Tranexamic acid administered intraarticularly to the knee is safer for the articular cartilage and anterior cruciate ligament compared to intravenous administration: Histological analysis of an experimental rat model.

In this study, the effects of tranexamic acid (TXA) on the knee's articular cartilage, anterior cruciate ligament (ACL), and joint capsule were assessed histologically. There were 15 rats in each of the 3 groups, totaling 45 rats. Intraarticular (IA) saline injections were applied for the first group, IA TXA injections for the second group, and intravenous (IV) TXA injections for the third group. Using samples taken from the knee joint 3 weeks later, the medial/lateral femoral condyle and medial/lateral tibial plateau articular cartilages were evaluated with Osteoarthritis Research Society International (OARSI) scoring, while ACL diameter and joint capsule thickness were analyzed histologically. In comparisons of OARSI scores for the medial/lateral femoral condyle and medial/lateral tibial plateau cartilage regions, the scores obtained for the IV TXA group were significantly higher than those of the IA saline group (P < 0.001, P = 0.001, P = 0.003, P = 0.011). In comparisons of medial/lateral femoral condyle and medial/lateral tibial plateau OARSI scores, the scores obtained for the IV TXA group were again significantly higher than those of the IA TXA group (P < 0.001, P < 0.001, P < 0.001, P = 0.002). When ACL diameters were compared, a significant decrease was observed in the ACL diameters of the IV TXA group compared to the IA saline and IA TXA groups (P < 0.001, P = 0.039). Histologically, IV TXA damages the articular cartilage and ACL more than IA TXA. IA administration of TXA is more protective when the articular cartilage and ACL are preserved.

GDF8 inhibition enhances musculoskeletal recovery and mitigates posttraumatic osteoarthritis following joint injury.

Musculoskeletal disorders contribute substantially to worldwide disability. Anterior cruciate ligament (ACL) tears result in unresolved muscle weakness and posttraumatic osteoarthritis (PTOA). Growth differentiation factor 8 (GDF8) has been implicated in the pathogenesis of musculoskeletal degeneration following ACL injury. We investigated GDF8 levels in ACL-injured human skeletal muscle and serum and tested a humanized monoclonal GDF8 antibody against a placebo in a mouse model of PTOA (surgically induced ACL tear). In patients, muscle GDF8 was predictive of atrophy, weakness, and periarticular bone loss 6 months following surgical ACL reconstruction. In mice, GDF8 antibody administration substantially mitigated muscle atrophy, weakness, and fibrosis. GDF8 antibody treatment rescued the skeletal muscle and articular cartilage transcriptomic response to ACL injury and attenuated PTOA severity and deficits in periarticular bone microarchitecture. Furthermore, GDF8 genetic deletion neutralized musculoskeletal deficits in response to ACL injury. Our findings support an opportunity for rapid targeting of GDF8 to enhance functional musculoskeletal recovery and mitigate the severity of PTOA after injury.

Effects of SKCPT on Osteoarthritis in Beagle Meniscectomy and Cranial Cruciate Ligament Transection Models.

Osteoarthritis (OA) affects >500 million people globally, and this number is expected to increase. OA management primarily focuses on symptom alleviation, using non-steroidal anti-inflammatory drugs, including Celecoxib. However, such medication has serious side effects, emphasizing the need for disease-specific treatment. The meniscectomy and cranial cruciate ligament transection (CCLx)-treated beagle dog was used to investigate the efficacy of a modified-release formulation of SKI306X (SKCPT) from Clematis mandshurica, Prunella vulgaris, and Trichosanthes kirilowii in managing arthritis. SKCPT's anti-inflammatory and analgesic properties have been assessed via stifle circumference, gait, incapacitance, histopathology, and ELISA tests. The different SKCPT concentrations and formulations also affected the outcome. SKCPT improved the gait, histopathological, and ELISA OA assessment parameters compared to the control group. Pro-inflammatory cytokines and matrix metalloproteinases were significantly lower in the SKCPT-treated groups than in the control group. This study found that SKCPT reduces arthritic lesions and improves abnormal gait. The 300 mg modified-release formulation was more efficacious than others, suggesting a promising approach for managing OA symptoms and addressing disease pathogenesis. A high active ingredient level and a release pattern make this formulation effective for twice-daily arthritis treatment.

Early zoledronate treatment inhibits subchondral bone microstructural changes in skeletally-mature, ACL-transected canine knees.

Anterior cruciate ligament (ACL) tear leads to post-traumatic osteoarthritis (PTOA), a significant clinical burden worldwide that currently has no cure. Recent studies suggest a role of subchondral bone adaptations in the development of PTOA. Particularly, microstructural changes in the rod-and-plate microstructure of subchondral bone may precede and contribute to OA progression. In this study, we quantified microstructural changes in subchondral trabecular rods and plates after ACL-transection for the first time in the well-established preclinical canine model of PTOA and investigated the therapeutic potentials of a bisphosphonate (zoledronate) and NSAID treatment (meloxicam). Unilateral hindlimb ACL transection was performed on skeletally-mature (2-year-old, N = 20) and juvenile (10-month-old, N = 20) male beagles. Animals were assigned to 4 groups (N = 5): ACLT, un-operated control, ACLT with zoledronate, and ACLT with meloxicam treatment. Subchondral bone microstructure was evaluated by micro-computed tomography and cartilage integrity was evaluated histologically. We found that ACL-induced subchondral bone changes depended on skeletal maturity of animals. In mature animals, significant loss of trabecular plates that resulted in reduced PR ratio occurred at Month 1 and persisted until Month 8. Zoledronate treatment prevented trabecular plate loss while meloxicam treatment did not. Whether cartilage degeneration is also attenuated warrants further investigation. In juvenile animals that have not reached skeletal maturity, transient changes in trabecular plate and rod microstructure occurred at Month 3 but not Month 9. Neither zoledronate nor meloxicam treatment attenuated bone microstructural changes or cartilage damages. Findings from this study suggest that early inhibition of bone resorption by bisphosphonate after injury may be a promising therapeutic approach to prevent alterations in subchondral bone microstructure associated with PTOA. Our results further demonstrate that pathogenesis of PTOA may differ between adolescent and adult patients and therefore require distinct management strategies.

Evaluation of Experimental and Clinical Efficacy on Surgical Debridement and Systemic Antibiotics Treatment for Early Knee Infection after Anterior Cruciate Ligament Reconstruction.

Deep knee infection (DKI) after anterior cruciate ligament reconstruction (ACLR) is rare and challenging. The optimal treatment strategy for infection after ACLR remains controversial. This study aimed to investigate the optimal treatment for early infection after ACLR surgery. Rats with unilateral ACLR were injected with 3.0 × 105 colony forming units (CFU) of Staphylococcus aureus in the knee joint for 7 days. Next, with surgical debridement (SD) and/or 21 days of antimicrobial (systemic vancomycin and oral rifampicin [SVR]) therapy, rats were euthanatized and samples harvested. We evaluated signs of infection by general postoperative conditions, serum inflammatory markers, microbiological counting, knee radiographs, micro-computed tomography (micro-CT), histologic staining, and scanning electron microscopy (SEM). Clinically, the data from 12 patients who suffered from DKI after ACLR were analyzed retrospectively. The DKI rats treated with SVR showed better outcomes in general postoperative conditions, serum inflammatory markers, microbiological counting, biofilm on the interference screw and graft, radiographic signs of periarticular osseous destruction, and inflammatory reaction in the joint tissues than those with SD treatment, while the DKI rats with SD and SVR administration showed the best outcomes. Rats which received SD and SVR administration had their S. aureus contamination completely eradicated. All patients treated with SD & SVR or SVR alone had effectively controlled knee infections and achieved good knee function outcomes in the 6 months after treatment, but one patient developed more serious knee infections. Therefore, surgical debridement combined with systemic antibiotics treatment could effectively eliminate S. aureus contamination in the DKI rat model and in patients after ACLR without affecting knee function. Treatment with systemic antibiotics could also control early DKI, which would be especially applicable in patients who could not tolerate surgery.

High frequency transcutaneous electrical stimulation in the immediate postoperative period of anterior cruciate ligament reconstruction: a randomized clinical trial / Estimulação elétrica transcutânea de alta frequência no pós operatório imediato de reconstrução do ligamento cruzado anterior: um ensaio clínico randomizado

INTRODUCTION: The anterior cruciate ligament (ACL) is an important structure for knee stability. Transcutaneous electrical nerve stimulation (TENS) is an electrical current applied for significant pain relief. OBJECTIVE: To evaluate the effects of high-frequency TENS on the immediate postoperative period of ACL reconstruction. METHODS: 46 patients in the postoperative period of ACL reconstruction were randomly assigned to a control group (CG=23) and a TENS group (TG=23). Knee range of motion (ROM), pain, muscle strength, and drug intake were assessed before surgery and 24 and 48 hours after surgery. The TENS intervention protocol started in the recovery room, shortly after surgery, and was maintained continuously for the first 48 hours after surgery. RESULTS: The TENS group (TG) significantly controlled the increased level of postoperative pain (p<0.05) and significantly increased flexion ROM (p<0.05). When compared to the Control group (CG), the TENS group had a lower intake of ketoprofen (48.27%), diazepam (256.98%), and dipyrone (121.21%), morphine (320.77%), and tramadol (437.46%). CONCLUSION: Continuous high-frequency TENS significantly reduced pain intensity and significantly improved ROM, muscle strength, and drug intake in the postoperative period of ACL reconstruction.

Improving the symptoms of post-traumatic osteoarthritis by α2-macroglobulin-rich serum.

PURPOSE: Altered joint loading by trauma induces joint degeneration, eventually leading to the generation of post-traumatic osteoarthritis (PTOA). Recent studies have shown that α2-macroglobulin (A2M) inhibits PTOA, induced by anterior cruciate ligament transection (ACLT), pathogenesis by regulating proinflammatory cytokines and matrix metalloproteinases. However, the application of A2M is limited due to high prices. Therefore, the aim of this study is to explore the novel preparation of A2M. MATERIALS AND METHODS: The early change of A2M in synovial fluid and serum was measured by ELISA. Ultra-filtered centrifugation was performed to prepare α2-macroglobulin-rich serum (A2MRS). The bioactivity of A2M in A2MRS was detected by improved Ellis and Gollas-Galvan method. The effects of A2MRS on PTOA were observed using immunohistochemistry, safranine O staining, micro X-ray, fluorescence molecular tomography etc. RESULTS: The concentration of A2M in PTOA group was significantly higher than that in Sham group in synovial fluid on the third day after ACLT in rat PTOA model. On the contrary, a significant downregulation of A2M levels in PTOA group was observed compared to the Sham group in serum at the seventh day after ACLT. Secondly, A2MRS was prepared successfully, and the concentration and bioactivity of A2M in A2MRS was significantly higher than that in serum. Lastly, A2MRS not only reduced notably the production of secondary cartilage ossification, type 10 collagen and matrix metalloproteinase 13, but also increased profoundly the generation of type 2 collagen, aggrecan, and chondrocytes' number. CONCLUSION: Our results indicate that A2MRS has protective effects on PTOA.

Anterior Cruciate Ligament Reconstruction: Is Biological Augmentation Beneficial?

Surgical reconstruction in anterior cruciate ligament (ACL) ruptures has proven to be a highly effective technique that usually provides satisfactory results. However, despite the majority of patients recovering their function after this procedure, ACL reconstruction (ACLR) is still imperfect. To improve these results, various biological augmentation (BA) techniques have been employed mostly in animal models. They include: (1) growth factors (bone morphogenetic protein, epidermal growth factor, granulocyte colony-stimulating factor, basic fibroblast growth factor, transforming growth factor-ß, hepatocyte growth factor, vascular endothelial growth factor, and platelet concentrates such as platelet-rich plasma, fibrin clot, and autologous conditioned serum), (2) mesenchymal stem cells, (3) autologous tissue, (4) various pharmaceuticals (matrix metalloproteinase-inhibitor alpha-2-macroglobulin bisphosphonates), (5) biophysical/environmental methods (hyperbaric oxygen, low-intensity pulsed ultrasound, extracorporeal shockwave therapy), (6) biomaterials (fixation methods, biological coatings, biosynthetic bone substitutes, osteoconductive materials), and (7) gene therapy. All of them have shown good results in experimental studies; however, the clinical studies on BA published so far are highly heterogeneous and have a low degree of evidence. The most widely used technique to date is platelet-rich plasma. My position is that orthopedic surgeons must be very cautious when considering using PRP or other BA methods in ACLR.

Chondroprotective Effects of a Histone Deacetylase Inhibitor, Panobinostat, on Pain Behavior and Cartilage Degradation in Anterior Cruciate Ligament Transection-Induced Experimental Osteoarthritic Rats.

Osteoarthritis (OA) is the most common articular degenerative disease characterized by chronic pain, joint inflammation, and movement limitations, which are significantly influenced by aberrant epigenetic modifications of numerous OA-susceptible genes. Recent studies revealed that both the abnormal activation and differential expression of histone deacetylases (HDACs) might contribute to OA pathogenesis. In this study, we investigated the chondroprotective effects of a marine-derived HDAC inhibitor, panobinostat, on anterior cruciate ligament transection (ACLT)-induced experimental OA rats. The intra-articular administration of 2 or 10 µg of panobinostat (each group, n = 7) per week from the 6th to 17th week attenuates ACLT-induced nociceptive behaviors, including secondary mechanical allodynia and weight-bearing distribution. Histopathological and microcomputed tomography analysis showed that panobinostat significantly prevents cartilage degeneration after ACLT. Moreover, intra-articular panobinostat exerts hypertrophic effects in the chondrocytes of articular cartilage by regulating the protein expressions of HDAC4, HDAC6, HDAC7, runt-domain transcription factor-2, and matrix metalloproteinase-13. The study indicated that HDACs might have different modulations on the chondrocyte phenotype in the early stages of OA development. These results provide new evidence that panobinostat may be a potential therapeutic drug for OA.

Acacetin Suppresses IL-1ß-Induced Expression of Matrix Metalloproteinases in Chondrocytes and Protects against Osteoarthritis in a Mouse Model by Inhibiting NF-κB Signaling Pathways.

Osteoarthritis (OA) is a very common chronic joint dysfunction, and there is currently a poor understanding of its etiology and pathogenesis. Therefore, there are no active disease-modifying drugs currently available for clinical treatment. Several natural compounds have been shown to play a role in inhibiting OA progression. The present study is aimed at investigating the curative effects of acacetin, a natural flavonoid compound, against OA. Our results demonstrated that MMP-1, MMP-3, and MMP-13 were highly expressed in OA specimens. Acacetin inhibited the interleukin-1ß- (IL-1ß-) induced expression of MMP-1, MMP-3, and MMP-13in chondrocytes by blocking nuclear factor-κB (NF-κB) signaling pathways. Furthermore, we found that acacetin suppressed OA progression and inhibited the expression of MMP-1, MMP-3, and MMP-13 in ACLT-induced OA mice. Taken together, our study revealed that acacetin may serve as a potential drug for treating OA.

Inhibition of microRNA-27b-3p relieves osteoarthritis pain via regulation of KDM4B-dependent DLX5.

Osteoarthritis (OA) represents a progressive degenerative disorder that predominantly affects the synovial membranes of joints. Recent studies have highlighted the significant role played by microRNAs (miRNAs) in OA development. The current study aimed to elucidate the underlying modulatory role of miR-27b-3p in the development of OA. The expression of miR-27b-3p in the OA patients and rat models post anterior cruciate ligament transection operation was measured using reverse transcription quantitative polymerase chain reaction, through which overexpressed miR-27b-3p was found in both of the samples. To further explore the miR-27b-3p functions in OA, western blot analysis, enzyme-linked immunosorbent assay, and ß-galactosidase activity assay were conducted with the results showing that knockdown of miR-27b-3p promoted expression of the osteogenic differentiation markers while inhibiting expression of the adipogenic differentiation markers, inflammatory factors, and cellular senescence of bone marrow mesenchymal stem cells (BMSCs). After that, the interactions between miR-27b-3p, lysine Demethylase 4B (KDM4B), and Distal-Less Homeobox 5 (DLX5) identified using dual-luciferase reporter gene assay and ChIP assay revealed that miR-27b-3p inhibited KDM4B and further reduced expression of DLX5. Finally, the paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were assessed in rat models, and increased PWT and PWL were detected after miR-27b-3p silencing. In conclusion, suppression of miR-27b-3p could enhance KDM4B and DLX5 to alleviate OA pain, shedding light on a new potential therapeutic target for OA.

Glycitin Suppresses Cartilage Destruction of Osteoarthritis in Mice.

Osteoarthritis (OA), a chronic joint disease, is characterized by cartilage surface erosion, subchondral bone rebuilding, and formation of osteophytes. To date, the nosogenesis and underlying mechanisms of OA have not yet been elucidated. However, it is widely accepted that TNF-α is a crucial cytokine in the development of OA. Glycitin, a natural isoflavone extracted from legumes, affects physiological reactions and pathological responses. Recently, the anti-inflammatory effect of glycitin has been reported. However, the function of glycitin in cartilage degeneration in OA remains to be investigated. In the current study, primary murine chondrocytes were isolated and stimulated by TNF-α to evaluate the anti-inflammatory effects and protective function of glycitin in chondrocytes. In vivo, the ACLT mouse model, a frequently-used OA model, was used to further examine the therapeutic role of glycitin in cartilage degeneration and inflammation in OA. Consequently, glycitin functions were examined both in vivo and in vitro. Moreover, the underlying mechanism of action of glycitin was investigated and was found to involve the NF-κB signaling pathway. Collectively, this study suggests that glycitin can be potentially used for the treatment of joint degenerative diseases, including OA.

Intra-Articular Delivery of Quercetin Using Thermosensitive Hydrogel Attenuate Cartilage Degradation in an Osteoarthritis Rat Model.

OBJECTIVE: Quercetin (Que), a bioflavonoid, is both anti-inflammatory and antioxidative. Que has been used as an oral supplement for osteoarthritis (OA) with inconsistent findings because of its low bioavailability. We encapsulated Que in a mPEG-polypeptide thermogel to prolong its bioactivity. The efficacy of this formulation was evaluated in a posttraumatic OA rat model. DESIGN: Methoxy-poly(ethylene glycol)-l-poly(alanine) (mPEG-PA) polymer was synthesized and characterized in terms of cytotoxicity and release kinetics in vitro. At 12 weeks old, Sprague-Dawley rats underwent anterior cruciate ligament transection (ACLT). At 24 weeks post-operation, rats received either an intra-articular (IA) injection of saline, hydrogel, or hydrogel with Que (50 or 500 µg). Gait analysis was performed at pre-ACLT, pre-treatment, and at 4, 8, and 12 weeks post-treatment. At 12 weeks post-treatment, knee joints were collected for histopathological evaluation. RESULTS: In vitro studies showed that chondrocytes were viable after 72 hours of incubation with mPEG-PA, and the release of Que could be sustained for >28 days. Among all OA rats, the limb idleness index (LII) were significantly increased at 24 weeks post-ACLT. Rats that received hydrogel with Que (50 µg) showed the most reduction in LII at both 4 and 8 weeks post-treatment. The Osteoarthritis Research Society International score of rats received hydrogel with Que (50 µg) was significantly lower than the control group. All rats suffered from low-grade synovitis (Krenn score: 2-4). CONCLUSION: This study suggests that a sustained delivery of Que (50 µg) could provide symptom relief and also delay the progression of OA in the knee.

Dietary Supplements of Shiikuwasha Extract Attenuates Osteoarthritis Progression in Meniscal/ligamentous Injury and Obese Rats.

Osteoarthritis (OA), also called degenerative joint disease, is characterized by joint cartilage loss and is strongly linked to obesity. Medicine to alleviate pain is currently the only treatment. Shiikuwasha extract (SE) has been reported to possess valuable bioactive substances exhibiting anti-inflammatory, antiobesity, and anticancer effects. Research is limited to the use of SE in the treatment of OA and obesity. We performed both anterior cruciate ligament transections and medial meniscectomies to induce OA on Sprague-Dawley rats after 11 weeks of a high fat diet followed by 9 weeks of oral SE administration (300, 600, and 1500 mg/kg). This study showed that SE treatment could reduce weight gain and joint pain. Additionally, SE significantly decreased triglycerides and total cholesterol in plasma of the S1500 group but increased high-density lipoprotein cholesterol in the plasma of the S600 group. Meanwhile, plasma levels of tumor necrosis factor alpha (TNF-α) was significantly reduced in the S1500 groups. Histopathological findings confirmed administration of SE attenuated cartilage degeneration. Immunohistochemistry examination demonstrated that caspase 3 and phospho-Janus kinase 2 (p-JAK2) expression levels on chondrocytes were downregulated by SE treatment. Our findings demonstrate that SE can alleviate OA progression by improving obesity.

Short link N acts as a disease modifying osteoarthritis drug.

Osteoarthritis (OA) is a degenerative joint disease characterised by a progressive degradation of articular cartilage and underlaying bone and is associated with pain and disability. Currently, there is no medical treatment to reverse or even retard OA. Based on our previous reports, where we establish the repair potential of short Link N (sLN) in the intervertebral disc, a cartilage-like tissue, we hypothesise that sLN may hold similar promises in the repair of articular cartilage. This study aimed to determine if sLN, could prevent OA disease progression. Skeletally mature New Zealand white rabbits underwent unilateral anterior cruciate ligament transection (ACLT) of their left femorotibial joints to induce joint degeneration typical of OA. Beginning 3 weeks post-operatively, and every three weeks thereafter for 12 weeks, either saline (1 mL) or sLN (100 µg in 1 mL saline) was injected intraarticularly into the operated knee. Six additional rabbits underwent sham surgery but without ACLT or post-operative injections. The effects on gross joint morphology and cartilage histologic changes were evaluated. In the Saline group, prominent erosion of articular cartilage occurred in both femoral condyle compartments and the lateral compartment of the tibial plateau while, sLN treatment reduced the severity of the cartilage damage in these compartments of the knee showing erosion. Furthermore, statistically significant differences were detected between the joint OA score of the saline and sLN treated groups (p = 0.0118). Therefore, periodic intraarticular injection of sLN is a promising nonsurgical treatment for preventing or retarding OA progression, by reducing cartilage degradation.

Oral shea nut oil triterpene concentrate supplement ameliorates pain and histological assessment of articular cartilage deterioration in an ACLT injured rat knee osteoarthritis model.

Osteoarthritis (OA) is a multifactorial joint disease and a common disabling condition in the elderly population. The associated pain and pathohistological changes in cartilage are common features of OA in both humans and animal models. Shea nut oil extract (SheaFlex75) contains a high triterpenoid concentration and has demonstrated anti-inflammatory and antiarthritic effects in both human and animal studies. In this study, we aim to investigate the potential of SheaFlex75 to prevent articular cartilage deterioration in a rat model of chronic OA progression. By employing anterior cruciate ligament transection (ACLT) with medial meniscectomy (MMx)-induced OA, we found attenuation of both early and chronic onset OA pain and cartilage degeneration in ACLT+MMx rats receiving SheaFlex75 dietary supplementation. Under long-term oral administration, the rats with induced OA presented sustained protection of both pain and OA cartilage integrity compared to the OA-control rats. Moreover, rats subjected to long-term SheaFlex75 ingestion showed normal biochemical profiles (AST, BUN and total cholesterol) and presented relatively lower triglycerides (TGs) and body weights than the OA-control rats, which suggested the safety of prolonged use of this oil extract. Based on the present evidence, preventive management is advised to delay/prevent onset and progression in OA patients. Therefore, we suggest that SheaFlex75 may be an effective management strategy for symptom relief and cartilage protection in patients with both acute and chronic OA.

The selective cathepsin K inhibitor MIV-711 attenuates joint pathology in experimental animal models of osteoarthritis.

BACKGROUND: MIV-711 is a highly potent and selective cathepsin K inhibitor. The current article summarizes the therapeutic effects of MIV-711 on joint pathology in rabbits subjected to anterior cruciate ligament transection (ACLT), and the prophylactic effects on joint pathology in dogs subjected to partial medial meniscectomy, two surgical models of osteoarthritis (OA). METHODS: Starting 1 week after surgery, rabbits were dosed daily via oral gavage with either MIV-711 or vehicle (n = 7/group) for 7 weeks. The four treatment groups were: (1) sham + vehicle; (2) ACLT + vehicle; (3) ACLT + MIV-711, 30 µmol/kg and (4) ACLT + MIV-711, 100 µmol/kg. Subchondral bone and articular cartilage structures were assessed by µCT, histomorphometry, and scoring. Dogs subjected to partial medial meniscectomy received either MIV-711 (30 µmol/kg) or vehicle (n = 15/group) via oral gavage once daily, starting 1 day before meniscectomy, for 28 days. Cartilage degradation was assessed at the macroscopic and microscopic levels. The exposures of MIV-711 were assessed in both studies and biomarkers reflecting bone resorption (HP-1 in rabbits, CTX-I in dogs) and cartilage degradation (CTX-II) were measured. RESULTS: In ACLT rabbits, MIV-711 decreased HP-1 levels by up to 72% (p < 0.001) and CTX-II levels by up to 74% (p < 0.001) compared to ACLT vehicle controls. ACLT surgery significantly reduced the total thickness of the subchondral bone plate and reduced trabecular bone volume in the femur and tibia. These effects were reversed by MIV-711. ACLT resulted in cartilage thickening, which was attenuated by MIV-711. MIV-711 did not affect osteophyte formation or Mankin scores. In dogs, MIV-711 reduced CTX-I and CTX-II levels by 86% (p < 0.001) and 80% (p < 0.001), respectively. Synovial CTX-II levels were reduced by 55-57% (p < 0.001) compared to baseline. MIV-711-treated animals had 25-37% lower macroscopic scores in the femur condyles and 13-33% lower macroscopic scores in the tibial plateaus. CONCLUSIONS: MIV-711 prevents subchondral bone loss and partially attenuates cartilage pathology in two animal models of OA. These beneficial effects of MIV-711 on joint pathology are observed in conjunction with decreases in bone and cartilage biomarkers that have been shown to be clinically attainable in human. The data support the further development of MIV-711 for the treatment of OA.

Parathyroid hormone-(1-34) ameliorated knee osteoarthritis in rats via autophagy.

Anterior cruciate ligament (ACL) tear can lead to osteoarthritis (OA). However, parathyroid hormone (PTH)-(1-34) was found to alleviate OA progression in a papain-induced OA model. Autophagy is a protective mechanism in normal cartilage, and its aging-related loss is linked with chondrocyte death and OA. Thus we examined the roles of autophagy in PTH treatment in OA after ACL transection (ACLT). Thirty-six rats were randomized into three groups: control group, ACLT-induced OA (OA) group, and OA with intra-articular PTH-(1-34) treatment (OA+PTH) group. Weight-bearing and treadmill tests were evaluated. Cartilage matrix was determined by a histological evaluation of glycosaminoglycan (GAG), Osteoarthritis Research Society International (OARSI) score, chondrocyte apoptosis, and immunohistochemistry. Rats in the OA group had significantly decreased weight bearing and running endurance. The histological results indicated that GAG, collagen type II, and chondrocyte autophagy had decreased but that the OARSI score, terminal differentiation markers (collagen type X and Indian hedgehog), and chondrocyte apoptosis had increased in the OA group. Additionally, PTH-(1-34) treatment significantly improved weight bearing and treadmill endurance, preserved GAG and collagen type II, and reduced the OARSI score and terminal differentiation markers. Finally, PTH-(1-34) ameliorated chondrocyte apoptosis by regulating the expression of autophagy-related proteins, through reducing mechanistic target of rapamycin (mTOR) and p62 and enhancing microtubule-associated protein-1 light chain 3 (LC3) and beclin-1. Reconstructive surgery after ACL rupture cannot prevent OA occurrence. Intra-articular PTH-(1-34) treatment can alleviate OA progression after ACLT and histological molecular changes. Possible mechanisms are reducing chondrocyte terminal differentiation and apoptosis, with increasing autophagy. NEW & NOTEWORTHY Anterior cruciate ligament (ACL) tear can lead to osteoarthritis (OA). Intra-articular parathyroid hormone (PTH)-(1-34) significantly improved weight bearing and treadmill endurance, preserved glycosaminoglycan and collagen type II, and reduced Osteoarthritis Research Society International (OARSI) score and terminal differentiation. Finally, PTH-(1-34) ameliorated chondrocyte apoptosis by regulating the expression of autophagy-related proteins, through reducing mechanistic target of rapamycin (mTOR) and p62 and enhancing microtubule-associated protein-1 light chain 3 (LC3) and beclin-1. PTH-(1-34) can alleviate OA progression after ACL transection. Possible mechanisms are reducing chondrocyte terminal differentiation and apoptosis, with increasing autophagy.

Enhancement of Anterior cruciate ligament injury repairing using connective tissue growth factor in a rabbit model.

The study was to evaluate the contribution of connective tissue growth factor (CTGF) to the regeneration of the torn anterior cruciate ligament (ACL) in a rabbit. ACL transection surgeries were performed on both knees of male New Zealand rabbits. Then injury reparation was done as follows: 0.5ml fibrin glue (FG) alone (FG-treated group, n=24 knees) and 0.5ml FG dissolve with 15ng CTGF (CTGF/FG-treated group, n=24 knees). At 2 or 6 weeks after surgery, the ACLs were characterized histologically (n=6 knees) and biomechanically (n=6 knees). The healing effect of the CTGF/FG-treated group was obviously better than that of the FG-treated group, with an increased amount of collagen fibers and fibroblasts in the ligament tissue. After 2 or 6 weeks of healing, CTGF/FG-treated group exhibited significantly higher maximum loads of 8.50±0.58N and 16.35±1.16N, compared with the control group (7.52±0.80N and 13.60±1.35N). And the stiffness of CTGF/FG-treated group at 2 or 6 weeks post-intervention (5.59±1.24N/mm and 11.64±2.21N/mm) was remarkably higher than that the control group (3.74±0.89N/mm and 6.83±2.51N/mm). CTGF could serve as a potentially attractive tool for improving ACL injury treatment by promoting the regeneration of related cells.

Sustained intra-cartilage delivery of low dose dexamethasone using a cationic carrier for treatment of post traumatic osteoarthritis.

Disease-modifying osteoarthritis drugs (DMOADs) should reach their intra-tissue target sites at optimal doses for clinical efficacy. The dense, negatively charged matrix of cartilage poses a major hindrance to the transport of potential therapeutics. In this work, electrostatic interactions were utilised to overcome this challenge and enable higher uptake, full-thickness penetration and enhanced retention of dexamethasone (Dex) inside rabbit cartilage. This was accomplished by using the positively charged glycoprotein avidin as nanocarrier, conjugated to Dex by releasable linkers. Therapeutic effects of a single intra-articular injection of low dose avidin-Dex (0.5 mg Dex) were evaluated in rabbits 3 weeks after anterior cruciate ligament transection (ACLT). Immunostaining confirmed that avidin penetrated the full cartilage thickness and was retained for at least 3 weeks. Avidin-Dex suppressed injury-induced joint swelling and catabolic gene expression to a greater extent than free Dex. It also significantly improved the histological score of cell infiltration and morphogenesis within the periarticular synovium. Micro-computed tomography confirmed the reduced incidence and volume of osteophytes following avidin-Dex treatment. However, neither treatment restored the loss of cartilage stiffness following ACLT, suggesting the need for a combinational therapy with a pro-anabolic factor for enhancing matrix biosynthesis. The avidin dose used caused significant glycosaminoglycan (GAG) loss, suggesting the use of higher Dex : avidin ratios in future formulations, such that the delivered avidin dose could be much less than that shown to affect GAGs. This charge-based delivery system converted cartilage into a drug depot that could also be employed for delivery to nearby synovium, menisci and ligaments, enabling clinical translation of a variety of DMOADs.