Osteoarthritis Model Research Articles

Au@CeO2 yolk-shell nanozymes restore mitochondrial dynamics and enhance chondrogenic drug response for cartilage regeneration in osteoarthritis

In osteoarthritic chondrocytes, dysregulation of mitochondrial dynamics due to excessive intracellular reactive oxygen species (ROS) under inflammatory conditions is a significant contributory factor to poor treatment outcomes, because it leads to a reduced cell response to chondrogenic drugs during this state. The aim of this study was to develop a multifunctional Au@CeO2 yolk-shell nanozyme (YSN) as a novel therapeutic nanomaterial and drug delivery system. Under photothermal conditions, Au@CeO2 nanozymes neutralized excessive ROS, enhanced antioxidant capacity, and maintained mitochondrial homeostasis of osteoarthritic chondrocytes, thereby restoring cellular responsiveness to external stimuli. Furthermore, bioactive peptide CK2.1 loaded in YSNs (Au@CeO2-CK2.1) achieved ordered release under photothermal conditions, effectively promoting chondrocyte anabolic activity. In a mice osteoarthritis (OA) model, local Au@CeO2-CK2.1 photothermal therapy effectively enhanced cartilage repair and regeneration in vivo. Mechanically, our research uncovers that decreased chondrogenic drug response is associated with activation of extracellular regulated kinase-1 and -2 (ERK1/2) pathway, and Au@CeO2-CK2.1 YSNs regulates mitochondrial dynamics through inhibiting ERK1/2 and dynamin-1-like protein (DRP1) phosphorylation. The results of this study demonstrated an effective therapeutic strategy that rescued chondrogenic drug response in osteoarthritic chondrocytes, achieving anti-inflammation and cartilage regeneration.

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.

The synergistic anti-nociceptive effects of nefopam and gabapentinoids in inflammatory, osteoarthritis, and neuropathic pain mouse models

Pain is a common public health problem and remains as an unmet medical need. Currently available analgesics usually have limited efficacy or are accompanied by many adverse side effects. To achieve satisfactory pain relief by multimodal analgesia, new combinations of nefopam and gabapentinoids (pregabalin/gabapentin) were designed and assessed in inflammatory, osteoarthritis and neuropathic pain. Isobolographic analysis was performed to analyze the interactions between nefopam and gabapentinoids in carrageenan-induced inflammatory pain, mono-iodoacetate-induced osteoarthritis pain and paclitaxel-induced peripheral neuropathic pain in mice. The anti-inflammatory effect and motor performance of monotherapy or their combinations were evaluated in the carrageenan-induced inflammatory responses and rotarod test, respectively. Nefopam (1, 3, 5, 10, 30 mg/kg, p.o.), pregabalin (3, 6, 12, 24 mg/kg, p.o.) or gabapentin (25, 50, 75, 100 mg/kg, p.o.) dose-dependently reversed mechanical allodynia in three pain models. Isobolographic analysis indicated that the combinations of nefopam and gabapentinoids exerted synergistic anti-nociceptive effects in inflammatory, osteoarthritis, and neuropathic pain mouse models, as evidenced by the experimental ED50 (median effective dose) falling below the predicted additive line. Moreover, the combination of nefopam–pregabalin/gabapentin alleviated carrageenan-induced inflammation and edema, and also prevented gabapentinoids-related sedation or ataxia by lowering their effective doses. Collectively, the co-administration of nefopam and gabapentinoids showed synergistic analgesic effects and may result in improved therapeutic benefits for treating pain.

Automatic grading of knee osteoarthritis with a plain radiograph radiomics model: combining anteroposterior and lateral images

ObjectivesTo establish a radiomics-based automatic grading model for knee osteoarthritis (OA) and evaluate the influence of different body positions on the model’s effectiveness.Materials and methodsPlain radiographs of a total of 473 pairs of knee joints from 473 patients (May 2020 to July 2021) were retrospectively analyzed. Each knee joint included anteroposterior (AP) and lateral (LAT) images which were randomly assigned to the training cohort and the testing cohort at a ratio of 7:3. First, an assessment of knee OA severity was done by two independent radiologists with Kallgren–Lawrence grading scale. Then, another two radiologists independently delineated the region of interest for radiomic feature extraction and selection. The radiomic classification features were dimensionally reduced and a machine model was conducted using logistic regression (LR). Finally, the classification efficiency of the model was evaluated using receiver operating characteristic curves and the area under the curve (AUC).ResultsThe AUC (macro/micro) of the model using a combination of AP and LAT (AP&LAT) images were 0.772/0.778, 0.818/0.799, and 0.864/0.879, respectively. The radiomic features from the combined images achieved better classification performance than the individual position image (p < 0.05). The overall accuracy of the radiomic model with AP&LAT images was 0.727 compared to 0.712 and 0.417 for radiologists with 4 years and 2 years of musculoskeletal diagnostic experience.ConclusionsA radiomic model constructed by combining the AP&LAT images of the knee joint can better grade knee OA and assist clinicians in accurate diagnosis and treatment.Critical relevance statementA radiomic model based on plain radiographs accurately grades knee OA severity. By utilizing the LR classifier and combining AP&LAT images, it improves accuracy and consistency in grading, aiding clinical decision-making, and treatment planning.Key PointsRadiomic model performed more accurately in K/L grading of knee OA than junior radiologists.Radiomic features from the combined images achieved better classification performance than the individual position image.A radiomic model can improve the grading of knee OA and assist in diagnosis and treatment.Graphical

Disease-Modifying Effects of Lenvatinib, a Multiple Receptor Tyrosine Kinase Inhibitor, on Posttraumatic Osteoarthritis of the Knee.

Angiogenesis and vascular endothelial growth factor (VEGF) are involved in osteoarthritis (OA). We previously reported the inhibitory effect of bevacizumab in a rabbit model of OA. In the current study, we investigated the effects of lenvatinib, an angiogenesis inhibitor targeting the VEGF and fibroblast growth factor receptors, on synovitis, osteophyte formation, and cartilage degeneration in a rabbit OA model. Posttraumatic OA was induced by anterior cruciate ligament transection (ACLT) on one knee of each rabbit. Rabbits were placed into four groups according to the following lenvatinib doses: untreated control (n = 12), L0.3: 0.3 mg/kg/day (n = 15), L1.0: 1.0 mg/kg/day (n = 14), and L3.0: 3.0 mg/kg/day (n = 13) groups. We evaluated limb pain using the weight distribution ratio measured with an incapacitance tester, macroscopic osteophyte formation, and femoral condyle synovium and cartilage histology. For cartilage evaluation, the following distal sites of the femur were evaluated separately: femoral-tibial (FT), femoral-patellar (FP), and femoral corner (between FP and FT). The weight distribution ratio at 12 weeks after surgery was higher in the L0.3 and L1.0 groups than in the control group. Osteophyte formation and synovitis scores were significantly lower in the L0.3, L1.0, and L3.0 groups than in the control group. The Osteoarthritis Research Society International scores of the FT, corner, and FP sites in the L0.3 group were lower than in the control group. The cartilage thickness ratio at the FT and corner sites was significantly lower in the L0.3 group than in the control group. Krenn's grading system of cartilage synovitis showed that all lenvatinib-administered groups had significantly lower scores than the control group. MMP3 expression level in cartilage tissue was significantly lower in the L3.0 group compared with the other three groups. ADAMTS5 expression was lower in the L3.0 group compared with the control and L0.3 groups. Oral administration of lenvatinib inhibited synovitis, osteophyte formation, and cartilage degeneration and reduced pain in a rabbit ACLT model. Lenvatinib is an oral VEGF inhibitor that is easier to administer than other VEGF inhibitors and may have potential as a treatment of posttraumatic OA.

Acacetin targets STING to alleviate the destabilization of the medial meniscus-induced osteoarthritis in mice.

Osteoarthritis (OA) is a common joint disorder affecting about 7% of the global population, primarily characterized by the gradual loss of articular cartilage. This degeneration results from local inflammation, matrix depletion, and direct cartilage damage. A critical element in this process is the activation of the stimulator of the interferon genes (STING) pathway. Emerging evidence highlights its potential as a therapeutic target, with natural products showing promise as inhibitors. Our study centers on Acacetin, a basic unit of polyketides known for its anti-inflammatory properties. Prior research has highlighted its potential interaction with STING based on the structure. Thus, this study aimed to assess the effectiveness of Acacetin as a STING inhibitor and its protective role against OA. In vitro experiments showed that Acacetin pretreatment not only mitigated interleukin-1β (IL-1β)-induced cytotoxicity but also decreased the inflammatory response and degeneration in chondrocytes stimulated IL-1β. In vivo studies revealed that Acacetin administration significantly reduced articular cartilage destruction, abnormal bone remodeling, and osteophyte formation in a model of OA induced by destabilization of the medial meniscus (DMM). Mechanistically, Acacetin was found to interact directly with STING, and inhibit IL-1β-induced activation of STING, along with the subsequent phosphorylation of the TBK1/NF-κB pathway in chondrocytes. In conclusion, our findings establish Acacetin as an effective inhibitor of STING that protects chondrocytes from IL-1β-induced damage and slows the progression of OA in mice.

Uncoupling the CRMP2-CaV2.2 interaction reduces pain-like behavior in a preclinical osteoarthritis model.

Osteoarthritis (OA) represents a significant pain challenge globally, as current treatments are limited and come with substantial and adverse side effects. Voltage-gated calcium channels have proved to be pharmacologically effective targets, with multiple FDA-approved CaV2.2 modulators available for the treatment of pain. Although effective, drugs targeting CaV2.2 are complicated by the same obstacles facing other pain therapeutics-invasive routes of administration, narrow therapeutic windows, side effects, and addiction potential. We have identified a key regulator of CaV2.2 channels, collapsing response mediator protein 2 (CRMP2), that allows us to indirectly regulate CaV2.2 expression and function. We developed a peptidomimetic modulator of CRMP2, CBD3063, that effectively reverses neuropathic and inflammatory pain without negative side effects by reducing membrane expression of CaV2.2. Using a rodent model of OA, we demonstrate the intraperitoneal administration of CBD3063 alleviates both evoked and non-evoked behavioral hallmarks of OA pain. Further, we reveal that CBD3063 reduces OA-induced increased neural activity in the parabrachial nucleus, a key supraspinal site modulating the pain experience. Together, these studies suggest CBD3063 is an effective analgesic for OA pain.

Sappanone a alleviates osteoarthritis progression by inhibiting chondrocyte ferroptosis via activating the SIRT1/Nrf2 signaling pathway.

Osteoarthritis (OA) is a common degenerative joint disease that cause pain and disability in adults. Chondrocyte ferroptosis is found to be involved in OA progression. Sappanone A has been found as an anti-inflammatory and antioxidative agent in several diseases. This study aims to investigate the effects of sappanone A on OA progression and chondrocyte ferroptosis.IL-1β-induced chondrocytes and destabilization of the medial meniscus (DMM)-induced rats were respectively used as the OA model in vitro and in vivo. The effects of sappanone A on inflammation, extracellular matrix (ECM) metabolism, and ferroptosis were determined.Our results showed thatin IL-1β-induced chondrocytes, sappanone A suppressed the production of NO, PGE2, TNF-α, IL-6, iNOS, and COX2. Sappanone A also inhibited the expression of MMP3, MMP13, and ADAMTS5, while increasing collagen II expression. Moreover, sappanone A alleviated cytotoxicity and decreased the levels of intracellular ROS, lipid ROS, MDA, and iron, while increasing GSH levels. Additionally, sappanone A increased the protein expression of SLC7A11 and GPX4. Administration of ferroptosis activator reversed the inhibitory effects of sappanone A on IL-1β-induced inflammation and ECM degradation. More importantly, Sappanone A activated the Nrf2 signaling by targeting SIRT1. The inhibition of sappanone A on ferroptosis was greatly eliminated due to the addition of SIRT1 inhibitor. Furthermore, intra-articular injection of sappanone A mitigated cartilage destruction and ferroptosis in DMM-induced OA rats.In conclusion,sappanone A protects against inflammation and ECM degradation in OA via decreasing chondrocyte ferroptosis by activating the SIRT1/Nrf2 signaling. These findings deepen our understanding of chondrocyte ferroptosis in OA and highlight the therapeutic potential of sappanone A for OA.

Establishment of a Posttraumatic Osteoarthritis Model in Mice Induced by Noninvasive Anterior Cruciate Ligament Tear

Background: Animal models that use open surgical transection of the anterior cruciate ligament (ACL) do not accurately simulate the clinical condition regarding the pivot-shift mechanism and the associated inflammatory response that occurs before reconstruction. Purpose/Hypothesis: The purpose was to characterize a reproducible manual, nonsurgical method to mimic an isolated ACL tear in a clinically relevant model and to evaluate the development of progressive posttraumatic osteoarthritis due to ACL injury. It was hypothesized that the ACL could be reproducibly torn with minimal damage to other ligaments and that there would be progressive development of degenerative joint disease after ACL injury. Study Design: Controlled laboratory study. Methods: A total of 37 mice (strain C57BL/6) were used to compare the manual procedure with sham surgery (sham group; n = 10) and with the established surgical ACL transection (ACLT) procedure (surgical group; n = 27). In the sham group, a closed manual procedure was performed on the right knee and sham surgery on the left knee. In the surgical group, the closed manual procedure was performed on the right knee and surgical ACLT on the left knee. Dissection using India ink, histological assessment with safranin O and hematoxylin-eosin staining, radiological evaluation through radiographs and microfocus computed tomography scans, and gait analyses were performed to assess cartilage/ligament status. Osteoarthritis Research Society International (OARSI) and synovitis scores, anterior tibial translation, range of motion, bone microstructure, osteophyte volume, and pain were assessed at 2, 4, and 8 weeks postoperatively. Results: The manual procedure successfully resulted in an ACL rupture and associated meniscal injury. The posterior cruciate, lateral collateral, and medial collateral ligaments were intact in all dissected knees. Two weeks after ACL tear, the surgical group showed a significantly higher synovitis score, whereas 8 weeks after ACL tear, the manual group showed a significantly higher volume of osteophytes. No significant differences were found between the groups in terms of OARSI score, anterior tibial translation, range of motion, bone microstructure computed tomography values, and stride distance/irregularity. Conclusion: This procedure can be used to create an ACL tear model without causing grossly evident injuries to other ligaments and avoiding the risk of cartilage damage from surgical instruments. Clinical Relevance: This procedure offers a more clinically relevant ACL tear model and facilitates simple, inexpensive, and reproducible development of posttraumatic osteoarthritis.

Mechanism of Huangqin Qingre Chubi Capsules regulating p53/p21 signaling pathway to delay chondrocyte senescence in osteoarthritic rats

This study aims to investigate the mechanism of Huangqin Qingre Chubi Capsules(HQC) in delaying chondrocyte senescence of osteoarthritic(OA) rats by regulating the p53/p21 signaling pathway. Rheumatic fever paralysis models of OA rats were induced based on monosodiun iodoacetate(MIA) combined with external rheumatic fever environmental stimuli and divided into normal(Con) group, OA model(MIA) group, OA model+rheumatic fever stimulation model(MIA-M) group, MIA-M+HQC low-dose(MIA-M+HQC-L) group, medium-dose(MIA-M+HQC-M) group, and high-dose(MIA-M+HQC-H) group, and MIA-M+glucosamine(MIA-M+GS) group. The models were successfully prepared and administered by gavage for 30 d. The pathological changes of cartilage were observed by hematoxylin-eosin(HE) and Senna O solid green(SO) staining. The expression of interleukin(IL)-1β and IL-6 was detected by enzyme-linked immunosorbent assay(ELISA). Flow cytometry(FCM) was used to detect apoptosis and cell cycle. The mRNA expression of MMP13, ADAMTS-5, COLⅡ, and TGF-β was detected by RT-qPCR. The protein expression of p53/p21, p16, Bax, and Bcl-2 was detected by Western blot. The articular cartilage surface of rats in the Con group was smooth, and the tide line was smooth. The cartilage layer of MIA and MIA-M groups was obviously damaged, and the cartilage matrix was reduced. The above conditions were more severe in the MIA-M group. The cartilage surface of the HQC high-dose group and MIA-M+GS group was basically intact with clear delamination. Compared with the MIA-M+HQC-H group, Mankin's score was higher in the HQC low-dose and medium-dose groups, and the change was not obvious in the MIA-M+GS group. Compared with the Con group, the proportion of chondrocytes G_1 was elevated in the MIA and MIA-M groups, and the proportion of the S phase and G_2 phase was significantly decreased. In addition, the apoptosis rate was increased. Compared with MIA-M, HQC groups inhibited apoptosis and promoted cell proliferation in a concentration-dependent manner. Compared with the MIA-M+HQC-H group, the effect was more significant in the HQC high-dose group than in the HQC medium-low dose, while it was not significant in the MIA-M+GS group. Compared with the Con group, IL-1β and IL-6 were elevated in the MIA and MIA-M groups, and mRNA levels of MMP13 and ADAMTS-5 were elevated. p53, p21, p16, and Bax protein were elevated, and mRNA levels of COLⅡ and TGF-β were decreased. Compared with the MIA-M group, IL-1β and IL-6 decreased after drug interventions of HQC and GS, and mRNA levels of MMP13 and ADAMTS-5, as well as protein levels of p53, p21, Bax, and p16 decreased. In addition, Bcl-2 increased. The improvement of these indexes was significantly better in the MIA-M+HQC-H group than in the HQC low-dose and medium-dose groups, and the difference with the MIA-M+GS group was not significant. HQC delayed MIA-induced chondrocyte senescence in OA rats, inhibited inflammatory response and extracellular matrix(ECM) degradation, and its mechanism may be related to the inhibition of the p53/p21 pathway.

Oxidized LDL Accelerates Cartilage Destruction and Inflammatory Chondrocyte Death in Osteoarthritis by Disrupting the TFEB-Regulated Autophagy-Lysosome Pathway.

Osteoarthritis (OA) involves cartilage degeneration, thereby causing inflammation and pain. Cardiovascular diseases, such as dyslipidemia, are risk factors for OA; however, the mechanism is unclear. We investigated the effect of dyslipidemia on the development of OA. Treatment of cartilage cells with low-density lipoprotein (LDL) enhanced abnormal autophagy but suppressed normal autophagy and reduced the activity of transcription factor EB (TFEB), which is important for the function of lysosomes. Treatment of LDL-exposed chondrocytes with rapamycin, which activates TFEB, restored normal autophagy. Also, LDL enhanced the inflammatory death of chondrocytes, an effect reversed by rapamycin. In an animal model of hyperlipidemia-associated OA, dyslipidemia accelerated the development of OA, an effect reversed by treatment with a statin, an anti-dyslipidemia drug, or rapamycin, which activates TFEB. Dyslipidemia reduced the autophagic flux and induced necroptosis in the cartilage tissue of patients with OA. The levels of triglycerides, LDL, and total cholesterol were increased in patients with OA compared to those without OA. The C-reactive protein level of patients with dyslipidemia was higher than that of those without dyslipidemia after total knee replacement arthroplasty. In conclusion, oxidized LDL, an important risk factor of dyslipidemia, inhibited the activity of TFEB and reduced the autophagic flux, thereby inducing necroptosis in chondrocytes.

Removal of the infrapatellar fat pad and associated synovium benefits female guinea pigs in the Dunkin Hartley model of idiopathic osteoarthritis.

Several tissues contribute to the onset and advancement of knee osteoarthritis (OA). One tissue type that is worthy of closer evaluation, particularly in the context of sex, is the infrapatellar fat pad (IFP). We previously demonstrated that removal of the IFP had short-term beneficial effects for a cohort of male Dunkin-Hartley guinea pigs. The present project was designed to elucidate the influence of IFP removal in females of this OA-prone strain. It was hypothesized that resection of the IFP would reduce the development of OA in knees of a rodent model predisposed to the disease. Female guinea pigs (n=16) were acquired at an age of 2.5 months. Surgical removal of the IFP and associated synovium complex (IFP/SC) was executed at 3 months of age. One knee had the IFP/SC resected; a comparable sham surgery was performed on the contralateral knee. All animals were subjected to voluntary enclosure monitoring and dynamic weight-bearing, as well as compulsory treadmill-based gait analysis monthly; baseline data was collected prior to surgery. Guinea pigs were euthanized at 7 months. Knees from eight animals were evaluated via histology, mRNA expression, and immunohistochemistry (IHC); knees from the remaining eight animals were allocated to microcomputed tomography (microCT), biomechanical analyses (whole joint testing and indentation relaxation testing), and atomic absorption spectroscopy (AAS). Fibrous connective tissue (FCT) replaced the IFP/SC. Mobility/gait data indicated that unilateral IFP/SC removal did not affect bilateral hindlimb movement. MicroCT demonstrated that osteophytes were not a significant feature of OA in this sex; however, trabecular thickness (TbTh) in medial femorae decreased in knees containing the FCT. Histopathology scores were predominantly influenced by changes in the lateral tibia, which demonstrated that histologic signs of OA were increased in knees containing the native IFP/SC versus those with the FCT. Similarly, indentation testing demonstrated higher instantaneous and equilibrium moduli in the lateral tibial articular cartilage of control knees with native IFPs. AAS of multiple tissue types associated with the knee revealed that zinc was the major trace element influenced by removal of the IFP/SC. Our data suggest that the IFP/SC is a significant component driving knee OA in female guinea pigs and that resection of this tissue prior to disease has short-term benefits. Specifically, the formation of the FCT in place of the native tissue resulted in decreased cartilage-related OA changes, as demonstrated by reduced Osteoarthritis Research Society International (OARSI) histology scores, as well as changes in transcript, protein, and cartilage indentation analyses. Importantly, this model provides evidence that sex needs to be considered when investigating responses and associated mechanisms seen with this intervention.

Acupotomy ameliorates knee osteoarthritis-related collagen deposition and fibrosis in rabbit skeletal muscle through the TGF-β/Smad pathway

ObjectiveTo investigate the effects of acupotomy on skeletal muscle fibrosis and collagen deposition in a rabbit knee osteoarthritis (KOA) model. MethodsRabbits (n = 18) were randomly divided into control, KOA, and KOA + acupotomy (Apo) groups (n = 6). The rabbits in the KOA and Apo groups were modeled using the modified Videman's method for 6 weeks. After modeling, the Apo group was subjected to acupotomy once a week for 3 weeks on the vastus medialis, vastus lateralis, rectus femoris, biceps femoris, and anserine bursa tendons around the knee. The behavior of all animals was recorded, rectus femoris tissue was obtained, and histomorphological changes were observed using Masson staining and transmission electron microscopy. The expression of transforming growth factor-β1 (TGF-β1), Smad 3, Smad 7, fibrillar collagen types I (Col-I) and III (Col-III) was detected using Western blot and real-time polymerase chain reaction (RT-PCR). ResultsHistological analysis revealed that acupotomy improved the microstructure and reduced the collagen volume fraction of rectus femoris, compared with the KOA group (P = .034). Acupotomy inhibited abnormal collagen deposition by modulating the expression of fibrosis-related proteins and mRNA, thus preventing skeletal muscle fibrosis. Western blot and RT-PCR analysis revealed that in the Apo group, Col-I, and Col-III protein levels were significantly lower than those in the KOA group (both P < .01), same as Col-I and Col-III mRNA levels (P = .0031; P = .0046). Compared with the KOA group, the protein levels of TGF-β1 and Smad 3 were significantly reduced (both P < .01), as were the mRNA levels of TGF-β1 and Smad 3 (P = .0007; P = .0011). Conversely, the levels of protein and mRNA of Smad 7 were significantly higher than that in the KOA group (P < .01; P = .0271). ConclusionAcupotomy could alleviate skeletal muscle fibrosis and delay KOA progress by inhibiting collagen deposition through the TGF-β/Smad pathway in the skeletal muscle of KOA rabbits.

The Nrf2/HO-1 pathway participates in the antiapoptotic and anti-inflammatory effects of platelet-rich plasma in the treatment of osteoarthritis.

We aimed to explore the molecular mechanisms through which platelet-rich plasma (PRP) attenuates osteoarthritis (OA)-induced pain, apoptosis, and inflammation. An in vivo model of OA was established by injuring rats using the anterior cruciate ligament transection method, whereas an in vitro model was generated by exposing chondrocytes to interleukin (IL)-1β. Both models were then treated with PRP. In both the in vivo and in vitro models, OA led to the suppression of the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway, whereas treatment with PRP reactivated this molecular axis. Inhibition of the Nrf2/HO-1 pathway using the Nrf2 inhibitor brusatol or through Nrf2 gene silencing counteracted the effects of PRP in reducing the tenderness and thermal pain thresholds of OA rats. Additionally, PRP reduced the mRNA expression of IL-1β, IL-6, tumor necrosis factor-alpha (TNF-α), and matrix metallopeptidase 13 (MMP-13) and the protein expression of B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X-protein (Bax), and caspase-3. Furthermore, inflammation and apoptosis were induced by brusatol treatment or Nrf2 silencing. Additionally, in the in vitro model, PRP treatment increased the proliferation of chondrocytes and attenuated their inflammatory response and apoptosis, effects that were abrogated by Nrf2 depletion. The Nrf2/HO-1 pathway participates in the PRP-mediated attenuation of OA development by suppressing inflammation and apoptosis.

Screening of MMP-13 Inhibitors Using a GelMA-Alginate Interpenetrating Network Hydrogel-Based Model Mimicking Cytokine-Induced Key Features of Osteoarthritis In Vitro.

Osteoarthritis (OA) is a chronic joint disease characterized by irreversible cartilage degradation. Current clinical treatment options lack effective pharmaceutical interventions targeting the disease's root causes. MMP (matrix metalloproteinase) inhibitors represent a new approach to slowing OA progression by addressing cartilage degradation mechanisms. However, very few drugs within this class are in preclinical or clinical trial phases. Hydrogel-based 3D in vitro models have shown promise as preclinical testing platforms due to their resemblance to native extracellular matrix (ECM), abundant availability, and ease of use. Metalloproteinase-13 (MMP-13) is thought to be a major contributor to the degradation of articular cartilage in OA by aggressively breaking down type II collagen. This study focused on testing MMP-13 inhibitors using a GelMA-alginate hydrogel-based OA model induced by cytokines interleukin-1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α). The results demonstrate a significant inhibition of type II collagen breakdown by measuring C2C concentration using ELISA after treatment with MMP-13 inhibitors. However, inconsistencies in human cartilage explant samples led to inconclusive results. Nonetheless, the study highlights the GelMA-alginate hydrogel-based OA model as an alternative to human-sourced cartilage explants for in vitro drug screening.

A standardized approach to evaluation and reporting of synovial histopathology in two surgically induced murine models of osteoarthritis

ObjectiveSynovial pathology has been linked to osteoarthritis (OA) pain in patients. Microscopic grading systems for synovial changes in human OA have been described, but a standardized approach for murine models of OA is needed. We sought to develop a reproducible approach and set of minimum recommendations for reporting of synovial histopathology in mouse models of OA. MethodsCoronal and sagittal sections from male mouse knee joints subjected to destabilization of medial meniscus (DMM) or partial meniscectomy (PMX) were collected as part of other studies. Stains included Hematoxylin and Eosin (H&E), Toluidine Blue (T-Blue) and Safranin O/Fast Green (Saf-O). Four blinded readers graded pathological features (hyperplasia, cellularity, and fibrosis) at specific anatomic locations. Inter-reader agreement of each feature score was determined. ResultsThere was acceptable to very good agreement when using 3-4 individual readers. After DMM and PMX, expected medial predominant changes in hyperplasia and cellularity were observed, with fibrosis noted at 12 weeks post-PMX. Synovial changes were consistent from section to section in the mid-joint area. When comparing stains, H&E and T-blue resulted in better agreement compared to Saf-O stain. ConclusionsTo account for the pathologic and anatomic variability in synovial pathology and allow for a more standardized evaluation that can be compared across studies, we recommend evaluating a minimum set of 3 pathological features at standardized anatomic areas. Further, we suggest reporting individual feature scores separately before relying on a single summed “synovitis” score. H&E or T-blue are preferred, inter-reader agreement for each feature should be considered.

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.

Inhibition of miR-199b-5p reduces pathological alterations in osteoarthritis by potentially targeting Fzd6 and Gcnt2

Osteoarthritis (OA) is a degenerative disease with a high prevalence in the elderly population, but our understanding of its mechanisms remains incomplete. Analysis of serum exosomal small RNA sequencing data from clinical patients and gene expression data from OA patient serum and cartilage obtained from the GEO database revealed a common dysregulated miRNA, miR-199b-5p. In vitro cell experiments demonstrated that miR-199b-5p inhibits chondrocyte vitality and promotes extracellular matrix degradation. Conversely, inhibition of miR-199b-5p under inflammatory conditions exhibited protective effects against damage. Local viral injection of miR-199b-5p into mice induced a decrease in pain threshold and OA-like changes. In an OA model, inhibition of miR-199b-5p alleviated the pathological progression of OA. Furthermore, bioinformatics analysis and experimental validation identified Gcnt2 and Fzd6 as potential target genes of MiR-199b-5p. Thus, these results indicated that MiR-199b-5p/Gcnt2 and Fzd6 axis might be a novel therapeutic target for the treatment of OA.

Inhibition of miR-199b-5p reduces pathological alterations in osteoarthritis by potentially targeting Fzd6 and Gcnt2.

Osteoarthritis (OA) is a degenerative disease with a high prevalence in the elderly population, but our understanding of its mechanisms remains incomplete. Analysis of serum exosomal small RNA sequencing data from clinical patients and gene expression data from OA patient serum and cartilage obtained from the GEO database revealed a common dysregulated miRNA, miR-199b-5p. In vitro cell experiments demonstrated that miR-199b-5p inhibits chondrocyte vitality and promotes extracellular matrix degradation. Conversely, inhibition of miR-199b-5p under inflammatory conditions exhibited protective effects against damage. Local viral injection of miR-199b-5p into mice induced a decrease in pain threshold and OA-like changes. In an OA model, inhibition of miR-199b-5p alleviated the pathological progression of OA. Furthermore, bioinformatics analysis and experimental validation identified Gcnt2 and Fzd6 as potential target genes of MiR-199b-5p. Thus, these results indicated that MiR-199b-5p/Gcnt2 and Fzd6 axis might be a novel therapeutic target for the treatment of OA.