The preventive effects of two nutraceuticals on experimentally induced acute synovitis.

BACKGROUND: Nutraceuticals are often used in the management of equine osteoarthritis, but scientific evidence of their efficacy is lacking. OBJECTIVES: To study the preventive effects of two new nutraceuticals after the experimental induction of synovitis in comparison with positive and negative control treatments. STUDY DESIGN: Blinded, controlled, randomised experiment. METHODS: Twenty-four healthy Standardbred horses were randomly allocated to supplement AT (multi-ingredient, 28 days), supplement HP (collagen hydrolysate, 60 days), meloxicam (4 days) or placebo (60 days). Synovitis was induced in the right intercarpal joint by intra-articular injection of 0.5 ng lipopolysaccharide (LPS) of Escherichia coli while treatments were continued. Blood and synovial fluid were sampled before treatment, immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Synovial fluid samples were analysed for total nucleated cell count (TNCC), total protein (TP) and selected biomarkers (prostaglandin E2 [PGE2 ], interleukin-6 [IL-6], glycosaminoglycans [GAGs], type II collagen synthesis [CPII], matrix metalloproteinase [MMP]). Lameness was scored by visual examination and pressure plate analysis immediately prior to LPS injection, and at 8, 24 and 48 h post-injection. Clinical examinations were performed before treatment, immediately prior to LPS injection, at 2, 4 and 6 h post-injection, and then twice per day during the test period. RESULTS: Before treatment and intra-articular challenge, there were no statistically significant differences among the treatment groups for any of the parameters. After intra-articular challenge, the placebo group showed significantly higher synovial fluid TP, TNCC and PGE2 compared with the meloxicam group, although the model did not induce a relevant amount of lameness. Both nutraceuticals resulted in significantly lower synovial fluid TP, TNCC and PGE2 compared with placebo. No statistical differences in IL-6, GAGs, CPII or MMPs were observed among treatment groups. No adverse effects were observed. MAIN LIMITATIONS: Despite evidence of synovitis, lameness was too mild to detect. CONCLUSIONS: The preventive administration of these nutraceuticals showed anti-inflammatory effects in this validated synovitis model. Therefore, further studies of their clinical applicability are warranted.

Influence of an n-3 long-chain polyunsaturated fatty acid-enriched diet on experimentally induced synovitis in horses.

Dietary n-3 long-chain polyunsaturated fatty acid (LCPUFA) supplementation has previously been shown to modify joint-related inflammation in several species, although information in the horse is lacking. We investigated whether dietary supplementation with n-3 LCPUFA would modify experimentally induced synovitis in horses. Twelve, skeletally mature, non-pregnant mares were randomly assigned to either a control diet (CONT) or an n-3 long-chain fatty acid-enriched treatment diet (N3FA) containing 40 g/day of n-3 LCPUFA for 91 days. Blood samples taken on days 0, 30, 60 and 90, and synovial fluid collected on days 0 and 90 were processed for lipid composition. On day 91, joint inflammation was stimulated using an intra-articular (IA) injection of 100 ng of recombinant equine IL-1beta (reIL-1ß). Synovial fluid samples taken at post-injection hours (PIH) 0, 4, 8 and 24 were analysed for prostaglandin E2 (PGE2 ), matrix metalloproteinase (MMP) activity and routine cytology. Synovium and articular cartilage samples collected at PIH 8 were analysed for gene expression of MMP 1 and MMP 13, interleukin-1beta (IL-1ß), cyclooxygenase 2 (COX-2), tumour necrosis factor-alpha and the aggrecanases, a disintegrin and metalloprotease with thrombospondin motifs (ADAMTS)-4 and ADAMTS-5. A 90-day feeding period of n-3 LCPUFA increased serum phospholipid and synovial fluid lipid compositions of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) compared to CONT horses. The reIL-1ß injection caused an inflammatory response; however, there was no effect of dietary treatment on synovial fluid PGE2 content and MMP activity. Synovial tissue collected from N3FA horses exhibited lower expression of ADAMTS-4 compared to CONT horses. Despite the presence of EPA and DHA in the synovial fluid of N3FA horses, dietary n-3 LCPUFA supplementation did not modify synovial fluid biomarkers compared to CONT horses; however, the lower ADAMTS-4 mRNA expression in N3FA synovium warrants further investigation of n-3 LCPUFA as a joint therapy.

Bacteria and Toll-like receptor and cytokine mRNA expression profiles associated with canine arthritis.

The major forms of inflammatory canine arthritis are immune-mediated arthritis (IMA) and septic arthritis (SA), although some cases of cruciate disease (CD) are associated with significant levels of synovitis. In this study, the bacteria associated with canine arthritis were identified and mRNA expression levels of Toll-like receptors (TLRs) and pro-inflammatory cytokines determined. Of the 40 synovial fluid samples analysed, bacteria were isolated from 12 samples by culture (2 CD, 10 SA) and detected in 4 samples (3 CD, 1 SA) using culture-independent methods. Statistically significant increases in TLR2, tumour necrosis factor-α (TNF-α), interleukin-6 (IL-6) and IL-12 mRNA expression were seen in all disease groups compared to normal controls. All disease groups had decreased mRNA expression of other TLRs compared to normal controls, but this did not reach statistical significance. Synovial fluid cell counts revealed that the highest number and proportion of mononuclear cells and neutrophils were found in the IMA and SA samples, respectively. Age had an effect on the TLR and cytokine mRNA expression profiles: TNF-α (p=0.043) and IL-12 (p=0.025) mRNA expression was increased and TLR4 mRNA expression was reduced (p=0.033) in dogs up to 4 years of age compared to older animals. In the 10 SA samples from which bacteria were isolated, statistically significant increases in TLR2, TLR7, TNF-α and IL-6 mRNA expression were observed. It is concluded that canine arthritis is associated with increased mRNA levels of pro-inflammatory cytokines, which could in some cases be mediated by bacteria through activation of TLR2.

Effect of anesthetizing individual compartments of the stifle joint in horses with experimentally induced stifle joint lameness.

OBJECTIVE: To evaluate the effects of sequential anesthesia of the individual compartments of the equine stifle joint on lameness induced by intra-articular deposition of interleukin (IL)-1ß. ANIMALS: 6 horses. PROCEDURES: For each horse, baseline hind limb lameness was first evaluated. A randomly selected compartment of 1 stifle joint was then injected with IL-1ß to induce synovitis and lameness; subsequently, the same compartment was anesthetized with 2% mepivacaine hydrochloride, and lameness was reevaluated. Two weeks later, baseline lameness was evaluated, and lameness was similarly induced; thereafter, the 2 synovial compartments of the stifle joint not injected with IL-1ß were anesthetized sequentially in random order (ie, first and second blocks); lameness was evaluated after each block. Finally, the IL-1ß-treated compartment was anesthetized (third block); lameness was again evaluated. This second experiment was repeated for the contralateral stifle joint 2 weeks later. Throughout the study, lameness was quantified objectively by assessing vertical pelvic movement asymmetry with a wireless, inertial sensor-based system. RESULTS: Intra-articular deposition of IL-1ß induced lameness in all injected limbs. In the first experiment, anesthesia of the compartment injected with IL-1ß resulted in a significant decrease in lameness, with vertical pelvic movement asymmetry approaching baseline. In the second experiment, lameness improved significantly after the second and third blocks and was almost completely abolished after all 3 synovial compartments were anesthetized. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, lameness caused by a lesion in 1 compartment of a stifle joint can be improved more by instillation of local anesthetic solution into that compartment than by anesthesia of the other compartments.

Efficacy of ABT-116, an antagonist of transient receptor potential vanilloid type 1, in providing analgesia for dogs with chemically induced synovitis.

OBJECTIVE: To investigate the ability of ABT-116 (a proprietary antagonist of transient receptor potential vanilloid type 1) administered at 2 doses to attenuate lameness in dogs with experimentally induced urate synovitis. ANIMALS: 8 purpose-bred mixed-breed dogs. PROCEDURES: In a 4-way crossover study, dogs orally received each of low-dose ABT-116 treatment (LDA; 10 mg/kg), high-dose ABT-116 treatment (HDA; 30 mg/kg), firocoxib (5 mg/kg), and no treatment (nontreatment) once a day for 2 days, in a randomly assigned order. Synovitis was induced on the second day of each treatment period by intra-articular injection of either stifle joint with sodium urate, alternating between joints for each treatment period, beginning with the left stifle joint. Ground reaction forces, clinical lameness scores, and rectal temperature were assessed before the injection (baseline) and at various points afterward. RESULTS: Lameness scores at the 2-, 6-, and 12-hour assessment points were higher than baseline scores for HDA and nontreatment, whereas scores at the 2- and 6-hour points were higher than baseline scores for LDA. For firocoxib, there was no difference from baseline scores in lameness scores at any point. Compared with baseline values, peak vertical force and vertical impulse were lower at 2 and 6 hours for HDA and nontreatment and at 2 hours for LDA. No changes in these values were evident for firocoxib. The HDA or LDA resulted in higher rectal temperatures than did treatment with firocoxib or nothing, but those temperatures did not differ among treatments. CONCLUSIONS AND CLINICAL RELEVANCE: HDA had no apparent effect on sodium urate-induced lameness; LDA did attenuate the lameness but not as completely as firocoxib treatment. High rectal temperature is an adverse effect of oral ABT-116 administration that may be of clinical concern.

Are bacterial load and synovitis related in dogs with inflammatory stifle arthritis?

It has been proposed that small quantities of microbial material within synovial joints may act as a trigger for development of synovitis. We have previously identified an association between intra-articular bacteria and development of inflammatory stifle arthritis and cranial cruciate ligament rupture (CCLR) in dogs, and now wished to quantify bacterial load and markers of synovitis in dogs with and without stifle arthritis and CCLR. Joint tissues were collected from dogs with CCLR (n=51) and healthy dogs with normal stifles (n=9). Arthritis was assessed radiographically in CCLR dogs. Bacterial load was assessed using qPCR and broad-ranging 16S rRNA primers. qRT-PCR was used to estimate expression of the T lymphocyte antigen receptor (TCR Vß), CD3ɛ, tartrate-resistant acid phosphatase (TRAP), IL-4, IL-17, and TNF-α genes. Severity of synovitis was assessed histologically. Bacterial load was increased in arthritic stifles, when compared with healthy stifles. Histologic synovitis in arthritic stifles was mononuclear and was significantly correlated with bacterial load (1 of 2 primer sets) (S(R)=0.49, p<0.001). In arthritic stifles, expression of TRAP in synovium was increased relative to healthy stifles. Expression of pro-inflammatory genes was not correlated with bacterial load, histologic inflammation, or radiographic arthritis. Translocation of bacterial material to the canine stifle is related to the presence of joint inflammation. The lack of a strong positive correlation suggests that bacterial load is unlikely to be a primary pro-inflammatory factor. However, dysregulation of immune responses within synovial tissues may be dependent upon an environmental microbial trigger.

Effect of deracoxib, a new COX-2 inhibitor, on the prevention of lameness induced by chemical synovitis in dogs.

Twenty-four healthy, mixed-breed hound-type dogs were evenly and randomly assigned to a placebo control group, one of four dosages of deracoxib (0.3, 1, 3, or 10 mg/kg), or carprofen (2.2 mg/kg). Oral dosing of placebo, carprofen, or deracoxib was done 30 minutes before intraarticular injection of urate crystal suspension for induction of synovitis. Ground reaction forces, subjective clinical lameness scores, pain, joint effusion, and quantitative pain threshold responses were measured in a blinded fashion before induction of synovitis and 2, 4, 6, 8, 12, and 24 hours after injection. The medium and high dosages of deracoxib were effective in preventing lameness and pain associated with synovitis. Carprofen was also somewhat effective in attenuating the severity of urate-induced synovitis but to a lesser degree than the medium dose of deracoxib. Preemptive deracoxib treatment at dosages as low as 1 mg/kg reduced lameness and pain of synovitis associated with intraarticular administration of urate crystals.

Treatment of traumatically induced synovial sepsis in horses with gentamicin-impregnated collagen sponges.

Eight horses with synovial sepsis induced by trauma were treated by arthroscopic/tenoscopic debridement and lavage followed by the implantation of a gentamicin-impregnated collagen sponge. Seven of them responded favourably and were sound six months after treatment. The other underwent a further surgical procedure and recovered. Gentamicin-impregnated collagen sponges appear to be a safe and useful adjunct in the treatment of septic joints and tendon sheaths, and have the advantage of being bioabsorbable.

Effects of the NSAIDs meloxicam and indomethacin on cartilage proteoglycan synthesis and joint responses to calcium pyrophosphate crystals in dogs.

NSAIDs are a major cause for concern for their propensity to cause joint deterioration in canine, as in human, patients receiving these drugs for treatment of pain in osteoarthritis and other acute and chronic painful conditions. To determine the potential effects of the new NSAID meloxicam on cartilage integrity, the effects of this drug on proteoglycan biosynthesis in vitro and ex vivo were compared with those of indomethacin, a known inhibitor of sulphated proteoglycans that accelerates joint injury in human osteoarthritis. In vitro cartilage proteoglycan synthesis from a radiosulphate precursor was unaffected by 0.5-10.0 micromol/L meloxicam but was significantly inhibited by 50 micromol/L indomethacin after 6 or 24 h incubation of femoral or tibial cartilage explants in organ culture. This is in accord with previous observations in human or porcine articular cartilage under the same culture conditions. Studies were performed in vivo to establish the effects of the NSAIDs on joint integrity. This involved determining cartilage proteoglycan synthesis ex vivo, leukocyte, fluid and protein accumulation, as well as pain relief. Thus, meloxicam (0.2 mg/kg i.v. x 3 doses) or indomethacin (0.5 mg/kg i.v. x 3 doses) was given for 26 h and the effects were compared with a control (1.0 ml saline i.v. x 3 doses) in dogs in which acute inflammation had been induced by intra-articular (i.a.) injection of calcium pyrophosphate dihydrate (CPPD) crystals into the right stifle joint, an equivalent volume of saline being injected into the left stifle joint as a control. No effects were observed of the treatment with the NSAIDs on ex vivo sulphated proteoglycan synthesis. The lack of the expected inhibitory effects of indomethacin may be related to the relatively low plasma concentrations of this drug obtained during the 26 h period of treatment. The pain response, which was elicited up to 6 h following i.a. injection of CPPD crystals, was totally prevented by the treatment with meloxicam and to a lesser extent with indomethacin. There were no effects from the drug treatment on synovial inflammatory reactions (fluid and cell accumulation), although the protein concentration of the exudate was reduced by meloxicam. This indicates that, at the doses given, it was possible to discriminate the analgesic action from the anti-inflammatory action of the two NSAIDs, this being achieved at relatively low plasma concentrations of these drugs. In conclusion, while relatively high therapeutic concentrations of indomethacin inhibit cartilage proteoglycan synthesis, this is not an effect seen even at high concentrations of meloxicam. Furthermore, the lack of effects on proteoglycan synthesis was evident when these two drugs were given in vivo to dogs. However, the signs of pain, but not the inflammation in the joint, were relieved by low plasma concentrations of the drugs. Meloxicam may thus be safely employed for acute analgesia without the potential risks of joint cartilage damage that occurs with indomethacin given at antiinflammatory doses for long periods of time.

Kinetic gait analysis assessment of meloxicam efficacy in a sodium urate-induced synovitis model in dogs.

OBJECTIVE: To examine the ability of meloxicam, a cyclooxygenase inhibitor, to mediate the effects of sodium urate-induced acute stifle synovitis in dogs. ANIMALS: 12 clinically normal adult hound-type dogs. PROCEDURE: A blinded, randomized, controlled single crossover design study was performed to determine the efficacy of meloxicam, using 2 dosage groups. In 2 experimental phases, dogs, according to group, received meloxicam (0.1 or 0.5 mg/kg of body weight) or matched volume of meloxicam vehicle, with a washout period of 21 to 28 days between phases. Blood samples for hematologic and biochemical analysis, as well as synovial fluid or cytologic analysis, were collected immediately before and approximately 24 hours after articular challenge of dogs under propofol anesthesia. Ground reaction forces (GRF) and subjective clinical scores were determined before and at 4, 8, 12, and 24 hours after articular challenge. Vertical force data included peak force, impulse, limb loading, and unloading rates. Craniocaudal data were divided into braking and propulsion phases and consisted of peak force and associated impulses. RESULTS: Except for propulsion impulse at 24 hours, all GRF variables were significantly greater at all post-synovitis induction times in the group receiving the high meloxicam dose. Significant differences in all GRF variables were seen at various times between the low-dose meloxicam group and the corresponding control group, and between the low- and high-dose meloxicam groups. Similar significance was seen in the subjective clinical evaluations. Strong correlations existed between the subjective and objective data. CONCLUSIONS: Meloxicam was effective in attenuating the effects of sodium urate-induced acute synovitis in dogs. Kinetic gait data provided an objective measurement of lameness in an experimentally induced arthritis model and quantified lameness improvements in response to medication with a nonsteroidal anti-inflammatory drug.

Concentration and molecular weight distribution of hyaluronate in synovial fluid from clinically normal horses and horses with diseased joints.

High molecular weight (MW) hyaluronate (HA) is an integral part of synovial fluid (SF), regulating many important physiologic and pathophysiologic mechanisms. Many of its effects depend on, or are reflected in, the concentration and MW of HA. High-performance liquid chromatography was used to assess simultaneously the concentration and MW of HA in SF obtained from horses with various arthritides: acute traumatic arthritis; chronic traumatic arthritis, including degenerative joint disease (DJD); and infectious arthritis. The size-exclusion column was calibrated, using appropriate HA concentration and MW standards, before the high-performance liquid chromatographic assays of the SF samples. Calibration of the column disclosed that the maximal limit for MW estimation of HA was around 3 million. In control joints, MW of HA ranged from 2 to 3 x 10(6) (mean 2.5 x 10(6)) and did not differ significantly from MW of HA in SF from horses with acute or chronic traumatic arthritis (mean 2 x 10(6); range 1.5 to 3 x 10(6)). Interestingly, a small amount of HA of moderately high MW (approx 1 to 1.5 x 10(6)) was detected in chromatograms of SF from infected joints. This degree of polymerization of SF HA was significantly (P < 0.01) lower, compared with that for control joints. There was no difference in mean (+/- SD) concentration of HA between control joints and joints with acute or chronic traumatic arthritis (0.33 +/- 0.12 g/L vs 0.18 +/- 0.03 g/L or 0.23 +/- 0.12 g/L), indicating that SF HA concentration probably should not be used as a diagnostic marker for the condition.(ABSTRACT TRUNCATED AT 250 WORDS)