Ligament Transection Research Articles

Curcumin and Vitamin D Supplement Attenuates Knee Osteoarthritis Progression in ACLT + MMx Rat Model: Effect on Cartilage Protection and Pain Reduction.

Background: Knee osteoarthritis (OA) is a common and debilitating disorder marked by joint degradation, inflammation, and persistent pain. This study examined the possible therapeutic effects of curcumin and vitamin D on OA progression and pain in a rat knee OA model by anterior cruciate ligament transection and meniscectomy (ACLT + MMx). Methods: Male Wistar rats were categorized into five groups: control, curcumin-treated (100 mg/kg/day), vitamin D-treated (25 µg/kg/day), a combination of vitamin D and curcumin, and sham-operated. All supplements were administered orally on a daily basis for 12 weeks. Pain behaviors were assessed, serum biomarkers were measured, and knee histology was examined. Results: Both curcumin and vitamin D independently reduced pain, while the combined group exhibited better analgesic effects. Serum inflammatory cytokines demonstrated a decrease in pro-inflammatory cytokines and an elevation in anti-inflammatory cytokine interleukin-10 (IL-10) in the supplement groups. The antioxidative markers were partially recovered by curcumin and vitamin D supplement. However, the oxidative stress marker Cartilage Oligomeric Matrix Protein (COMP) was significantly reduced. Histology analysis revealed a preservation of joint architecture and cartilage integrity and decreased synovium inflammation in the groups treated with curcumin and vitamin D. Conclusions: Our findings indicate a dual mechanism that encompasses the role of anti-inflammation and antioxidation on knee OA progression and pain reduction, underscoring the potential of these natural chemicals as therapeutic agents for knee OA; curcumin and vitamin D supplement may be added in delaying knee OA progression and associated pain management in clinical patient care.

Danggui niantong decoction attenuates synovial fibrosis through regulating PI3k/AKT signaling pathway.

Danggui Niantong Decoction (DGNTD) is a traditional Chinese medicine compound formula that has been demonstrated to possess efficacy in the treatment of rheumatoid arthritis (RA) and osteoarthritis (OA), as well as for dispelling moisture and relieving pain. As mentioned before, DGNTD is essential for synovial inflammation in RA. The primary features of the OA synovial membrane are low-grade inflammation, hyperplasia with enhanced fibroblast-like synoviocytes (FLS) proliferation, and fibrosis, which can cause pain and stiffness. However, it is still unknown how DGNTD functions in the OA synovium. Clarify the influence of DGNTD on OA synovium and investigate potential mechanisms of action. The principal constituents of DGNTD were detected using liquid chromatography-mass spectrometry (LC-MS) analysis. To evaluate the effect of DGNTD on synovial inflammation and fibrosis, a transforming growth factor beta (TGF-β)-stimulated rat FLS cell model and a rat OA animal model based on anterior cruciate ligament transection (ACLT) and partial medial meniscectomy (MMx) were employed. Our results showed that 322 components were detected using LC-MS. In vivo, DGNTD therapy reduced pain, synovial inflammation, and fibrosis. The therapy significantly reduced levels of pain-related molecules, specifically calcitonin gene-related peptide (CGRP) and inducible nitric oxide synthase (iNOS), as well as fibrotic markers, including alpha smooth muscle actin (α-SMA) and type III collagen alpha-1 (Col3a1), in the synovium. A proteomics study demonstrated that DGNTD decreased the fibrotic protein Col3a1. DGNTD reduced the mRNA expression of pro-inflammatory and fibrotic markers (tumor necrosis factor alpha (TNF-α), interleukin-1 beta(IL-1β), interleukin-6(IL-6), α-SMA, Col3a1and TGF-β) in TGF-β-induced FLS. Furthermore, the Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and validation results revealed that DGNTD inhibits synovial fibrosis via the phosphatidylinositol 3-kinase (PI3K)/protein Kinase B (AKT) signaling pathway. DGNTD partially relieves pain, synovitis, and synovial fibrosis by regulating the PI3K/AKT pathway. These findings provide fresh information about the underlying mechanisms and successful therapy of OA, as well as a theoretical and experimental foundation for the clinical management of OA using DGNTD.

Intra-Articular Administration of Ganglioside Sugars Protects Cartilage from Progressive Degeneration in an Instability OA Rabbit Model.

Osteoarthritis (OA) is a degenerative joint disease that has no cure, and current therapies are intended to minimize pain. There is, therefore, a need for effective pharmacologic agents that reverse or slow the progression of joint damage. We report herein on an investigation of the effects of intra-articular injections of ganglioside sugars on the progression of OA in an experimental rabbit model. Knee OA was induced Japanese in White rabbits by anterior cruciate ligament transection (ACLT). Ganglioside sugars at concentrations of 0.1, 0.3, and 0.9 mg/ml were then intra-articularly injected as a possible treatment for OA. Controls received intra-articular injections of saline. Knees were assessed macroscopically, histologically, and mechanically at 13 weeks after ACLT induction. Macroscopically, knees of the groups that received ganglioside sugars at concentrations of 0.3 and 0.9 mg/ml exhibited milder cartilage degradation compared to the controls. Consistent with these results, histological scores for these knees were significantly higher than the corresponding values for the control knees. Lectin histochemistry staining revealed that the treatment with ganglioside sugars at concentrations of 0.3 and 0.9 mg/ml was associated with a remarkable increase in the levels of GalNAc-positive chondrocytes in cartilage. Coefficient of friction testing also demonstrated that cartilages treated with ganglioside sugars had a lower coefficient of frictions than the values for the control group. Intra-articular injections of ganglioside sugars prevented cartilage degeneration in an OA-instability model. These results highlight the promising therapeutic potential for using ganglioside sugars in the treatment of progressive OA.

Polydatin retards the progression of osteoarthritis by maintaining bone metabolicbalance and inhibiting macrophage polarization.

Polydatin (PD), also known as tiger cane glycoside, is a natural compound extracted from the Japanese knotweed plant, which is often referred to as white resveratrol. It exhibits anti-inflammatory, antioxidant, and anti-apoptotic effects in the treatment of various diseases. However, the potential molecular mechanisms of PD in osteoarthritis have not been clearly elucidated. Anterior cruciate ligament transection (ACLT) surgery was performed to establish an osteoarthritis animal model. Female mice at the age of 12weeks were intraperitoneally injected with different concentrations of PD (20 and 40mg/kg). In vitro models were established by isolating mouse articular chondrocytes, which were subsequently treated with lipopolysaccharide or IL-1β for 24h for subsequent experiments. In addition, different concentrations of PD were administered for 12h. Morphological changes were observed by toluidine blue staining, joint bone metabolism changes were observed by tartrate-resistant acid phosphatase staining, immunohistochemistry was used to observe the expression levels of inflammatory factors and extracellular matrix. MicroCT analysis was conducted to assess changes in the microstructure of subchondral bone trabeculae, and Western blot was performed to measure the expression of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling pathway and markers of M1 polarization in macrophages. PD significantly delays the progression of osteoarthritis induced by ACLT, effectively inhibits IL-1β-induced joint inflammation, bone metabolic remodeling and extracellular matrix degradation. In addition, paeoniflorin markedly suppresses the transmission of the NF-κB signaling pathway and reverses M1 polarization in macrophages induced by IL-1β. Taken together, PD might be a potential therapeutic agent for the prevention and treatment of osteoarthritis.

Alleviating osteoarthritis-induced damage through extracellular vesicles derived from inflammatory chondrocytes.

The role of extracellular vesicles (EVs) derived from inflammatory chondrocytes in EV-based therapy for osteoarthritis (OA) has received little attention. We examined the effects of EVs derived from both normal rat chondrocytes (nEVs) and IL-1β-treated rat chondrocytes (iEVs) on IL-1β-treated rat chondrocytes, macrophages, and osteoblasts, alongside mRNA-seq and miRNA-seq analyses of both them. Additionally, nEVs and iEVs were administered intra-articularly in the joints of rat models subjected to anterior cruciate ligament transection (ACLT), and the morphological alterations across the joints were assessed. These findings indicated that iEVs, compared with nEVs, significantly enhanced collagen II synthesis in IL-1β-treated chondrocytes, accompanied by marked increases in ER stress and autophagy. In comparison to nEVs, iEVs exhibited a greater effect on facilitating M2-type macrophage polarization while simultaneously diminishing M1-type polarization, a process likely mediated by the downregulation of chemotactic cytokines such as Cxcl10, Ccl5, Cxcl9, Cxcl1, and Cxcl11. iEVs exerted a more pronounced influence on the phenotypic characteristics of IL-1β-treated osteoblasts than nEVs. In the ACLT-rat model, iEVs, akin to nEVs, effectively mitigated articular cartilage degradation. However, there was no significant difference in OARSI Scores between the two groups, despite iEVs exerting a greater effect on increasing hyaline cartilage thickness and proteoglycan content. iEVs were superior to nEVs in attenuating synovium inflammation and promoting trabecula formation in the femur subchondral bone. Consequently, iEVs, akin to nEVs, significantly alleviated OA-induced damage. Moreover, iEVs outperformed nEVs in certain aspects, notably in augmenting hyaline cartilage, reducing synovium inflammation, and promoting trabecular formation in the subchondral bone during the early stage of OA.

Antioxidant taurine inhibits chondrocyte ferroptosis through upregulation of OGT/Gpx4 signaling in osteoarthritis induced by anterior cruciate ligament transection.

The aim of this study was to investigate the potential molecular mechanisms by which taurine protects against cartilage degeneration. The anterior cruciate ligament transection (ACLT) surgery was used to construct an animal model of osteoarthritis (OA). Metabolomics was used to identify characteristic metabolites in osteoarthritic chondrocytes. Transcriptomics and metabolomics were used to explore potential mechanisms by which the small molecule metabolite taurine protects against inflammatory chondrocyte damage. Cell transfection and small molecule inhibitors/agonists were used to validate the molecular mechanisms by which taurine protects inflammatory chondrocytes in vitro. Finally, adeno-associated virus and small molecule inhibitors/agonists were used to validate the molecular mechanisms by which taurine protects against cartilage degeneration in vivo. Metabolomic assays identified taurine as a possible key metabolic molecule in the progression of OA. Transcriptomics and metabolomics revealed that O-GlcNAc transferase (OGT)-dependent O-GlcNAcylation and Gpx4-dependent ferroptosis may mediate the inflammatory protective effects of taurine on chondrocytes, which was further confirmed by gain and loss of function in vitro. Subsequently, further experiments indicated that the possible existence of a direct binding site for Gpx4 and OGT proteins, which provides evidence for the presence of O-GlcNAc modification of Gpx4 protein. Finnaly, we demonstrated that Gpx4-dependent ferroptosis and OGT-dependent O-GlcNAcylation may be potential mechanisms by which taurine protects against cartilage degeneration in vivo. Antioxidant taurine inhibits chondrocyte ferroptosis through upregulation of OGT/Gpx4 signaling. Supplementation with taurine, a safe nonessential amino acid, may be a potential therapeutic strategy for OA.

Quercetin attenuates the symptoms of osteoarthritis in vitro and in vivo by suppressing ferroptosis via activation of AMPK/Nrf2/Gpx4 signaling.

Osteoarthritis (OA) is a common joint disorder involving the cartilage and other joint tissues. Quercetin (QCT) serves a protective role in the development of OA. However, to the best of our knowledge, the regulatory mechanisms of QCT in the progression of OA have not yet been fully elucidated. In order to mimic a model of OA in vitro, IL‑1β was used to stimulate chondrocytes. Furthermore, an in vivo animal model of OA was induced by anterior cruciate ligament transection (ACLT). 5‑Ethynyl‑2'‑deoxyuridine assays, TUNEL assays, ELISAs, western blotting and immunohistochemical assays were conducted to assess the chondroprotective properties of QCT in the development of OA. The results revealed that 100 µM QCT significantly promoted the proliferation, reduced the apoptosis and inflammation, and inhibited the extracellular matrix (ECM) degradation in IL‑1β‑stimulated chondrocytes. Additionally, QCT attenuated the IL‑1β‑induced ferroptosis of chondrocytes, as demonstrated by the reduced lipid reactive oxygen species and Fe2+ levels. Conversely, the inhibitory effects of QCT on the apoptosis and inflammatory responses were reversed by the activation of ferroptosis by erastin in IL‑1β‑stimulated chondrocytes. Furthermore, QCT significantly elevated the level of phosphorylated (p‑)5' AMP‑activated protein kinase (AMPK) and the levels of two negative regulators of ferroptosis [nuclear factor erythroid 2‑related factor 2 (Nrf2) and glutathione peroxidase 4 (Gpx4)] in IL‑1β‑stimulated chondrocytes. The AMPK inhibitor compound C notably reversed the promoting effects of QCT on phosphorylated‑AMPK, Nrf2 and Gpx4 expression in IL‑1β‑stimulated chondrocytes. Additionally, QCT markedly ameliorated the destruction and degradation of articular cartilage, and elevated the p‑AMPK, Nrf2 and Gpx4 levels in the mouse model of ACLT‑induced OA. Overall, the present study demonstrated that QCT inhibited the development of OA by suppressing ferroptosis via the activation of the AMPK/Nrf2/Gpx4 signaling pathway. These findings provide novel insights into the regulatory mechanisms of QCT for the treatment of patients with OA.

In vivo impact on rabbit subchondral bone of viscosupplementation with a hyaluronic acid antioxidant conjugate

ObjectiveThis study aimed to assess the effects of an antioxidant-conjugated Hyaluronic Acid (HA), specifically HA-4-aminoresorcinol (HA4AR), on articular cartilage and subchondral bone in osteoarthritis (OA). We conducted a comparative analysis between HA4AR and a commercially available high molecular weight HA formulation in a rabbit model of OA.Materials and methodsEighteen rabbits underwent unilateral anterior cruciate ligament transection (ACLT) and were divided into three groups of six: Saline-group, HA-group, and HA4AR-group, based on the type of intra-articular injection received. Additionally, eight non-operated contralateral knees served as reference points (Contralateral-group). Six weeks post-surgery, iodine-enhanced micro-computed tomography imaging was used to evaluate articular cartilage volume and thickness, and to assess subchondral bone microarchitecture and mineral density.ResultsCartilage thickness in both the HA and HA4AR groups was comparable to that of the Contralateral group. Notably, there was a significant reduction in subchondral bone plate tissue mineral density in the HA-group when compared to both the HA4AR and Saline groups (p < 0.05). However, no significant differences in trabecular subchondral bone microarchitectural parameters and mineral densities were observed between the HA4AR-group and the Saline-group. When compared to the Contralateral, Saline, and HA4AR groups, the HA-group exhibited a marked decrease in subchondral bone plate tissue mineral density (p < 0.05). Additionally, a significant reduction in trabecular bone volume fraction was noted in the HA-group compared to the Contralateral-group (p < 0.05).ConclusionsThe HA-4AR hydrogel demonstrated significant preservation of subchondral bone plate tissue mineral density compared to HA alone, while other bone microarchitectural parameters remained largely unchanged. These findings indicate that HA-4AR may provide enhanced osteoprotective benefits in the treatment of osteoarthritis.

Effectiveness of transfer carpal tunnel ligament transection in patients with the CRPS-like symptoms/irritable carpal tunnel syndrome following upper limb trauma: A case series

Effectiveness of transfer carpal tunnel ligament transection in patients with the CRPS-like symptoms/irritable carpal tunnel syndrome following upper limb trauma: A case series

The Molecular Mechanism Investigation of HBP-A Slows Down Meniscus Hypertrophy and Mineralisation by the Damage Mechanical Model.

HBP-A is the main active component of a traditional Chinese medicine Huaizhen Yanggan Capsule, for the remarkable treatment of knee osteoarthritis (KOA). This study aimed to elucidate the ameliorative effect of HBP-A on meniscus hypertrophy and mineralisation in KOA and the molecular mechanism of its action. An Hartley guinea pig model of KOA that underwent anterior cruciate ligament transection (ACLT) and a model of rat primary meniscus fibrochondrocytes (PMFs) were used to investigate the ameliorative effect of HBP-A on meniscal hypertrophy and calcification and its signal transduction mechanism of action. The results show that Guinea pig's meniscus width, as well as the area of meniscus calcification and meniscus and articular cartilage injury score, were significantly reduced in the HBP-A intervention group compared to the ACLT group. The expression levels of mtrix metalloproteinase 13 (MMP13), runt-related transcription factor 2 (Runx2), Indian hedgehog (Ihh), alkaline phosphatase (ALP), and ankylosis homologue (ANKH) at the protein and gene level significantly decreased in the HBP-A intervention group compared to the ACLT group. Invitro study, apoptosis, hypertrophy, and calcification of rat PMFs after 10% stretch force were significantly improved with HBP-A intervention. Western blot and RT-qPCR showed that hypertrophy, calcification, and p38 MAPK signalling pathway-related markers of PMFs were incredibly depressed in the HBP-A intervention group compared to the 10% stretch force group. In conclusion, HBP-A can slow down meniscus hypertrophy and mineralisation induced by abnormal mechanical loading, and its mechanism of action may be through the p38-MAPK signalling pathway.

Cuprorivaite microspheres inhibit cuproptosis and oxidative stress in osteoarthritis via Wnt/β-catenin pathway

This study aims to evaluate the therapeutic potential of cuprorivaite microspheres for osteoarthritis (OA), in particular, potential molecular mechanisms were investigated. The microspheres were developed from Ca(NO3)2•4H2O, Cu(NO3)2•3H2O, and silica gel, and further therapeutic effects were tested in vitro on mouse primary chondrocytes treated with interleukin-1β (IL-1β) to mimic OA, and in vivo on OA mice induced via anterior cruciate ligament transection (ACLT) surgery. The microspheres were shown to mitigate IL-1β-induced apoptotic, inflammatory, and oxidative stress markers while enhancing cell viability and extracellular matrix (ECM) components in chondrocytes. Moreover, the microspheres ameliorated histopathological damage, reduced inflammatory and oxidative stress markers, and enhanced ECM biomarker levels in OA mice, implicating their role in suppressing cuproptosis and oxidative stress. The aforementioned effects of the cuprorivaite microspheres were demonstrated by using SKL2001, an agonist of the Wnt/β-catenin pathway. The results suggest cuprorivaite microspheres as a promising intervention for OA and cartilage regeneration, highlighting their therapeutic effects on cellular and molecular levels.

Soufeng sanjie formula alleviates osteoarthritis by inhibiting macrophage M1 polarization and modulating intestinal metabolites

Ethnopharmacological relevanceOsteoarthritis (OA) is defined as “bone bi” disease based on clinical symptoms in Chinese medicine. Soufeng sanjie formula (SF) is a traditional formula for treating “bone bi” disease, which consists of Scolopendra (dried body of Scolopendra subspinipes mutilans L. Koch) (0.5 g), Scorpions (dried body of Buthus martensii Karsch) (0.5 g), Astragali radix (dried root of Astragalus membranaceus (Fisch.) Bge) (20 g) and Black soybean seed coats (seed coats of Glycine max (L.) Merr) (30 g), and it can be used to treat rheumatoid arthritis. Nonetheless, the potential of SF to postpone the advancement of OA and its underlying mechanisms remain unexplored. Aim of the studyThis study investigated whether SF could alleviate OA and the underlying mechanisms. Materials and methodsAnterior cruciate ligament transection (ACLT) was performed to establish an OA mice model. Mechanical pain and cold pain were assessed to evaluate changes in pain sensitivity in OA mice. Micro-CT was used to observe the microstructure and quantify the bone morphological parameters of knee joints. Safranin O-fast green staining was used to evaluate cartilage damage, and Osteoarthritis Research Society International (OARSI) scores were calculated. Immunohistochemistry was used to assess the expression of inflammatory factors in the synovium of OA mice following SF administration. Immunofluorescence analyzed the fraction of CD80 and iNOS positive regions in the synovium of knee joints. The effect of SF on macrophage M1 polarization was investigated using flow cytometry, western blot and quantitative PCR (qPCR) in vitro. Untargeted metabolomics was used to identify the differential metabolites associated with OA. ResultsSF-treatment markedly reduced the cartilage damage, lowered the OARSI score and downregulated the pain sensitivity in the OA mice. Secondly, SF decreased the expression of IL-6, IL-1β, and TNF-α in the OA synovium. SF also reduced the percentage of CD80 and iNOS in the synovium of the knee joint after ACLT surgery by immunofluorescence. Thirdly, SF inhibited the protein expression of iNOS and COX-2, decreased the percentage of CD80, and reduced the mRNA levels of IL-6, IL-1β, and TNF-α in BMDM cells. Furthermore, SF inhibited the macrophage M1 polarization-related AKT/NF-κB signaling pathway. Finally, untargeted metabolomics showed that SF effectively reduced the levels of intestinal metabolite 18-hydroxyoleic acid in OA mice. ConclusionOur results suggested that SF reduced pain symptoms and joint inflammation in mice with OA. Furthermore, SF inhibited synovial macrophage M1 polarization and modified the levels of the pro-inflammatory intestinal metabolite 18-hydroxyoleic acid in OA mice. Therefore, SF may be act as a potential Chinese medicine for the treatment of OA.

Effect of Cranial Cruciate Ligament Transection during TPLO on Patellar Desmitis in Dogs with Partial Cranial Cruciate Ligament Rupture.

The aim of this study was to assess the protective effect of transecting a partially ruptured cranial cruciate ligament (CCL) during tibial plateau levelling osteotomy (TPLO) surgery on postoperative patellar ligament thickness (PLT) and shortening. Dogs with partial CCL rupture that underwent a unilateral TPLO were included. The population was divided into two groups: remnant CCL transected (study group) and left in situ (control group). Preoperative and 6-week postoperative measurements of PLT, in three specific locations, and patellar ligament length (PLL) were collected. Risk factors for PLT and shortening were also included. Fifty-two dogs (56 stifles) with partial CCL rupture were retrospectively included. Twenty-nine stifles (51.8%) had the remnant CCL transected (study group) and 27 stifles (48.2%) had the remnant CCL left in situ (control group). Significant differences were found on PLT measurements between pre- and 6-week post-surgery for all three ligament locations with greatest difference at the middle region. Median PLL was significantly shorter 6-week post-surgery for both groups. No significant differences in PLT nor PLL were identified between procedures where the remnant was transected or not. This study did not identify a protective effect of transecting the CCL remnant on PLT or patellar ligament shortening, contrary to other reports within the literature. Further investigation is needed in the form of prospective studies with higher number of cases to understand the clinical implications of patellar ligament thickening and shortening in dogs.

Biomechanical evaluation of the porcine carpus as a potential preclinical animal model for the human carpus

Advancing successful treatments for carpal instabilities of the wrist are hindered due, in part, to limited preclinical animal models. The purpose of this study was to evaluate the forelimb of the Yucatan minipig (YP) as a potential preclinical animal model for the human wrist by quantifying carpal biomechanics in vitro in the intact and after two ligament transection conditions. Porcine wrist biomechanics (n = 12, 5M, 7F) were determined in 28 range of motion (ROM) directions, in pronation-supination, and in volar-dorsal translation using a six-axis robotic musculoskeletal simulator. Testing was implemented in three conditions – intact, and after sequential transection of the radial intermediate ligament (RIL) and the dorsal intercarpal ligament (DIC). Mixed models were employed to examine differences in direction and conditions among male and female specimens. The intact ROM envelope was elliptical in shape and oriented toward ulnar flexion with the largest ROM about 15° from the flexion–extension axis. Transection of RIL and DIC did not alter the ROM envelope orientation, however, subtle increases in ROM were observed in extension and radial deviation following transection of both RIL and DIC. Pronation in neutral was greater than supination in all three test conditions. Volar translation increased subtly in the RIL and DIC condition. This novel study investigated the multidirectional biomechanics of the YP forelimb. ROM in the general directions of extension, radial and ulnar deviation were less than in humans, while flexion was substantially larger. These specific ligament transections had minor effects on the biomechanics of the YP forelimb.

Polydatin protects against articular cartilage degeneration by regulating autophagy mediated by the AMPK/mTOR signaling pathway.

Knee osteoarthritis (KOA) is one of the leading causes of disability. Polydatin has a potential effect on KOA treatment but the therapeutic mechanism is not clear. This study aims to investigate the therapeutic action of polydatin in KOA and its mechanism in activating autophagy via the AMP-activated protein kinase (AMPK)/mTOR signaling pathway. After a KOA rat model was established by anterior cruciate ligament transection surgery, model rats were treated with polydatin 40 mg/kg for 30 days. Subsequently, cartilage tissues were collected, and hematoxylin-eosin (HE), Safranin-O, and TUNEL staining, and western blotting were performed to evaluate the pathological damage and autophagy-related protein expression. Then, human chondrocyte C28/I2 cells were stimulated with lipopolysaccharide (LPS), and the effects of polydatin on C28/I2 cell viability, apoptosis, and autophagy-related protein expression were detected by MTT, Flow Cytometry, and western blot. In addition, an AMPK inhibitor (Dorsomorphin 2HCl) was used to probe the cell proliferation and apoptosis of polydatin-administered C28/I2 cells. Polydatin ameliorated the pathological damage in rat cartilage tissues and inhibited cell apoptosis in KOA rats. Meanwhile, in C28/I2 cells, polydatin promoted viability and reduced apoptosis. In addition, the protein expression of collagen II, LC3II/LC3I, Beclin-1, and p-AMPK/AMPK were upregulated, and p62 and p-mTOR/mTOR were downregulated by polydatin treatment. Interestingly, relative results showed that the protective effect of polydatin in LPS-stimulated-C28/I2 cells was blocked by the AMPK/mTOR inhibitor, dorsomorphin 2HCl. Our research showed that polydatin reduced apoptosis and activated autophagy both in vivo and in vitro by the AMPK/mTOR signaling pathway to protect against KOA, which provided the basis for further investigation into the potential therapeutic impact of polydatin on KOA.

Ononin delays the development of osteoarthritis by down-regulating MAPK and NF-κB pathways in rat models.

Osteoarthritis (OA) is featured as cartilage loss, joint pain and loss of labor, which the inflammatory reaction may play critical roles. Ononin is an isoflavone isolating from medicinal plants and has anti-inflammatory effects. Our study investigated the anti-inflammation response of ononin on OA. Anterior cruciate ligament transection (ACLT)-induced OA operation was used to establish research model, then treated with ononin for 8 weeks. The condition of joint injury was assessed using pathological staining. The concentration of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) in serum were measured by Elisa kit. The expression of collagen II and matrix metalloproteinase 13 (MMP-13) proteins to assess cartilage metabolism level by immunohistochemistry and Western blot. We detected the expression of proteins involved in the MAPK and NF-κB signaling pathways. Finally, we used molecular docking to assess the affinity of ononin for the target proteins ERK1/2, JNK1/2, p38 and p65. Our results confirmed that ononin ameliorated cartilage impairment through histopathological analysis by improving the morphological structures and cartilage tidal lines and decreasing Osteoarthritis Research Society International (OARSI) scores in OA rats. Moreover, ononin inhibited the secretion of above factors in OA rats. Furthermore, ononin has been shown to improve cartilage content levels in OA rats. In addition, ononin inhibited the reactivity of MAPK and NF-κB pathways in OA rats. And molecular docking indicated the ligand molecules could stably bind to the proteins of above receptors. Our results demonstrated that ononin may ameliorate cartilage damage and inflammatory response in OA rats by downgrading MAPK and NF-κB pathways, thus identifying ononin as a potential novel drug to treat OA.

The active ingredient of Evodia rutaecarpa reduces inflammation in knee osteoarthritis rats through blocking calcium influx and NF-κB pathway.

Chronic inflammation significantly contributes to the progression of osteoarthritis (OA), and an anti-inflammatory small molecule derived from medicinal herbs could be a potential drug candidate for OA. Herein, we investigated the function and mechanism of Evodiamine (EAE), the active ingredient from Evodia rutaecarpa, in chondrocytes and macrophages in vitro and in vivo. The cytotoxicity of EAE was determined using an MTT assay. And the anti-inflammatory and anti-extracellular matrix (ECM) degradation effects of EAE were investigated using qRT-PCR, western blot (WB), immunofluorescence (IF). Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES), Fluo-4AM, IF and AutoDock were used to elucidate the molecular mechanisms and signalling pathways of the reducing-inflammatory properties of EAE on chondrocytes in vitro. Moreover, the effect of EAE on macrophage polarization was detected by IF and flow cytometry (FC). Ultimately, we explored the in vivo therapeutic efficacy of EAE in an anterior cruciate ligament transection (ACLT)-induced OA model. The finding demonstrated that EAE blocked the phosphorylation of IKBα and Ca2+ influx, thereby curbing inflammation and ECM degradation. Additionally, EAE can prevent the polarization towards the M1 phenotype. Thus, our findings suggest that EAE has great potential as a therapeutic drug for the treatment of OA.

Resatovir Combined with Glycyrrhizic Acid Ameliorates Osteoarthritis and Enhances Autophagy in Chondrocytes

Background Osteoarthritis (OA) is a chronic disease worldwide. With resatovir usually used as an inhibitor, resatovir and glycyrrhizic acid have several pharmacological activities. Purpose We intend to explore the mechanism underlying resatovir combined with glycyrrhizic acid in OA. Methods After the establishment of an animal model of OA through anterior cruciate ligament transection and destabilization of the medial meniscus, the rats were subjected to intramuscular injection of resatovir combined with glycyrrhizic acid (60 mg/kg) or 5% glucose (60 mg/kg) every day for 4 weeks. During the progress, the rat movement and the bend score of knees were observed through behavioral studies. Additionally, the SKP2 gene expression and toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB)-related signaling pathways were examined, as apoptosis and autophagy were evaluated by flow cytometry. Results With increased inflammatory cells in the model group, treatment with resatovir combined with glycyrrhizic acid significantly decreased the number of inflammatory cells. Meanwhile, the treatment resulted in decreased SKP2 expression in OA cells when hindering the migration of preosteoclast cells. Interestingly, it was observed that the bend score increased over the treatment with resatovir plus glycyrrhizic acid and TIPPI% declined dramatically. Resatovir treatment enhanced autophagy and apoptosis in OA cells and decreased pP65, P65, and LC3 expression. Conclusion Resatovir combined with glycyrrhizic acid can inhibit the inflammatory response through decreasing SKP2 expression and induce autophagy activation in OA cells through TLR4/NF-κB signaling, thereby attenuating OA progression.

Platelet-rich plasma ameliorates cartilage degradation in rat models of osteoarthritis via the OPG/RANKL/RANK system.

Osteoarthritis (OA) is one of the most common degenerative joint diseases in the elderly, which is featured by the degradation of articular cartilage. Recently, platelet-rich plasma (PRP) injection into the affected joint has become one biological therapy for OA treatment. The OPG/RANKL/ RANK signalling has been reported to mediate OA progression. Our study aimed to confirm whether PRP injection retards OA development through the regulation of the OPG/RANKL/RANK system. The OA rat models were induced by medial menisci resection combined with anterior cruciate ligament transection. Four weeks after surgery, OA-induced rats received intra- articular injection with 50 μL PRP once a week for 6 weeks. Rats were euthanised one week after the 6th injection. Rat knee joints were subjected to histopathological examination by haematoxylin- eosin (H&E) and safranin O staining. Osteoprotegerin (OPG), receptor activator of nuclear factor kappa B (RANK), and RANK ligand (RANKL) in the articular cartilage of rats were tested through immunofluorescence staining and western blotting. Serum interleukin-1β (IL-1β) and interleukin-6 (IL-6) levels were measured by enzyme-linked immunosorbent assay (ELISA). Matrix metalloproteinase- 13 (MMP-13), aggrecan, collagen α, IL-1β, IL-6, tumour necrosis factor-alpha (TNF-α), and nuclear factor kappa-B (NF-κB) mRNA and protein expression in rat articular cartilage were examined by real-time quantitative polymerase chain reaction (RT-qPCR) and western blotting, respectively. Intra-articular injections of PRP significantly improved the structural integrity of the articular cartilage and enhanced the synthesis of glycosaminoglycans. PRP reduced MMP-13 protein level but increased aggrecan and collagen α protein levels in articular cartilage of OA rats. OA-induced increase in serum IL-1β, IL-6, and TNF-α concentrations as well as increased MMP-13, and decreased collagen II mRNA levels were reversed by the administration of PRP. OA increased IL-1β, TNF-α, and NF-κB mRNA expression in rat articular cartilage whereas PRP administration ameliorated these changes. Moreover, in the articular tissue of OA-induced rats the increased OPG protein level was further elevated by PRP injections whereas the protein level of RANK did not change. The increase in the protein level of RANKL in OA-induced articular tissue was offset by PRP administration. PRP elevated OPG mRNA expression and the OPG/RANKL mRNA ratio, but reduced RANKL mRNA expression and the RANKL/RANK mRNA ratio in the articular tissue of OA-induced rats. PRP mitigates cartilage degradation and inflammation in experimental knee OA by regulating the OPG/RANKL/RANK signalling system.

An injectable self-lubricating supramolecular polymer hydrogel loaded with platelet lysate to boost osteoarthritis treatment

Globally, osteoarthritis (OA) is the most prevalent joint disease and is characterized by infiltration of M1 macrophages in the synovium, anabolic–catabolic imbalance of the extracellular matrix (ECM), increased articular shear force and overproduction of reactive oxygen species (ROS). Disease-modifying OA drugs are not yet available, and treatments for OA focus solely on reducing pain and inflammation and have limited therapeutic effect. Herein, we developed an injectable self-lubricating poly(N-acryloyl alaninamide) (PNAAA) hydrogel loaded with platelet lysate (PL) (termed “PNAAA@PL”) for treating OA. Tribological and drug release tests revealed suitable lubrication properties and sustained release of bioactive factors in PNAAA@PL. In vitro experiments showed that PNAAA@PL alleviated interleukin-1β (IL-1β)-induced anabolic–catabolic imbalance of chondrocytes and repolarized pro-inflammatory M1 macrophages to the anti-inflammatory M2 phenotype via intracellular ROS scavenging. Additionally, the PNAAA@PL hydrogel enhanced the migratory capacity and chemotaxis ability of stem cells, which are essential for chondrogenesis. In vivo, the functionalized PNAAA@PL hydrogel acted like synovial fluid following intra-articular injection into a rat OA model with anterior cruciate ligament transection, ultimately attenuating cartilage degeneration and synovitis. According to molecular mechanism studies, PNAAA@PL repairs cartilage in the OA model by inhibiting the NF-ĸB pathway. Overall, this self-lubricating PNAAA@PL hydrogel offers a comprehensive strategy for preventing OA progression by engineering a biophysiochemical microenvironment to generate high-quality hyaline cartilage.