The MCS group with IL-1β treatment lead to significant inhibition of protein expression levels regarding IL-1R1/MyD88/NF-κB signaling and reduction of the nucleus translocation of NF-κB. In addition, the protein expression levels of MMP-1, MMP-3, MMP-13, and IL-1β decreased, whereas collagen II and aggrecan increased. In animal results, morphological analysis of subchondral bone using micro-CT showed that MCS induced subchondral bone regeneration and improvement, as evidenced by increased thickness and bone mineral density of the subchondral bone. Furthermore, MCS-applied groups showed decreases in the protein expression of MMP-1 and MMP-3, while increases in collagen-II and aggrecan expressions. These findings suggest that MCS has the potential to be used as a non-pharmaceutical method to alleviate OA.

A Dual Functional Bioinspired Lubricant for Osteoarthritis Treatment and Potential Prevention.

Osteoarthritis (OA), primarily characterized by the deterioration of articular cartilage, is a highly prevalent joint-disabling disease. The pathological onset and progression of OA are closely related to cartilage lubrication dysfunction and synovial inflammation. Synergistic options targeted at restorative lubrication and anti-inflammation are expected to be the most attractive candidates to treat OA and perhaps help prevent it. Herein, a bioinspired lubricant (HA/PA@Lipo) was fabricated by combining anionic hyaluronan-graft-poly(2-acrylamide-2-methylpropanesulfonic acid sodium salt) (HA/PA) with cationic liposomes (Lipo) via electrostatic interaction. HA/PA@Lipo mimicked the lubrication complex located on the outer cartilage surface and was endowed cartilage with excellent cartilage-lubricating performances. After the antioxidant gallic acid (GA) was loaded for dual functionality, HA/PA@Lipo-GA was prepared with added anti-inflammatory properties. HA/PA@Lipo-GA showed favorable biocompatibility with C28/I2 cells, inhibited the production of reactive oxygen, and regulated the expression levels of anabolic genes and proteins. The therapeutic effects of HA/PA@Lipo-GA were evaluated using a sodium iodoacetate-induced OA rat model, and the preventive effects of HA/PA@Lipo-GA were estimated in vivo. The results suggested the robust potential of HA/PA@Lipo-GA with dual functions as a candidate option for OA treatment and prevention.

Opsonization Inveigles Macrophages Engulfing Carrier-Free Bilirubin/JPH203 Nanoparticles to Suppress Inflammation for Osteoarthritis Therapy.

Osteoarthritis (OA) is a chronic inflammatory disease characterized by cartilage destruction, synovitis, and osteophyte formation. Disease-modifying treatments for OA are currently lacking. Because inflammation mediated by an imbalance of M1/M2 macrophages in the synovial cavities contributes to OA progression, regulating the M1 to M2 polarization of macrophages can be a potential therapeutic strategy. Basing on the inherent immune mechanism and pathological environment of OA, an immunoglobulin G-conjugated bilirubin/JPH203 self-assembled nanoparticle (IgG/BRJ) is developed, and its therapeutic potential for OA is evaluated. After intra-articular administration, IgG conjugation facilitates the recognition and engulfment of nanoparticles by the M1 macrophages. The internalized nanoparticles disassemble in response to the increased oxidative stress, and the released bilirubin (BR) and JPH203 scavenge reactive oxygen species (ROS), inhibit the nuclear factor kappa-B pathway, and suppress the activated mammalian target of rapamycin pathway, result in the repolarization of macrophages and enhance M2/M1 ratios. Suppression of the inflammatory environment by IgG/BRJ promotes cartilage protection and repair in an OA rat model, thereby improving therapeutic outcomes. This strategy of opsonization involving M1 macrophages to engulf carrier-free BR/JPH203 nanoparticles to suppress inflammation for OA therapy holds great potential for OA intervention and treatment.

Vagotomy accelerates the onset of symptoms during early disease progression and worsens joint-level pathogenesis in a male rat model of chronic knee osteoarthritis

ObjectiveLow vagal tone is common in osteoarthritis (OA) comorbidities and results in greater peripheral inflammation. Characterizing vagal tone's role in OA pathogenesis may offer insights into OA's influences beyond the articular joint. We hypothesized that low vagal tone would accelerate onset of OA-related gait changes and worsen joint damage in a rat knee OA model. MethodsKnee OA was induced in male Sprague Dawley rats by transecting the medial collateral ligament and medial meniscus. Then, left cervical vagus nerve transection (VGX, n ​= ​9) or sham VGX (non-VGX, n ​= ​6) was performed. Gait and tactile sensitivity were assessed at baseline and across 12 weeks, with histology and systemic inflammation evaluated at endpoint. ResultsAt week 4, VGX animals showed limping gait characteristics through shifted stance times from their OA to non-OA limb (p ​= ​0.055; stance time imbalance ​= ​1.6 ​± ​1.6%) and shifted foot strike locations (p ​< ​0.001; spatial symmetry ​= ​48.4 ​± ​0.835%), while non-VGX animals walked with a balanced and symmetric gait. Also at week 4, while VGX animals had a mechanical sensitivity (50% withdrawal threshold) of 13.97 ​± ​7.70 compared to the non-VGX animal sensitivity of 29.74 ​± ​9.43, this difference was not statistically significant. Histologically, VGX animals showed thinner tibial cartilage and greater subchondral bone area than non-VGX animals (p ​= ​0.076; VGX: 0.80 ​± ​0.036 ​mm2; non-VGX: 0.736 ​± ​0.066 ​mm2). No group differences in systemic inflammation were observed at endpoint. ConclusionsVGX resulted in quicker onset of OA-related symptoms but remained unchanged at later timepoints. VGX also had thinner cartilage and abnormal bone remodeling than non-VGX. Overall, low vagal tone had mild effects on OA symptoms and joint remodeling, and not at the level seen in common OA comorbidities.

Cartilage protective and anti-edema effects of JTF in osteoarthritis via inhibiting NCOA4-HMGB1-driven ferroptosis and aquaporin dysregulation

BackgroundPreventing joint edema is crucial in halting osteoarthritis (OA) progression. Growing clinical evidence indicate that Jianpi-Tongluo Formula (JTF) may have a promising anti-edema effect. However, the therapeutic properties of JTF and the underlying mechanisms remains unclear. Materials and methodsAn OA rat model was established and employed to evaluate pharmacological effects of JTF in vivo based on dynamic histopathologic assessments and micro-CT observations. Then, OA-related genes and potential targets of JTF were identified through clinical transcriptomic data analysis and "disease gene-drug target" network analysis, which were verified by a series of in vivo experiments. ResultsJTF administration effectively reduced pain and joint edema, inhibited matrix degradation, chondrocyte apoptosis, and aquaporin expression in OA rats. Notably, JTF dose-dependently reversed damage-associated molecular patterns and inflammatory factor upregulation. Mechanically, our "disease gene-drug target" network analysis indicated that the NCOA4-HMGB1-GSK3B-AQPs axis, implicated in ferroptosis and aquaporin dysregulation, may be potentially served as a target of JTF against OA. Accordingly, JTF mitigated NCOA4, HMGB1, and GSK3B expression, oxidative stress, and iron metabolism aberrations in OA rats. Furthermore, JTF treatment significantly attenuated the aberrant upregulation of AQP1, AQP3, and AQP4 proteins observed in cartilage tissues of OA rats. ConclusionOur data reveal for the first time that JTF may exert cartilage protective and anti-edema effects in osteoarthritis therapy by inhibiting NCOA4-HMGB1-driven ferroptosis and aquaporin dysregulation.

Scutellarein Ameliorated Chondrocyte Inflammation and Osteoarthritis in Rats.

Osteoarthritis (OA) is a degenerative joint disorder characterized by the gradual degradation of joint cartilage and local inflammation. This study aimed to investigate the anti-OA effect of scutellarein (SCU), a single-unit flavonoid compound obtained from Scutellaria barbata D. Don, in rats. The extracted rat chondrocytes were treated with SCU and IL-1β. The chondrocytes were divided into control group, IL-1β group, IL-1β+SCU 50 µmol/L group, and IL-1β+SCU 100 µmol/L group. Morphology of rat chondrocytes was observed by toluidine blue and safranin O staining. CCK-8 method was used to detect the cytotoxicity of SCU. ELISA, qRT-PCR, Western blotting, immunofluorescence, SAβ-gal staining, flow cytometry, and bioinformatics analysis were applied to evaluate the effect of SCU on rat chondrocytes under IL-1β intervention. Additionally, anterior cruciate ligament transection (ACL-T) was used to establish a rat OA model. Histological changes were detected by safranin O/fast green, hematoxylin-eosin (HE) staining, and immunohistochemistry. SCU protected cartilage and exhibited anti-inflammatory effects via multiple mechanisms. Specifically, it could enhance the synthesis of extracellular matrix in cartilage cells and inhibit its degradation. In addition, SCU partially inhibited the nuclear factor kappa-B/mitogen-activated protein kinase (NF-κB/MAPK) pathway, thereby reducing inflammatory cytokine production in the joint cartilage. Furthermore, SCU significantly reduced IL-1β-induced apoptosis and senescence in rat chondrocytes, further highlighting its potential role in OA treatment. In vivo experiments revealed that SCU (at a dose of 50 mg/kg) administered for 2 months could significantly delay the progression of cartilage damage, which was reflected in a lower Osteoarthritis Research Society International (OARSI) score, and reduced expression of matrix metalloproteinase 13 (MMP13) in cartilage. SCU is effective in the therapeutic management of OA and could serve as a potential candidate for future clinical drug therapy for OA.

Anti-Inflammatory, Analgesic, Functional Improvement, and Chondroprotective Effects of Erigeron breviscapus (Vant.) Hand.-Mazz. Extract in Osteoarthritis: An In Vivo and In Vitro Study.

Osteoarthritis (OA) is a degenerative bone disease characterized by inflammation as a primary pathology and currently lacks therapeutic interventions to impede its progression. Erigeron breviscapus (Vant.) Hand.-Mazz. (EB) is an east Asian herbal medicine with a long history of use and a wide range of confirmed efficacy against cardiovascular and central nervous system diseases. The purpose of this study is to evaluate whether EB is worthy of further investigation as a treatment for OA based on anti-inflammatory activity. This study aims to assess the potential of EB as a treatment for OA, focusing on its anti-inflammatory properties. Analgesic effects, functional improvements, and inhibition of cartilage destruction induced by EB were evaluated in acetic acid-induced peripheral pain mice and monosodium iodoacetate-induced OA rat models. Additionally, the anti-inflammatory effect of EB was assessed in serum and cartilage tissue in vivo, as well as in lipopolysaccharide-induced RAW 264.7 cells. EB demonstrated a significant alleviation of pain, functional impairment, and cartilage degradation in OA along with a notable inhibition of pro-inflammatory cytokines, including interleukin-1β, interleukin-6, matrix metalloproteinases 13, and nitric oxide synthase 2, both in vitro and in vivo, in a dose-dependent manner compared to the active control. Accordingly, EB merits further exploration as a potential disease-modifying drug for OA, capable of mitigating the multifaceted pathology of osteoarthritis through its anti-inflammatory properties. Nonetheless, additional validation through a broader experimental design is essential to substantiate the findings of this study.