Intra-articular injection of the cyclooxygenase-2 inhibitor parecoxib attenuates osteoarthritis progression in anterior cruciate ligament-transected knee in rats: role of excitatory amino acids

Genistein promotes cartilage repair and inhibits synovial inflammatory response after anterior cruciate ligament transection in rats by regulating the Wnt/β-catenin axis

To confirm the protective mechanism of genistein on osteoarthritis (OA). Firstly, we constructed an anterior cruciate ligament transection (ACLT) rat model and administered two doses of genistein via gavage. The effects of the drug on cartilage damage repair and synovitis in OA rats were evaluated through pain-related behavioral assessments, pathological staining, detection of inflammatory factors, and western blot analysis. Secondly, we constructed IL-1-induced chondrocytes and synovial fibroblast models, co-incubated them with genistein, and evaluated the protective effects of genistein on both types of cells through cell apoptosis and cytoskeleton staining. To verify the role of this pathway, we applied the GSK3β inhibitor TWS119 and the Wnt/β-catenin inhibitor XAV939 to ACLT rats and two types of cells to analyze the potential mechanism of genistein's action on OA. Our results confirmed the protective effect of genistein on joint cartilage injury in ACLT rats and its alleviating effect on synovitis. The results of cell experiments showed that genistein can protect IL-1β-induced chondrocytes and synovial fibroblasts, inhibit IL-1β-induced cell apoptosis, increase the fluorescence intensity of F-actin, and inhibit inflammatory response. The results of in vivo and in vitro mechanism studies indicated that TWS119 and XAV939 can attenuate the protective effects of genistein on OA rats and IL-1-induced cell damage. Our research confirmed that genistein may be an effective drug for treating osteoarthritis. Furthermore, we discussed and confirmed that the GSK3β/Wnt/β-catenin axis serves as a downstream signaling pathway of genistein, providing theoretical support for its application.

Multifunctional injectable microspheres for osteoarthritis therapy via spatiotemporally modulating macrophage polarization and inflammation

Local injection of anti-inflammatory drugs for osteoarthritis emerged as a promising administration in the clinic, and sustained-release dosage forms have great potential for future therapeutic applications. Controlling the response of patients only in the acute inflammatory phase is currently the focus of therapeutic interventions. To relieve acute pain in patients and to improve the long-term prognosis effect of osteoarthritis treatment, we designed a two-pronged approach in this research: an injectable double-layer microsphere containing a "nonsteroidal anti-inflammatory drug - macrophage polarizing factor" was constructed. The results indicated that microspheres could regulate the intra-articular environment by inhibiting local inflammatory cytokine production, promoting macrophage polarization to the M2-phenotype, and increasing the expression of cartilage repair factors. Polymers chosen could govern the biocompatibility of microspheres and control the release sequence of the two drugs. Injection of microspheres into the degenerative articular cavity of rats leads to suppressed inflammation and well-promoted cartilage regeneration.

Intra-Articular Lactate Dehydrogenase A Inhibitor Oxamate Reduces Experimental Osteoarthritis and Nociception in Rats via Possible Alteration of Glycolysis-Related Protein Expression in Cartilage Tissue

Osteoarthritis (OA) is the most common form of arthritis and joint disorder worldwide. Metabolic reprogramming of osteoarthritic chondrocytes from oxidative phosphorylation to glycolysis results in the accumulation of lactate from glycolytic metabolite pyruvate by lactate dehydrogenase A (LDHA), leading to cartilage degeneration. In the present study, we investigated the protective effects of the intra-articular administration of oxamate (LDHA inhibitor) against OA development and glycolysis-related protein expression in experimental OA rats. The animals were randomly allocated into four groups: Sham, anterior cruciate ligament transection (ACLT), ACLT + oxamate (0.25 and 2.5 mg/kg). Oxamate-treated groups received an intra-articular injection of oxamate once a week for 5 weeks. Intra-articular oxamate significantly reduced the weight-bearing defects and knee width in ACLT rats. Histopathological analyses showed that oxamate caused significantly less cartilage degeneration in the ACLT rats. Oxamate exerts hypertrophic effects in articular cartilage chondrocytes by inhibiting glucose transporter 1, glucose transporter 3, hexokinase II, pyruvate kinase M2, pyruvate dehydrogenase kinases 1 and 2, pyruvate dehydrogenase kinase 2, and LHDA. Further analysis revealed that oxamate significantly reduced chondrocyte apoptosis in articular cartilage. Oxamate attenuates nociception, inflammation, cartilage degradation, and chondrocyte apoptosis and possibly attenuates glycolysis-related protein expression in ACLT-induced OA rats. The present findings will facilitate future research on LDHA inhibitors in prevention strategies for OA progression.

Effects of inflammation and oxidative stress on postoperative delirium in cardiac surgery

The past decade has witnessed unprecedented medical progress, which has translated into cardiac surgery being increasingly common and safe. However, complications such as postoperative delirium remain a major concern. Although the pathophysiological changes of delirium after cardiac surgery remain poorly understood, it is widely thought that inflammation and oxidative stress may be potential triggers of delirium. The development of delirium following cardiac surgery is associated with perioperative risk factors. Multiple interventions are being explored to prevent and treat delirium. Therefore, research on the potential role of biomarkers in delirium as well as identification of perioperative risk factors and pharmacological interventions are necessary to mitigate the development of delirium.

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.

The effects of a single-dose subacromial injection of a nonsteroidal anti-inflammatory drug in geriatric patients with subacromial impingement syndrome: a randomized double-blind study

Background

As nonsteroidal anti-inflammatory drugs (NSAIDs) and steroids have similar effects, steroids can be avoided to reduce adverse effects. This study aimed to compare the differences in symptom improvement after subacromial injection of steroids or NSAIDs.

Methods

Sixty patients with rotator cuff syndrome for at least 3 months were enrolled and divided into steroid and NSAID groups. The steroid group received a mixture of 1 mL of triamcinolone acetonide (40 mg/mL) and 1 mL of lidocaine hydrochloride 2%, while the NSAID group received a mixture of 1 mL of Ketorolac Tromethamine (30 mg/mL) and 1 mL of lidocaine hydrochloride 2%. The patients were assessed before and at 3, 6, and 12 weeks after the procedure. Shoulder scores from visual analog scale (VAS), American Shoulder and Elbow Surgeons (ASES), and University of California Los Angeles (UCLA) were used for evaluation.

Results

Both groups showed improvements in the clinical outcomes. Overall VAS, ASES, and UCLA scores improved from 6.9, 32.7, and 16.0 before the procedure to 2.0, 1.2, and 1.1; 81.5, 87.6, and 88.5; and 29.7, 31.8, and 32.0 at weeks 3, 6, and 12 weeks after the procedure, respectively. Twenty-six patients (86.7%) in the steroid group and 28 (93.3%) in the NSAID group reported satisfactory treatment outcomes. There were no significant differences in the outcomes between the two groups (p=0.671).

Conclusions

Subacromial injection of NSAIDs for rotator cuff tendinitis with shoulder pain had equivalent outcomes with those of steroid injection at the 12-week follow-up.

Parecoxib alleviates the inflammatory effect of leukocyte-rich platelet-rich plasma in normal rabbit tendons

Background

Platelet-rich plasma (PRP) is widely used to treat tendon injuries. Its therapeutic effect varies depending on the different cell components, and white blood cells (WBCs) may play an important role in this phenomenon. The purpose of this study was to evaluate how PRP with different concentrations of WBCs affect normal rabbit tendon and assess whether non-steroidal anti-inflammatory drugs (NSAIDs) can suppress the catabolic effects of WBCs.

Methods

Sixteen adult New Zealand White rabbits were used. Blood samples were collected from each rabbit, and PRP was extracted following two different protocols to obtain leukocyte-poor PRP (LP-PRP) and leukocyte-rich PRP (LR-PRP). LP-PRP or LR-PRP was injected into the patellar tendon of each rabbit, while normal saline (NS) was injected as control. In LR-PRP + NSAID group, Parecoxib was administered after LR-PRP injection. For each group, 2 rabbits were euthanatized at day 5 and 14. The patellar tendons were collected and stained with hematoxylin and eosin. A semi-quantitative approach was used to assess the inflammatory response and tendon destruction based on the evaluation of the WBCs, vascularization, fiber structure, and fibrosis.

Results

The LR-PRP group exhibited a higher total tendon score than the LP-PRP group at day 5 after PRP injection, but there was no significant difference between the two groups at day 14. For the NSAID group, the tendon score was lower than that of the LR-PRP group both at day 5 and 14.

Conclusion

LR-PRP can promote a higher inflammatory response than LP-PRP in the normal rabbit patellar tendon, and this effect can be suppressed by NSAIDs.

The effects of systemic ozone application and hyperbaric oxygen therapy on knee osteoarthritis: an experimental study in rats

OBJECTIVE

To evaluate the effects of systemic medical ozone (O₃) application and hyperbaric oxygen (HBO) therapy on surgically induced knee osteoarthritis (OA) in a rat model.

MATERIALS AND METHODS

We performed anterior cruciate ligament transection (ACLT) in order to create experimental OA in the right knees of 27 male rats. The left knee joints of all rats were sham-operated without ACLT as the negative control group. The rats were randomly assigned into three groups: (1) control group, which received no treatment; (2) O₃ group, which received intraperitoneal 30 μg medical O₃; (3) HBO group, which received HBO therapy for 60 minutes twice a day. We sacrificed the rats on the tenth week after the operation. We evaluated the degree of OA using Mankin scores.

RESULTS

As a result of histopathological examination, the mean Mankin scores in the right knees with ACLT were 8.17 ± 2.12 in the control group, 6.22 ± 1.56 in the HBO group, and 4.72 ± 1.30 in the O₃ group. The differences between the O₃ group and the HBO group and the O₃ group and the control group were found to be statistically significant (p 0.001, p 0.039, respectively). There was no difference between the HBO group and the control group (p 0.086).

CONCLUSIONS

The results of the present study show that systemic medical O₃ application was more effective than HBO therapy and may reduce development of cartilage damage and prevent OA formation.

Chondroprotective Actions of Selective COX-2 Inhibitors In Vivo: A Systematic Review

Knee osteoarthritis (OA) is a condition mainly characterized by cartilage degradation. Currently, no effective treatment exists to slow down the progression of OA-related cartilage damage. Selective COX-2 inhibitors may, next to their pain killing properties, act chondroprotective in vivo. To determine whether the route of administration is important for the efficacy of the chondroprotective properties of selective COX-2 inhibitors, a systematic review was performed according to the PRISMA guidelines. Studies investigating OA-related cartilage damage of selective COX-2 inhibitors in vivo were included. Nine of the fourteen preclinical studies demonstrated chondroprotective effects of selective COX-2 inhibitors using systemic administration. Five clinical studies were included and, although in general non-randomized, failed to demonstrate chondroprotective actions of oral selective COX-2 inhibitors. All of the four preclinical studies using bolus intra-articular injections demonstrated chondroprotective actions, while one of the three preclinical studies using a slow release system demonstrated chondroprotective actions. Despite the limited evidence in clinical studies that have used the oral administration route, there seems to be a preclinical basis for considering selective COX-2 inhibitors as disease modifying osteoarthritis drugs when used intra-articularly. Intra-articularly injected selective COX-2 inhibitors may hold the potential to provide chondroprotective effects in vivo in clinical studies.

Outcomes of ketorolac versus depomedrol infiltrations for subacromial impingement syndrome: a randomized controlled trial

PURPOSE

Local subacromial infiltration with steroids is a common method of treatment of subacromial impingement syndrome. However, the use of steroids has concerns like tendon rupture, articular cartilage changes and infections. Local NSAIDs infiltration has recently been tried in literature. This study compares the effect of subacromial injections of ketorolac with steroids.

METHODS

A randomized controlled study was planned with 35 patients in each group. Patients in group-1 were infiltrated with subacromial ketorolac (60 mg with 2% lignocaine) and in group-2 with a steroid (methylprednisolone-40 mg with 2% lignocaine). A similar rehabilitation protocol was followed, and clinical outcomes were analyzed using visual analog scale (VAS) for pain and shoulder pain and disability score (SPADI) and range of motion at one-month and three-months follow-up.

RESULTS

Total data of 67 patients were analyzed, as three patients were lost to follow-up. In group 1, mean VAS improved from 7.9 [Formula: see text] 0.95 to 3.19 [Formula: see text] 0.81 (p < 0.001) and SPADI improved from 61.41 [Formula: see text] 11.86 to 28.91 [Formula: see text] 9.06 (p < 0.001) at three months, respectively. In group 2, mean VAS improved from 8.05 [Formula: see text] 0.94 to 2.9 [Formula: see text] 0.64 (p < 0.001) and SPADI improved from 63.45 [Formula: see text] 9.64 to 25.32 [Formula: see text] 6.87 (p < 0.001) at three months, respectively. However, there were no differences in functional outcomes between the groups (p = 0.21 for VAS, p = 0.16 for SPADI).

CONCLUSION

Subacromial ketorolac infiltration has an equivalent outcome as that of steroid infiltration. Ketorolac could be considered as a reasonable alternative to steroids in cases where it is contraindicated.

Comparison of intra-articular injection of parecoxib vs oral administration of celecoxib for the clinical efficacy in the treatment of early knee osteoarthritis

BACKGROUND

Non-steroid anti-inflammatory drugs (NSAIDs) have played a crucial role in the treatment of osteoarthritis, especially in the early stages. However, the cardiovascular risk and adverse gastrointestinal reactions of oral NSAIDs in elderly people cannot be underestimated. Intra-articular injection of NSAIDs may be a new attempt for early knee osteoarthritis treatment. Parecoxib may be a suitable drug for intra-articular injection.

AIM

To observe the clinical efficacy of the intra-articular injection of parecoxib for early knee osteoarthritis.

METHODS

Early knee osteoarthritis patients (n = 110) were retrospectively analyzed. These patients were divided into three groups: Basic treatment + oral glucosamine (group A, n = 37), oral celecoxib + basic treatment + oral glucosamine (group B, n = 37), and intra-articular injection of parecoxib + basic treatment + oral glucosamine (group C, n = 36). Intra-articular injection of parecoxib was performed once every 2 wk at a dose of 40 mg each time, for three times total. The three groups were compared in terms of visual analogue scale (VAS) scores, Hospital for Special Surgery (HSS) scores and patient satisfaction before and after treatment. The levels of inflammatory cytokines in the synovial fluid were detected in the three groups before and after treatment.

RESULTS

All patients were followed up for an average of 15.5 ± 2.7 mo. The clinical efficacy was estimated by VAS and HSS scores at 12 mo after treatment. Inflammatory cytokine levels in the synovial fluid were evaluated at 3 mo after treatment. VAS and HSS scores were significantly improved in each group compared with before (P < 0.001). There were significant differences among the three groups in VAS and HSS scores (P < 0.001). The clinical efficacy of group C was superior to that of groups A and B (P < 0.001), while group B outperformed group A in this respect (P < 0.001). The patient satisfaction was the highest in group C (P < 0.001). After treatment, the levels of tumor necrosis factor α (TNF-α) and interleukin (IL)-6 in the synovial fluid decreased in each group compared with before (P < 0.001), while the levels of IL-10 increased (P < 0.001). The three groups differed significantly in the levels of TNF-a, IL-6 and IL-10 in the synovial fluid after treatment (P < 0.001).

CONCLUSION

For patients with early knee osteoarthritis, intra-articular injection of parecoxib could effectively improve clinical symptoms. This method may be a reliable alternative for early knee osteoarthritis.

The COX-2 inhibitor etoricoxib reduces experimental osteoarthritis and nociception in rats: The roles of TGF-β1 and NGF expressions in chondrocytes

BACKGROUND

Osteoarthritis (OA) is the most common joint disease, especially affecting the knee joint. Etoricoxib, a highly selective cyclooxygenase (COX)-2 inhibitor which can reduce postoperative pain after orthopaedic surgery. The aim of this study was to investigate the effects of oral etoricoxib on the development of OA and to examine concomitant changes in the nociceptive behaviour of rats.

METHOD

OA was induced in wistar rats by anterior cruciate ligament transection (ACLT) of the right knee. The ACLT + etoricoxib groups received 6.7 or 33.3 mg/kg of oral etoricoxib three times a week for 12 consecutive weeks, starting at week 8 after ACLT. Nociceptive behaviours and changes in knee joint width during OA development were analyzed. Histopathological studies were then performed on the cartilage. Immunohistochemical analysis was performed to examine the effect of etoricoxib on the expression of transforming growth factor-beta (TGF-β) and nerve growth factor (NGF) in articular cartilage chondrocytes.

RESULTS

OA rats receiving etoricoxib showed a significantly lower degree of cartilage degeneration than the rats receiving placebo. Nociceptive behaviour studies showed significant improvement in the ACLT + etoricoxib groups compared to that in the ACLT group. Moreover, etoricoxib attenuated NGF expression, but increased TGF-β expression, in OA-affected cartilage.

CONCLUSIONS

Oral etoricoxib in a rat OA model (a) attenuates the development of OA, (b) concomitantly reduces nociception, and (c) modulates chondrocyte metabolism, possibly by inhibiting NGF expression and increasing TGF-β expression.

SIGNIFICANCE

Oral administration of etoricoxib can attenuate the development of OA, with an associated attenuation of nociceptive behaviour in an experimental rat OA model. Moreover, etoricoxib attenuated NGF expression, but enhanced TGF-β expression in OA-affected chondrocytes. These findings may pave the way for further investigations of etoricoxib as a potential therapeutic target for the treatment of the inflammatory component in OA.

Vesicular glutamate transporter isoforms: The essential players in the somatosensory systems

In nervous system, glutamate transmission is crucial for centripetal conveyance and cortical perception of sensory signals of different modalities, which necessitates vesicular glutamate transporters 1-3 (VGLUT 1-3), the three homologous membrane-bound protein isoforms, to load glutamate into the presysnaptic vesicles. These VGLUTs, especially VGLUT1 and VGLUT2, selectively label and define functionally distinct neuronal subpopulations at each relay level of the neural hierarchies comprising spinal and trigeminal sensory systems. In this review, by scrutinizing each structure of the organism's fundamental hierarchies including dorsal root/trigeminal ganglia, spinal dorsal horn/trigeminal sensory nuclear complex, somatosensory thalamic nuclei and primary somatosensory cortex, we summarize and characterize in detail within each relay the neuronal clusters expressing distinct VGLUT protein/transcript isoforms, with respect to their regional distribution features (complementary distribution in some structures), axonal terminations/peripheral innervations and physiological functions. Equally important, the distribution pattern and characteristics of VGLUT1/VGLUT2 axon terminals within these structures are also epitomized. Finally, the correlation of a particular VGLUT isoform and its physiological role, disclosed thus far largely via studying the peripheral receptors, is generalized by referring to reports on global and conditioned VGLUT-knockout mice. Also, researches on VGLUTs relating to future direction are tentatively proposed, such as unveiling the elusive differences between distinct VGLUTs in mechanism and/or pharmacokinetics at ionic/molecular level, and developing VGLUT-based pain killers.

Are non-steroidal anti-inflammatory drug injections an alternative to steroid injections for musculoskeletal pain?: A systematic review

Background

Given the potential side effect profile of steroids, the need for an alternative injectable anti-inflammatory is needed. The purpose of this systematic review was to compare corticosteroid injections with non-steroidal anti-inflammatory drug (NSAID) injections for musculoskeletal pain.

Methods

Reviewers with methodological and content expertise searched three databases: PUBMED, Medline and EMBASE. Two blinded reviewers searched, screened, and evaluated the data quality. Data was abstracted in duplicate. Agreement and descriptive statistics are presented.

Results

Four studies were included. All four studies found no statistically significant differences in improvements on the visual analog scale. The follow-up period within the four studies ranged between 2 weeks and 3 months. No statistically significant differences were demonstrated between the two groups with regards to functional outcomes.

Interpretation

The studies reviewed, while limited in quantity, show that compared with corticosteroids, NSAIDs provide equivalent, if not better, pain relief from the musculoskeletal ailments assessed. Further, there is weak evidence supporting a lower recurrence rate of symptoms with NSAIDs when compared to corticosteroids. There is a need for more long-term high-quality studies on this topic.

Level of evidence

Level II (Systematic review of Level II and III studies).

Randomized controlled trial of intra-articular ketorolac on pain and inflammation after minor arthroscopic knee surgery

BACKGROUND

Ketorolac is an effective non-steroidal anti-inflammatory drug, commonly used with local anaesthetics as part of local infiltration analgesia protocols following orthopaedic surgery. However, systemic uptake and drug action may be the major mechanism after local infiltration. The aims of this project were to study the effects of a small, systemically ineffective dose of ketorolac given intra-articularly for post-operative pain and also to study synovial inflammatory biomarkers. We investigated whether ketorolac affects pro-inflammatory biomarkers in an in vitro model, as well.

METHODS

In this placebo-controlled, blind, randomized study, we analysed intra-articular ketorolac (5 mg) in ambulatory minor knee surgery patients with moderate or severe pain (n = 44). We assessed post-operative pain intensity (n = 44) and analysed microdialysis samples taken from knee synovial tissue every 20 min (n = 34). We also tested cyclooxygenase-independent effects of ketorolac in synovial cells stimulated by prostaglandin E₂ and chondroitin sulphate in vitro.

RESULTS

Intra-articular ketorolac (5 mg) administration did not reduce pain or synovial pro-inflammatory cytokines CXCL1, IL-8, and MCP-1, 0-120 min after knee arthroscopy. Female gender was a risk factor for moderate or severe pain (relative risk 1.45, 95% confidence interval 1.04-2.01). Paradoxically, ketorolac increased the release of CXCL1 and IL-8 in prostaglandin E₂ and chondroitin sulphate-stimulated synovial cells in vitro.

CONCLUSION

Ketorolac prescribed at a low dose intra-articularly does not produce any detectable analgesic effect after minor knee surgery.

Association of anterior cruciate ligament injury with knee osteoarthritis and total knee replacement: A retrospective cohort study from the Taiwan National Health Insurance Database

Objective

This study aimed to support the potential protective role of anterior cruciate ligament (ACL) reconstruction against the development of osteoarthritis (OA).

Methods

In this retrospective cohort study, the long-term results of ACL reconstruction in Taiwan were evaluated based on data from the National Health Insurance Research Database (NHIRD). In total, 8,769 eligible cases were included from 11,921 ACL-injured patients. The cumulative incidence rates of OA and total knee replacement (TKR) were analyzed using the Kaplan-Meier estimator. Cox proportional hazards models were applied to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) of OA.

Results

There was a lower cumulative incidence of OA among ACL-reconstructed patients (271, 33.1%) than among non-reconstructed patients (1,874, 40.3%; p < 0.001). Patients who underwent ACL reconstruction had a lower cumulative incidence of TKR during the follow-up period (0.6%) than the non-reconstructed patients (4.6%, p < 0.001). After adjusting for covariates, ACL-injured patients who underwent reconstruction within one month after ACL injury showed a significantly lower risk of OA than those who never underwent reconstruction (adjusted HR = 0.83, 95% CI = 0.69–0.99).

Conclusions

These results indicate that ACL reconstruction might not provide complete protection from OA development after traumatic knee injury but does yield a lower cumulative incidence of OA development and TKR. Moreover, based on the present study, ACL-injured patients should undergo reconstruction as early as possible (within one month) to lower the risk of OA.

24R,25-Dihydroxyvitamin D3 Protects against Articular Cartilage Damage following Anterior Cruciate Ligament Transection in Male Rats

Osteoarthritis (OA) in humans is associated with low circulating 25-hydroxyvitamin D3 [25(OH)D3]. In vitamin D replete rats, radiolabeled 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] accumulates in articular cartilage following injection of [3H]-25(OH)D3. Previously, we showed that 24R,25(OH)2D3 blocks chondrocyte apoptosis via phospholipase D and p53, suggesting a role for 24R,25(OH)2D3 in maintaining cartilage health. We examined the ability of 24R,25(OH)2D3 to prevent degenerative changes in articular cartilage in an OA-like environment and the potential mechanisms involved. In vitro, rat articular chondrocytes were treated with IL-1β with and without 24R,25(OH)2D3 or 1α,25(OH)2D3. 24R,25(OH)2D3 but not 1α,25(OH)2D3 blocked the effects of IL-1β in a dose-dependent manner, and its effect was partially mediated through the TGF-β1 signaling pathway. In vivo, unilateral anterior cruciate ligament transections were performed in immunocompetent rats followed by intra-articular injections of 24R,25(OH)2D3 or vehicle (t = 0, 7, 14, 21 days). Tissues were harvested on day 28. Joints treated with vehicle had changes typical of OA whereas joints treated with 24R,25(OH)2D3 had less articular cartilage damage and levels of inflammatory mediators. These results indicate that 24R,25(OH)2D3 protects against OA, and suggest that it may be a therapeutic approach for preventing trauma-induced osteoarthritis.

Calcitonin attenuates cartilage degeneration and nociception in an experimental rat model of osteoarthritis: role of TGF-β in chondrocytes

We investigated the role of the calcitonin (Miacalcin) in the progression of osteoarthritis (OA) and in nociceptive behavior in an experimental rat model of OA and osteoporosis. OA was induced by anterior cruciate ligament transection (ACLT) of the right knee and by bilateral ovariectomy (OVX) in Wistar rats. Nociceptive behaviors (secondary mechanical allodynia and weight-bearing distribution of the hind paws) were analyzed prior to surgery and every week, beginning at 12 weeks after surgery, up to 20 weeks. At 20 weeks, histopathological studies were performed on the cartilage of the knee joints. Immunohistochemical analysis was performed to examine the effect of calcitonin on transforming growth factor (TGF)-β1 expression in articular cartilage chondrocytes. Rats subjected to ACLT + OVX surgery showed obvious OA changes in the joints. Animals subjected to ACLT + OVX and treated with calcitonin showed significantly less cartilage degeneration and improved nociceptive tests compared with animals subjected to ACLT + OVX surgeries alone. Moreover, calcitonin increased TGF-β1 expression in chondrocytes in ACLT + OVX-affected cartilage. Subcutaneous injection of calcitonin (1) attenuated the development of OA, (2) concomitantly reduced nociception, and (3) modulated chondrocyte metabolism, possibly by increasing cellular TGF-β1 expression.

Subchondral and epiphyseal bone remodeling following surgical transection and noninvasive rupture of the anterior cruciate ligament as models of post-traumatic osteoarthritis

OBJECTIVE

Animal models are frequently used to study post-traumatic osteoarthritis (PTOA). A common anterior cruciate ligament (ACL) injury model is surgical transection, which may introduce confounding factors from surgery. Noninvasive models could model human injury more closely. The purpose of this study was to compare subchondral and epiphyseal trabecular bone remodeling after surgical transection and noninvasive rupture of the ACL.

METHODS

Thirty-six rats were randomized to an uninjured control, surgical transection (Transection), or noninvasive rupture (Rupture). Animals were randomized to 4 or 10 week time points (n = 6 per group). Micro computed tomography (μCT) imaging was performed with an isotropic voxel size of 12 μm. Subchondral and epiphyseal bone was segmented semi-automatically, and morphometric analysis was performed.

RESULTS

Transection caused a greater decrease in subchondral bone volume fraction (BV/TV) than Rupture in the femur and tibia. Rupture had greater subchondral bone tissue mineral density (TMD) at 4 and 10 weeks in the femur and tibia. Subchondral bone thickness (SCB.Th) was decreased in the femur in Transection only. Epiphyseal BV/TV was decreased in Transection only, and Rupture exhibited increased femoral epiphyseal TMD compared to both Control and Transection. Rupture exhibited greater femoral epiphyseal trabecular thickness (Tb.Th.) compared to Control and Transection at 4 weeks, and both Rupture and Transection had increased femoral epiphyseal Tb.Th. at 10 weeks. Epiphyseal trabecular number (Tb.N) was decreased in both injury groups at both time points. Femoral and tibial epiphyseal structure model index (SMI) increased in both groups.

CONCLUSIONS

The two injury models cause differences in post-injury bone morphometry, and surgical transection may be introducing confounding factors that affect downstream bony remodeling.

Sulfasalazine attenuates ACL transection and medial menisectomy-induced cartilage destruction by inhibition of cystine/glutamate antiporter

We had previously demonstrated that excitatory amino acid glutamate plays a role in the progression and severity of knee osteoarthritis (OA), and early hyaluronic acid injection attenuates the OA progression by attenuation of knee joint glutamate level, which was also related to the cystine/glutamate antiporter system X (system XC-) expression. System XC- uptakes cystine into chondrocytes for glutathione (GSH) synthesis, but the role of system XC- in OA is rarely addressed. Sulfasalazine (SSZ) is a system XC- inhibitor; SSZ was applied intra-articularly to study the function of system XC- in the development of OA in rats subjected to anterior cruciate ligament transection and medial meniscectomy (ACLT + MMx). Moerover, the system XC- activator N-acetylcysteine (NAC) was also applied to verify the role of system XC-. The intra-articular injection of SSZ significantly attenuated knee swelling and cartilage destruction in the knees of ACLT + MMx rats and this effect was blocked by NAC. The results showed that inhibition of system XC- function can attenuate ACLT + MMx-induced cartilage destruction. In the present study, system XC- inhibitor SSZ was shown to reduce glutamate content in synovial fluid and GSH in chondrocytes. It was also showed SSZ could attenuate ACLT + MMx-induced cartilage destruction, and treatment of NAC reversed the protective effect of SSZ.

Randomized controlled studies on the efficacy of antiarthritic agents in inhibiting cartilage degeneration and pain associated with progression of osteoarthritis in the rat

Background

As an initial step in the development of a local therapeutic to treat osteoarthritis (OA), a number of agents were tested for their ability to block activation of inflammation through nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), subchondral bone changes through receptor activator of nuclear factor κB ligand (RANKL)-mediated osteoclastogenesis, and proteolytic degradation through matrix metalloproteinase (MMP)-13 activity. Candidates with low toxicity and predicted efficacy were further examined using either of two widely accepted models of OA joint degeneration in the rat: the monoiodoacetic acid (MIA) model or the medial meniscal tear/medial collateral ligament tear (MMT/MCLT) model.

Methods

Potential therapeutics were assessed for their effects on the activation of nuclear factor (NF)-κB, RANKL-mediated osteoclastogenesis, and MMP-13 activity in vitro using previously established assays. Toxicity was measured using HeLa cells, a synovial cell line, or primary human chondrocytes. Drugs predicted to perform well in vivo were tested either systemically or via intraarticular injection in the MIA or the MMT/MCLT model of OA. Pain behavior was measured by mechanical hyperalgesia using the digital Randall-Selitto test (dRS) or by incapacitance with weight bearing (WB). Joint degeneration was evaluated using micro computed tomography and a comprehensive semiquantitative scoring of cartilage, subchondral bone, and synovial histopathology.

Results

Several agents were effective both in vitro and in vivo. With regard to pain behavior, systemically delivered clonidine was superior in treating MIA-induced changes in WB or dRS, while systemic clonidine, curcumin, tacrolimus, and fluocinolone were all somewhat effective in modifying MMT/MCLT-induced changes in WB. Systemic tacrolimus was the most effective in slowing disease progression as measured by histopathology in the MMT/MCLT model.

Conclusions

All of the agents that demonstrated highest benefit in vivo, excepting clonidine, were found to inhibit MMP-13, NF-κB, and bone matrix remodeling in vitro. The MIA and MMT/MCLT models of OA, previously shown to possess inflammatory characteristics and to display associated pain behavior, were affected to different degrees by the same drugs. Although no therapeutic was remarkable across all measures, the several which showed the most promise in either model merit continued study with alternative dosing and therapeutic strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-0921-5) contains supplementary material, which is available to authorized users.

Changes in Membrane Receptors and Ion Channels as Potential Biomarkers for Osteoarthritis

Osteoarthritis (OA), a degenerative joint condition, is currently difficult to detect early enough for any of the current treatment options to be completely successful. Early diagnosis of this disease could increase the numbers of patients who are able to slow its progression. There are now several diseases where membrane protein biomarkers are used for early diagnosis. The numbers of proteins in the membrane is vast and so it is a rich source of potential biomarkers for OA but we need more knowledge of these before they can be considered practical biomarkers. How are they best measured and are they selective to OA or even certain types of OA? The first step in this process is to identify membrane proteins that change in OA. Here, we summarize several ion channels and receptors that change in OA models and/or OA patients, and may thus be considered candidates as novel membrane biomarkers of OA.

Excitatory amino acid glutamate: role in peripheral nociceptive transduction and inflammation in experimental and clinical osteoarthritis

Although a large proportion of patients with osteoarthritis (OA) show inflammation in their affected joints, the pathological role of inflammation in the development and progression of OA has yet to be clarified. Glutamate is considered an excitatory amino acid (EAA) neurotransmitter in the mammalian central nervous system (CNS). There are cellular membrane glutamate receptors and transporters for signal input modulation and termination as well as vesicular glutamate transporters (VGLUTs) for signal output through exocytotic release. Glutamate been shown to mediate intercellular communications in bone cells in a manner similar to synaptic transmission within the CNS. Glutamate-mediated events may also contribute to the pathogenesis and ongoing processes of peripheral nociceptive transduction and inflammation of experimental arthritis models as well as human arthritic conditions. This review will discuss the differential roles of glutamate signaling and blockade in peripheral neuronal and non-neuronal joint tissues, including bone remodeling systems and their potentials to impact OA-related inflammation and progression. This will serve to identify several potential targets to direct novel therapies for OA. Future studies will further elucidate the role of glutamate in the development and progression of OA, as well as its association with the clinical features of the disease.

Protective effects of tumor necrosis factor-α blockade by adalimumab on articular cartilage and subchondral bone in a rat model of osteoarthritis

We aimed to investigate the effects of an anti-tumor necrosis factor-α antibody (ATNF) on cartilage and subchondral bone in a rat model of osteoarthritis. Twenty-four rats were randomly divided into three groups: sham-operated group (n=8); anterior cruciate ligament transection (ACLT)+normal saline (NS) group (n=8); and ACLT+ATNF group (n=8). The rats in the ACLT+ATNF group received subcutaneous injections of ATNF (20 μg/kg) for 12 weeks, while those in the ACLT+NS group received NS at the same dose for 12 weeks. All rats were euthanized at 12 weeks after surgery and specimens from the affected knees were harvested. Hematoxylin and eosin staining, Masson's trichrome staining, and Mankin score assessment were carried out to evaluate the cartilage status and cartilage matrix degradation. Matrix metalloproteinase (MMP)-13 immunohistochemistry was performed to assess the cartilage molecular metabolism. Bone histomorphometry was used to observe the subchondral trabecular microstructure. Compared with the rats in the ACLT+NS group, histological and Mankin score analyses showed that ATNF treatment reduced the severity of the cartilage lesions and led to a lower Mankin score. Immunohistochemical and histomorphometric analyses revealed that ATNF treatment reduced the ACLT-induced destruction of the subchondral trabecular microstructure, and decreased MMP-13 expression. ATNF treatment may delay degradation of the extracellular matrix via a decrease in MMP-13 expression. ATNF treatment probably protects articular cartilage by improving the structure of the subchondral bone and reducing the degradation of the cartilage matrix.

Hylan G-F 20 attenuates posttraumatic osteoarthritis progression: Association with upregulated expression of the circardian gene NPAS2

AIMS

The study was to examine the effect of Hylan G-F 20 on the progression of posttraumatic osteoarthritis (PTOA) and the expression of the circadian genes neuronal PAS domain protein 2 (NPAS2) and period 2 (Per2).

MAIN METHODS

We used the anterior cruciate ligament transaction and medial menisectomy (ACLT+MMx) model in Wistar rats. The rats were divided into three groups, the sham-operated group, the Hylan G-F 20-treated group, and the saline-treated group. Rats which underwent ACLT + MMx surgery were injected intraarticularly with, respectively, Hylan G-F 20 or saline once a week for 3 consecutive weeks, starting 7days after surgery. The gross morphology and histopathology of the experimental knee joints were evaluated at the end of week 6. Expression of the NPAS2 and Per2 genes was measured by real-time PCR.

KEY FINDINGS

Hylan G-F 20 suppressed the articular cartilage destruction and synovitis compared to the saline-treated group. Compared to the sham-operated group, the Hylan G-F 20-treated group showed significantly upregulated expression of NPAS2 in cartilage (2.53±0.08-fold higher; p<0.05) and a non-significant increase in Per2 expression (2.35±1.26-fold higher p=0.28), while the saline-treated group showed significant downregulation of NPAS2 expression and a non-significant decrease in Per2 expression.

SIGNIFICANCE

Our data suggested that early intraarticular injection of Hylan G-F 20 attenuates the progression of PTOA and significantly upregulates NPAS2 expression. These findings provide a new direction for studying associations between the use of a pharmacological agent, the degenerative process, and circadian gene expression.

Reactive oxygen species induce Cox-2 expression via TAK1 activation in synovial fibroblast cells

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Oxidative stress in the arthritis joint is involved in generating mediators for inflammation.

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Oxidative stress-induced expression of Cox-2 was mediated by MAPKs and NF-κB.

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ROS-induced MAPKs and NF-κB were attenuated by inhibition of MAPKKK TAK1.

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Inhibition of TAK1 activity resulted in reduced expression of Cox-2 and PGE2.

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ROS-induced TAK1 activation and Cox-2 expression was inhibited by antioxidants N-acetyl cysteamine and hyaluronic acid.

Oxidative stress within the arthritis joint has been indicated to be involved in generating mediators for tissue degeneration and inflammation. COX-2 is a mediator in inflammatory action, pain and some catabolic reactions in inflamed tissues. Here, we demonstrated a direct relationship between oxidative stress and Cox-2 expression in the bovine synovial fibroblasts. Furthermore, we elucidated a novel mechanism, in which oxidative stress induced phosphorylation of MAPKs and NF-κB through TAK1 activation and resulted in increased Cox-2 and prostaglandin E2 expression. Finally, we demonstrated that ROS-induced Cox-2 expression was inhibited by supplementation of an antioxidant such as N-acetyl cysteamine and hyaluronic acid in vitro and in vivo. From these results, we conclude that oxidative stress is an important factor for generation of Cox-2 in synovial fibroblasts and thus its neutralization may be an effective strategy in palliative therapy for chronic joint diseases.

Progranulin protects against osteoarthritis through interacting with TNF-α and β-Catenin signalling

OBJECTIVE

Progranulin (PGRN) was previously isolated as an osteoarthritis (OA)-associated growth factor. Additionally, PGRN was found to play a therapeutic role in inflammatory arthritis mice models through antagonising tumour necrosis factor α (TNF-α). This study was aimed at investigating the role of PGRN in degradation of cartilage and progression of OA.

METHODS

Progression of OA was analysed in both spontaneous and surgically induced OA models in wild type and PGRN-deficient mice. Cartilage degradation and OA were evaluated using Safranin O staining, immunohistochemistry and ELISA. Additionally, mRNA expression of degenerative factors and catabolic markers known to be involved in cartilage degeneration in OA were analysed. Furthermore, the anabolic effects and underlying mechanisms of PGRN were investigated by in vitro experiments with primary chondrocytes.

RESULTS

Here, we found that deficiency of PGRN led to spontaneous OA-like phenotype in 'aged' mice. Additionally, PGRN-deficient mice exhibited exaggerated breakdown of cartilage structure and OA progression, while local delivery of recombinant PGRN protein attenuated degradation of cartilage matrix and protected against OA development in surgically induced OA models. Furthermore, PGRN activated extracellular signal-regulated kinases (ERK) 1/2 signalling and elevated the levels of anabolic biomarkers in human chondrocyte, and the protective function of PGRN was mediated mainly through TNF receptor 2. Additionally, PGRN suppressed inflammatory action of TNF-α and inhibited the activation of β-Catenin signalling in cartilage and chondrocytes.

CONCLUSIONS

Collectively, this study provides new insight into the pathogenesis of OA, and also presents PGRN as a potential target for the treatment of joint degenerative diseases, including OA.

Intra-articular injection of the selective cyclooxygenase-2 inhibitor meloxicam (Mobic) reduces experimental osteoarthritis and nociception in rats

OBJECTIVE

To study the effect of intra-articular injection of meloxicam (Mobic) on the development of osteoarthritis (OA) in rats and examine concomitant changes in nociceptive behavior and the expression of mitogen-activated protein kinases (MAPKs) in articular cartilage chondrocytes.

METHODS

OA was induced in Wistar rats by right anterior cruciate ligament transection (ACLT); the left knee was not treated. The OA + meloxicam (1.0 mg) group was injected intra-articularly in the ACLT knee with 1.0 mg of meloxicam once a week for 5 consecutive weeks starting 5 weeks after ACLT. The OA + meloxicam (0.25 mg) group was treated similarly with 0.25 mg meloxicam. The sham group underwent arthrotomy only and received vehicle of 0.1 mL sterile 0.9% saline injections, whereas the naive rats in meloxicam-only groups were treated similarly with 1.0- and 0.25-mg meloxicam. Nociception was measured as secondary mechanical allodynia and hind paw weight-bearing distribution at before (pre-) and 5, 10, 15, and 20 weeks post-ACLT. Histopathology of the cartilage and synovia was examined 20 weeks after ACLT. Immunohistochemical analysis was performed to examine the effect of meloxicam on MAPKs (p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK)) expression in the articular cartilage chondrocytes.

RESULTS

OA rats receiving intra-articular meloxicam treatment showed significantly less cartilage degeneration and synovitis than saline-treated controls. Nociception were improved in the OA + meloxicam groups compared with the OA group. Moreover, meloxicam attenuated p38 and JNK but enhanced ERK expression in OA-affected cartilage.

CONCLUSIONS

Intra-articular injection of meloxicam (1) attenuates the development of OA, (2) concomitantly reduces nociception, and (3) modulates chondrocyte metabolism, possibly through inhibition of cellular p38 and JNK, but enhances ERK expression.

Effects of tibolone on osteoarthritis in ovariectomized rats: association with nociceptive pain behaviour

BACKGROUND

To investigate the role of the synthetic steroid tibolone in the progression of osteoarthritis (OA) and in nociceptive behaviour in an experimental rat model of OA and ovariectomy (OVX)-induced osteoporosis.

METHODS

OA was induced in Wistar rats by anterior cruciate ligament transection (ACLT) of the right knee. Osteoporosis was induced by bilateral OVX. Groups of animals were subjected to ACLT, OVX, sham or OVX + ACLT. In addition, two groups were subjected to OVX + ACLT surgeries and were orally administered 0.1 or 0.5 mg tibolone every other day for 14 consecutive weeks, starting 6 weeks after surgery. Nociceptive behaviours (secondary mechanical allodynia and weight-bearing distribution of the hind paws) were analysed prior to and every 3 weeks after surgery up to 24 weeks. At 24 weeks, histopathological studies were performed on the cartilage and synovial membranes of the knee joints, and bone metabolism was assessed by measuring serum concentrations of calcium, phosphorus and alkaline phosphatase.

RESULTS

Rats undergoing ACLT or OVX + ACLT surgeries showed obvious OA changes in the joints. Animals subjected to ACLT + OVX and treated with tibolone had significantly less cartilage degeneration and synovitis and showed improved nociceptive tests compared with animals undergoing ACLT + OVX surgeries alone. OVX increased the severity of the ACLT-induced OA changes. There was a significant increase in serum alkaline phosphatase in the tibolone-treated ACLT + OVX groups.

CONCLUSIONS

Treatment with tibolone attenuated the development of OA, concomitantly reduced nociception and increased serum alkaline phosphatase in ACLT + OVX rats.

The efficacy of parecoxib on systemic inflammatory response associated with cardiopulmonary bypass during cardiac surgery

AIMS

Cardiopulmonary bypass (CPB) during cardiac surgery is well known to be associated with the development of a systemic inflammatory response. The efficacy of parecoxib in attenuating this systemic inflammatory response is still unknown.

METHODS

Patients undergoing elective mitral valve replacement with CPB were assessed, enrolled and randomly allocated to receive parecoxib (80 mg) or placebo. Blood samples were collected in EDTA vials for measuring serum cytokine concentrations, troponin T, creatinekinase myocardial-brain isoenzyme CK-MB concentrations and white cell counts.

RESULTS

Compared with the control group, IL-6 and IL-8-values in the parecoxib group increased to a lesser extent, peaking at 2 h after the end of CPB (IL-6 31.8 pg ml⁻¹ ± 4.7 vs. 77.0 pg ml⁻¹ ± 14.1, 95% CI -47.6, -42.8, P < 0.001; IL-8 53.6 pg ml⁻¹ ± 12.6 vs. 105.7 pg ml⁻¹ ± 10.8, 95% CI -54.8, -49.4, P < 0.001). Peak concentrations of anti-inflammatory cytokine IL-10 occurred immediately after termination of CPB and were higher in the parecoxib group (115.7 pg ml⁻¹ ± 10.5 vs. 88.4 pg ml⁻¹ ± 12.3, 95% CI 24.7, 29.9, P < 0.001). Furthermore, the increase in neutrophil counts caused by CPB during cardiac surgery was inhibited by parecoxib. The increases in serum troponin T and CK-MB concentrations were also significantly attenuated by parecoxib in the early post-operative days. Peak serum concentrations of CK-MB in both groups occurred at 24 h post-CPB (17.4 μg l⁻¹ ± 5.2 vs. 26.9 μg l⁻¹ ± 6.9, 95% CI -10.9, -8.1, P < 0.001). Peak troponin T concentrations occurred at 6 h post-bypass (2 μg l⁻¹ ± 0.62 vs. 3.5 μg l⁻¹ ± 0.78, 95% CI -1.7, -1.3, P < 0.001).

CONCLUSION

Intra-operative parecoxib attenuated the systemic inflammatory response associated with CPB during cardiac surgery and lowered the biochemical markers of myocardial injury.

Effects of a proteasome inhibitor on the NF-κB signalling pathway in experimental osteoarthritis

OBJECTIVES

To evaluate the effects of the proteasome inhibitor MG-132 on the expression of nuclear factor (NF)-κB p65, inhibitor (I)-κB, tumour necrosis factor (TNF)-α, and interleukin (IL)-1β in the cartilage and synovial tissues of rats with osteoarthritis (OA), and to investigate the role that the ubiquitin/proteasome system (UPS) plays in the OA process.

METHOD

A total of 144 adult male Sprague Dawley rats were randomly assigned to four groups: anterior cruciate ligament transaction (ACLT) + MG-132 (ACLT/M), ACLT + dimethylsulfoxide (ACLT/D), sham surgery (Sham), and naïve + MG-132 (naïve/M). Pathological morphology was undertaken. mRNA expression levels of NF-κB p65, I-κB, TNF-α, and IL-1β were determined using real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR). The activities of the 20S proteasome chymotrypsin-like and peptidylglutamyl-peptide hydrolase-like enzymes were measured using fluorospectrophotometry.

RESULTS

The Mankin scores at all time points in ACLT/M rats were significantly lower than those in ACLT/D rats (p < 0.05). Despite the NF-κB p65 in the synovial tissue at 2 weeks after surgery and IL-1β in the cartilage tissue at 12 weeks after surgery, mRNA expression levels of NF-κB p65, IL-1β, and TNF-α at other time points in ACLT/M were significantly lower than those in ACLT/D (p < 0.05). mRNA levels of I-κB in the cartilage tissue in ACLT/M were significantly higher than those in ACLT/D at 2 weeks after surgery (p < 0.05). mRNA levels of I-κB in the synovial tissue in ACLT/M were higher than those in ACLT/D at all time points, and the difference was significant at 4 weeks after surgery (p < 0.05). MG-132 decreased the activities of the 20S proteasome chymotrypsin-like and peptidylglutamyl-peptide hydrolase-like enzymes in the cartilage and synovial tissues of rats.

CONCLUSIONS

The proteasome inhibitor MG-132 delays the progress of OA by alleviating synovial inflammation and protecting the articular cartilage tissue.

A double-blind randomized controlled trial comparing the effects of subacromial injection with corticosteroid versus NSAID in patients with shoulder impingement syndrome

HYPOTHESIS

The objective of this study was to compare the efficacy of subacromial injection of triamcinolone compared to injection of ketorolac in the treatment of external shoulder impingement syndrome.

METHODS

Thirty-two patients diagnosed with external shoulder impingement syndrome were included in this double-blinded randomized controlled clinical trial. Each patient was randomized into the steroid group or nonsteroidal anti-inflammatory drugs (NSAID) group. The steroid syringe contained 40 mg triamcinolone; and the NSAID syringe contained 60 mg ketorolac. Each patient was evaluated in terms of arc of motion, visual analog scale (VAS) for evaluating pain, and the UCLA (The University of California at Los Angeles) shoulder rating scale.

RESULTS

At 1 month follow-up, both treatment arms resulted in increased range of motion and decreased pain. The steroid group decreased in active abduction while the NSAID group increased (steroid: 134°, NSAID: 151°, P = .03). The mean improvement in the UCLA shoulder rating scale at 4 weeks was 7.15 for the NSAID group and 2.13 for the steroid group (P = .03). Subgroup analysis of the UCLA scale demonstrated an increase in both forward flexion strength (P = .04) and patient satisfaction (P = .03) in the NSAID group. No significant difference could be seen in all other outcome measures.

CONCLUSION

In this study, an injection of ketorolac resulted in greater improvements in the UCLA shoulder rating scale than an injection of triamcinolone at 4 weeks follow-up. While both triamcinolone and ketorolac are effective in the treatment of isolated subacromial impingement, ketorolac appears to have equivalent if not superior efficacy; all the while decreasing patient exposure to the potential side-effects of corticosteroids.

Early intraarticular injection of hyaluronic acid attenuates osteoarthritis progression in anterior cruciate ligament-transected rats

SUBJECT

Hyaluronic acid (HA) is widely used to relieve the symptoms of osteoarthritis (OA). An association of reduction of glutamate content with the synovial fluid of OA rats was reported previously.

DESIGN

Anterior cruciate ligament transaction (ACLT) was performed on one knee in male Wistar rats, the other knee was assigned to sham control and HA or saline was injected intraarticularly into the ACLT knee from week 3 to week 7. Knee dialysate was collected for amino acid measurement at week 20. Morphology and histopathology of the femoral medial condyles and synovium were examined and evaluated using Mankin and synovitis scores.

RESULTS

HA injection provided better cartilage (3.38 ± 0.03 vs. 5.45 ± 0.0.02) and synovial condition (3 ± 0.02 vs. 6.03 ± 0.02) than saline controls. Moreover, HA injection reduced the concentration of glutamates in knee dialysates compared to saline controls (1.11 ± 0.14-folds and 2.21 ± 0.19-folds of the sham-operated knee, respectively). Cystine/glutamate antiporter system [Formula: see text] expression was significantly downregulated in the saline group, but not in the HA group (0.32 ± 0.08-folds and 0.71 ± 0.10-folds of the sham-operated knee, respectively).

CONCLUSION

Early intraarticular injection of HA attenuates the progression of cartilage destruction in the ACLT knee, and the downregulation of the cystine/glutamate antiporter system [Formula: see text] was accompanied by the progression of OA.

Suppression of pain and joint destruction by inhibition of the proteasome system in experimental osteoarthritis

Osteoarthritis is a degenerative joint disease with pain and loss of joint function as major pathological features. Recent studies show that proteasome inhibitors reduce pain in various pathological conditions. We evaluated the effects of MG132, a reversible proteasome inhibitor on pain and joint destruction in a rat model of osteoarthritis. Osteoarthritis was induced by intraarticular injection of monosodium iodoacetate into the rat knee. Knee joint stiffness was scored and nociception was evaluated by mechanical pressure applied to the respective hind paw. Knee joint destruction was assessed by radiological and histological analyses. Expression of matrix metalloproteinase-3 (MMP-3) was analyzed by quantitative reverse transcription polymerase chain reaction in the knee articular cartilage. Expression of substance P (SP) and calcitonin gene-related peptide (CGRP) was studied in the dorsal root ganglia (L4-L6) by quantitative reverse transcription polymerase chain reaction and in the knee joints by immunohistochemistry. Our results indicate that daily treatment of osteoarthritic rats with MG132 significantly increases their mobility while the swelling, pain thresholds, and pathological features of the affected joints were reduced. Furthermore, the upregulated expression of MMP-3, SP, and CGRP in the arthritic rats was normalized by MG132 administration. We conclude that the proteasome inhibitor MG132 reduces pain and joint destruction, probably by involving the peripheral nervous system, and that changes in SP and CGRP expression correlate with alterations in behavioural responses. Our findings suggest that nontoxic proteasome inhibitors may represent a novel pharmacotherapy for osteoarthritis.

Regulation of the inflammatory response by tin protoporphyrin IX in the rat anterior cruciate ligament transection model of osteoarthritis

The purpose of this study was to investigate several inflammatory mediators and cartilage degradation molecules as possible biomarkers of joint lesion in the anterior cruciate ligament transection (ACLT) model of osteoarthritis in rats. We also assessed whether the treatment with the anti-inflammatory agent tin protoporphyrin IX (SnPP) reduces the progression of disease. Our results indicate that serum levels of interleukin (IL)-6 and PGE(2) are significantly increased in ACLT rats 10 weeks after surgery, whereas the increases in IL-1β and tumor necrosis-α were not significant. In addition, our data suggest that IL-17 is the main pro-inflammatory cytokine in the ACLT joint. We have shown that serum C-telopeptide of type II collagen (CTX-II) is a biomarker better than cartilage oligomeric matrix protein, whereas hyaluronic acid showed no correlation with disease progression. Administration of SnPP (i.p. 12 mg/kg BW/day for 10 weeks) reduces the severity of structural changes and the levels of CTX-II, IL-6, and PGE(2) in serum and IL-17 and PGE(2) in ACLT knees. These effects on PGE(2) are dependent on the down-regulation of cyclooxygenase-2. Our findings indicate that systemic and local inflammatory mediators participate in the rat ACLT model and anti-inflammatory strategies may help to reduce the progression of joint lesion.

Glutamate pharmacology and metabolism in peripheral primary afferents: physiological and pathophysiological mechanisms

In addition to using glutamate as a neurotransmitter at central synapses, many primary sensory neurons release glutamate from peripheral terminals. Primary sensory neurons with cell bodies in dorsal root or trigeminal ganglia produce glutaminase, the synthetic enzyme for glutamate, and transport the enzyme in mitochondria to peripheral terminals. Vesicular glutamate transporters fill neurotransmitter vesicles with glutamate and they are shipped to peripheral terminals. Intense noxious stimuli or tissue damage causes glutamate to be released from peripheral afferent nerve terminals and augmented release occurs during acute and chronic inflammation. The site of action for glutamate can be at the autologous or nearby nerve terminals. Peripheral nerve terminals contain both ionotropic and metabotropic excitatory amino acid receptors (EAARs) and activation of these receptors can lower the activation threshold and increase the excitability of primary afferents. Antagonism of EAARs can reduce excitability of activated afferents and produce antinociception in many animal models of acute and chronic pain. Glutamate injected into human skin and muscle causes acute pain. Trauma in humans, such as arthritis, myalgia, and tendonitis, elevates glutamate levels in affected tissues. There is evidence that EAAR antagonism at peripheral sites can provide relief in some chronic pain sufferers.

The OARSI histopathology initiative - recommendations for histological assessments of osteoarthritis in the rat

OBJECTIVE

During the development of disease-modifying osteoarthritis (OA) drugs, rat models of OA are frequently used for a first assessment of in vivo efficacy. The most efficacious compound in the rat model may then be tested in a larger animal model before entering human trials. The aim of this study was to describe a histologic scoring system for use in different models of OA in rats that allows standardization and comparison of results obtained by different investigators.

METHODS

The experience of the authors with current scoring systems and the range of lesions observed in rat and human OA studies were considered in recommending this common paradigm for rat histologic scoring. Considerations were made for reproducibility and ease of use for new scorers. Additional scoring paradigms may be employed to further identify specific effects of some disease-modifying drugs.

RESULTS

Although the described scoring system is more complex than the modified Mankin scores, which are recommended for some other species, the reliability study showed that it is easily understood and can be reproducibly used, even by inexperienced scorers.

CONCLUSIONS

The scoring paradigm described here has been found to be sufficiently sensitive to discriminate between treatments and to have high reproducibility. Therefore we recommend its use for evaluation of different rat OA models as well as assessment of disease-modifying effects of treatments in these models.

Glucosamine sulfate reduces experimental osteoarthritis and nociception in rats: association with changes of mitogen-activated protein kinase in chondrocytes

OBJECTIVE

To study the effects of oral glucosamine sulfate on the development of osteoarthritis (OA) and to examine concomitant changes in the nociceptive behavior of rats.

METHODS

OA was induced in Wistar rats by anterior cruciate ligament transection (ACLT) of the right knee; the left knee was untreated. The OA+glucosamine group received oral glucosamine sulfate (250 mg/kg/day) in a 2-g wafer once a day for 10 consecutive weeks starting at week 5 after ACLT. The OA group was treated as above with 2-g wafers (placebo). The control group of naïve rats received 2-g wafers only. The glucosamine alone group comprised naïve rats receiving glucosamine sulfate only. Nociceptive behavior (mechanical allodynia and weight-bearing distribution of hind paws) during OA development was analyzed pre- and 3, 6, 9, 12, 15, and 18 weeks post-ACLT. Macroscopic and histologic studies were then performed on the cartilage and synovia. Immunohistochemical analysis was performed to examine the effect of glucosamine on expression of mitogen-activated protein kinases (MAPKs) in the articular cartilage chondrocytes.

RESULTS

OA rats receiving glucosamine showed a significantly lower degree of cartilage degeneration than the rats receiving placebo. Glucosamine treatment also suppressed synovitis. Mechanical allodynia and weight-bearing distribution studies showed significant improvement in the OA+glucosamine group as compared to the OA group. Moreover, glucosamine attenuated p38 and c-Jun N-terminal kinase (JNK) but increased extracellular signal-regulated kinase 1/2 (ERK) expression in OA-affected cartilage.

CONCLUSION

Our results indicate that treatment with oral glucosamine sulfate in a rat OA model (1) attenuates the development of OA, (2) concomitantly reduces nociception, and (3) modulates chondrocyte metabolism, possibly through inhibition of cell p38 and JNK and increase of ERK expression.

Intra-articular magnesium sulfate (MgSO4) reduces experimental osteoarthritis and nociception: association with attenuation of N-methyl-D-aspartate (NMDA) receptor subunit 1 phosphorylation and apoptosis in rat chondrocytes

OBJECTIVE

To study the effects of intra-articular injection of magnesium sulfate (MgSO(4)) on the development of osteoarthritis (OA) and to examine concomitant changes in the nociceptive behavior of rats.

METHODS

OA was induced in Wistar rats with intra-articular injection of collagenase (500 U) in the right knee; the left knee was left untreated. In the OA+MgSO(4) group (n=7), the treated knee was injected with 500-microg (0.1-ml) MgSO(4) twice a week for 5 consecutive weeks starting at 1 week after collagenase injection; in the OA group (n=7), the same knee was injected with the same amount of physiological normal saline. In the MgSO(4) group (n=6), naïve rats received only MgSO(4) injections; in the control group (n=6), naïve rats received only physiological normal saline injections. Nociceptive behavior (mechanical allodynia and thermal hyperalgesia) on OA development was measured before and at 1, 2, 4, 6, and 8 weeks after collagenase injection, following which the animals were sacrificed. Gross morphology and histopathology were examined in the femoral condyles, tibial plateau, and synovia. Immunohistochemical analysis was performed to examine the effect of MgSO(4) on N-methyl-D-aspartate (NMDA) receptor subunit 1 phosphorylation (p-NR1) and apoptosis in the articular cartilage chondrocytes.

RESULTS

OA rats receiving intra-articular MgSO(4) injections showed a significantly lower degree of cartilage degeneration than the rats receiving saline injections. MgSO(4) treatment also suppressed synovitis. Mechanical allodynia and thermal hyperalgesia showed significant improvement in the OA+MgSO(4) group as compared to the OA group. Moreover, MgSO(4) attenuated p-NR1 and chondrocyte apoptosis in OA-affected cartilage.

CONCLUSIONS

Our results indicate that local intra-articular administration of MgSO(4) following collagenase injection in an experimental rat OA model (1) modulates chondrocyte metabolism through inhibition of cell NMDA receptor phosphorylation and apoptosis, (2) attenuates the development of OA, and (3) concomitantly reduces nociception.

Glutamate signaling in chondrocytes and the potential involvement of NMDA receptors in cell proliferation and inflammatory gene expression

OBJECTIVE

Increased levels of glutamate, the main excitatory neurotransmitter, are found in the synovial fluid of osteoarthritis (OA) patients. Our aim was to study glutamate signaling in chondrocytes, focusing on the composition, pharmacology, and functional role of N-methyl-d-aspartate (NMDA) glutamate receptors.

METHODS

We used the human chondrocyte cell line SW1353 and, in parallel, primary rat articular chondrocytes. Glutamate release and uptake were measured by fluorimetric and radiometric methods, respectively. Gene expression was analyzed by quantitative polymerase chain reaction. NMDA receptor pharmacology was studied in binding experiments with [3H]MK-801, a specific NMDA receptor antagonist. RNA interference was used to knock-down the expression of NR1, a subunit of NMDA receptors.

RESULTS

Glutamate release, sodium- and calcium-dependent glutamate uptake, and the expression of a glutamate transporter were observed in chondrocytes. NR2D was the most abundant NMDA receptor subunit in these cells. Consistent with this observation, the binding affinity of [3H]MK-801 was much lower in chondrocytes than in rat brain membranes (mean K(d) values of 700 and 2.6 nM, respectively). NR1 knock-down, as well as NMDA receptor blockade with MK-801, reduced chondrocyte proliferation. Interleukin (IL)-1beta significantly altered glutamate release and uptake (about 90% increase and 50% decrease, respectively, in SW1353 cells). Moreover, IL-1beta induced the gene expression of cytokines and enzymes involved in cartilage degradation, and MK-801 significantly inhibited this response.

CONCLUSIONS

Our findings suggest that chondrocytes express a self-sufficient machinery for glutamate signaling, including a peripheral NMDA receptor with unique properties. This receptor may have a role in the inflammatory process associated with cartilage degradation, thus emerging as a potential pharmacological target in OA.

Increase in excitatory amino acid concentration and transporters expression in osteoarthritic knees of anterior cruciate ligament transected rabbits

OBJECTIVE

The present study aimed to determine the role of excitatory amino acids (EAAs) and EAA transporters (EAATs) in an osteoarthritis (OA) model of rabbit knees.

METHODS

OA was induced in New Zealand white male rabbits by anterior cruciate ligament transection (ACLT) in one knee of one hind limb; the other knee left unoperated. Rabbits that received ACLT of knee were assigned to the ACLT group (n=6), while a sham-operated group (n=6) underwent arthrotomy with no ACLT. Six naïve rabbits that received no surgery were used as normal control. The width of the knee joint was measured to determine the severity of joint inflammation. Before operation and at 10, 20, and 30 weeks after operation, knee joint dialysates were collected by microdialysis and assayed for EAAs by high-performance liquid chromatography. Gross morphology and histopathology and EAATs glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) expression in the articular cartilage of the knees were evaluated by immunohistochemistry and western blot analysis.

RESULTS

In the ACLT knees, a significant increase in the joint width was observed (5.3+/-0.9 mm, P<0.05) at 30 weeks after operation, while the sham-operated and naïve knees showed no difference as compared with the basal values. The concentrations (microM) of aspartate and glutamate in knee dialysates at 30 weeks after ACLT in naïve, sham, and ACLT were 0.36+/-0.07 and 4.5+/-1.10; 0.38+/-0.09 and 4.61+/-1.11; 0.67+/-0.18 and 9.71+/-2.89, respectively. Levels of glutamate and aspartate in the dialysates obtained from the ACLT knees increased by 213.3+/-29.6% and 187.5+/-33.8% (P<0.05) when compared to those in the sham-operated knees. Both naïve and ACLT chondrocytes were positively stained by antibodies against GLAST and GLT-1. GLAST and GLT-1 protein expressions were significantly increased in the ACLT knees (P<0.05).

CONCLUSION

Our findings indicate an involvement of EAAs and EAATs in the pathogenesis of OA in ACLT rabbits.