Determination of MMP-2 and -9 activities in synovial fluid of horses with osteoarthritic and arthritic joint diseases using gelatin zymography and immunocapture activity assays

Effects of High-Speed Training on Messenger RNA Expression in Two-Year-Old Thoroughbred Racehorses

Accumulating high-speed exercise has been identified as a significant risk factor for catastrophic injuries in racing Thoroughbreds. Injuries, regardless of severity, are a main cause of withdrawal from the racing industry, raising animal welfare concerns and resulting in significant economic losses. While most of the current literature focuses on injuries incurred during racing rather than training, the present study aims to help fill this gap. As such, peripheral blood was collected weekly, prior to exercise or administration of medication, from eighteen, two-year-old Thoroughbreds throughout their first season of race training. Messenger RNA (mRNA) was isolated and used to analyze the expression of 34 genes via RT-qPCR. Statistical analysis of the noninjured horses (n = 6) showed that 13 genes were significantly correlated with increasing average weekly high-speed furlong performance. Additionally, there was a negative correlation for CXCL1, IGFBP3, and MPO with both cumulative high-speed furlongs and week of training for all horses. Comparison of both groups showed opposing correlations between the anti-inflammatory index (IL1RN, IL-10, and PTGS1) and average weekly high-speed furlong performance. Furthermore, evaluation of training effects on mRNA expression during the weeks surrounding injury, showed differences between groups in IL-13 and MMP9 at -3 and -2 weeks prior to injury. While some previously reported relationships between exercise adaptation and mRNA expression were not noted in this study, this may have been due to the small sample size. Several novel correlations, however, were identified and warrant further investigation as markers of exercise adaptation or potential risk for injury.

Detection of synovial sepsis in horses using enzymes as biomarker

Background

Synovial sepsis is a commonly occurring, potentially career‐ending or even life‐threatening orthopaedic emergency. Diagnosis of synovial sepsis is currently primarily based on synovial fluid analysis, which often leaves diagnostic ambiguity due to overlap of clinicopathological parameters between septic and aseptic inflammatory synovitis.

Objectives

To evaluate the reliability of lysozyme (LYS), myeloperoxidase (MPO) and elastase (ELT) as biomarkers for synovial sepsis in horses using a photometric assay to measure increased enzyme activity.

Study design

Prospective, single‐blinded, analytical, clinical study.

Methods

Equine synovial samples were assigned to one of three groups: (1) healthy controls (n = 10), (2) aseptic (n = 27) and (3) septic synovitis (n = 30). The enzyme activity assays (LYS, MPO and ELT) were compared with standard synovial fluid parameters and broad‐range bacterial 16S rDNA PCR.

Results

LYS and MPO activities were significantly different between septic synovial samples, and both aseptic and control samples (P < .001, LYS: confidence interval [CI]: 2.25‐3.41, resp., 2.21‐3.8, MPO: CI 0.752‐1.6, resp., 0.639‐1.81). LYS achieved a 100% sensitivity and 100% specificity in differentiating between septic and aseptic (cut‐off value 751.4) or control (cut‐off: 484.6) samples (P < .001). MPO reached 93.33% sensitivity, 100% specificity for distinguishing septic from control (cut‐off value: 0.1254) synovial samples and 93.33% sensitivity, 81.48% specificity for discriminating between septic and aseptic (cut‐off value: 0.1305) synovial samples (P < .001). ELT activity could not be measured in any synovial sample. Both the LYS and the MPO measurements showed a highly significant correlation with PCR (LYS r = .79, MPO r = .69), synovial leukocyte count (LYS r = .752, MPO r = .571), % neutrophils (LYS r = .751, MPO r = 0.663) and each other (r = .744, all P < .001).

Main limitations

Variation in horses’ signalment, affected synovial structures and synovial fluid freezing times may have affected the discriminative power of this study.

Conclusions

Increased MPO and LYS activities allow reliable, rapid diagnosis of synovial sepsis with high sensitivity and specificity.

MMP-9 Concentration in Peritoneal Fluid Is a Valuable Biomarker Associated with Endotoxemia in Equine Colic

The purpose of the study was to compare the results of sepsis scoring (clinical examination and clinical pathology) to the concentrations of matrix-metalloproteinases (MMPs) -2, -8, and -9; tissue-inhibitor of metalloproteinases (TIMPs) -1 and -2; and inflammatory chemokines interleukin (IL) 1β and tumor-necrosis-factor-alpha (TNF-α) in plasma and peritoneal fluid of equine colic patients. A modified sepsis scoring including general condition, heart and respiratory rate, rectal temperature, mucous membranes, white blood cell count (WBC), and ionized calcium was applied in 47 horses presented with clinical signs of colic. Using this scoring system, horses were classified as negative (n = 32, ≤6/19 points), questionable (n = 9, 7-9/19 points), or positive (n = 6, ≥10/19 points) for sepsis. MMPs, TIMPs, IL-1β, and TNF-α concentrations were evaluated in plasma and peritoneal fluid using species-specific sandwich ELISA kits. In a linear discriminant analysis, all parameters of sepsis scoring apart from calcium separated well between sepsis severity groups (P < 0.05). MMP-9 was the only biomarker of high diagnostic value, while all others remained insignificant. A significant influence of overall sepsis scoring on MMP-9 was found for peritoneal fluid (P = 0.005) with a regression coefficient of 0.092, while no association was found for plasma (P = 0.085). Using a MMP-9 concentration of >113 ng/ml in the peritoneal fluid was found to be the ideal cutoff to identify positive sepsis scoring (≥10/19 points; sensitivity of 83.3% and specificity of 82.9%). In conclusion, MMP-9 was found to be a biomarker of high diagnostic value for sepsis and endotoxemia in equine colic. The evaluation of peritoneal fluid seems preferable in comparison to plasma. As abdominocentesis is commonly performed in the diagnostic work-up of equine colic, a pen-side assay would be useful and easy-to-perform diagnostic support in the decision for therapeutic intervention.

Pectolinarigenin inhibits cell viability, migration and invasion and induces apoptosis via a ROS-mitochondrial apoptotic pathway in melanoma cells

Pectolinarigenin a plant secondary metabolite that has various biological effects, including the inhibition of melanogenesis and tumor growth. Melanoma has a high degree of malignancy, with rapid metastasis and severe drug resistance, explaining the need for new candidate drugs that inhibit tumor growth and metastasis. However, the pharmacological action and mechanism of pectolinarigenin on the growth and metastasis of melanoma remain elusive. Thus, the present study aimed to investigate the role of pectolinarigenin in melanoma cell proliferation, apoptosis, migration and invasion. Apoptotic and metastasis-associated proteins were analyzed using western blotting. The results demonstrated that pectolinarigenin treatment resulted in growth inhibition and apoptosis induction in melanoma cells, arising from the loss of mitochondrial transmembrane potential, reactive oxygen species and the altered expression of apoptosis-associated proteins. In addition, wound-healing and Transwell assays demonstrated the potential of pectolinarigenin to impair the migration and invasion of melanoma cells in accordance with the changes in the expression of the associated proteins. Therefore, the results of the present study suggested that pectolinarigenin may serve a pivotal role in promoting melanoma cell apoptosis and reducing metastasis, and may thus be a promising potential candidate for an anti-melanoma treatment strategy.

COL2A1 and Caspase-3 as Promising Biomarkers for Osteoarthritis Prognosis in an Equus asinus Model

Osteoarthritis (OA) is one of the most degenerative joint diseases in both human and veterinary medicine. The objective of the present study was the early diagnosis of OA in donkeys using a reliable grading of the disease based on clinical, chemical, and molecular alterations. OA was induced by intra-articular injection of 25 mg monoiodoacetate (MIA) as a single dose into the left radiocarpal joint of nine donkeys. Animals were clinically evaluated through the assessment of lameness score, radiographic, and ultrasonographic findings for seven months. Synovial fluid and cartilage samples were collected from both normal and diseased joints for the assessment of matrix metalloproteinases (MMPs) activity, COL2A1 protein expression level, and histopathological and immunohistochemical analysis of Caspase-3. Animals showed the highest lameness score post-induction after one week then decreased gradually with the progression of radiographical and ultrasonographic changes. MMP activity and COL2A1 and Caspase-3 expression increased, accompanied by articular cartilage degeneration and loss of proteoglycan. OA was successfully graded in Egyptian donkeys, with the promising use of COL2A1and Caspase-3 for prognosis. However, MMPs failed to discriminate between early and late grades of OA.

Cartilage Metabolism is Modulated by Synovial Fluid Through Metalloproteinase Activity

Synovial fluid (SF) contains various cytokines that regulate chondrocyte metabolism and is dynamically associated with joint disease. The objective of this study was to investigate the effects of diluted normal SF on catabolic metabolism of articular cartilage under inflammatory conditions. For this purpose, SF was isolated from healthy bovine joints, diluted, and added to cartilage explant cultures stimulated with interleukin-1 (IL-1) for 12 days. The kinetic release of sulfated glycosaminoglycan (sGAG) and collagen, as well as nitric oxide and gelatinase matrix metalloproteinases were analyzed in the supernatant. Chondrocyte survival and matrix integrity in the explants were evaluated with Live/Dead and histological staining. Diluted synovial fluid treatment suppressed sGAG and collagen release, downregulated the production of nitric oxide and matrix metalloproteinases, reduced IL-1-induced chondrocyte death, and rescued matrix depletion. Our results demonstrate that normal SF can counteract inflammation-driven cartilage catabolism. This study reports on the protective function of healthy SF and the therapeutic potential of recapitulation of SF for cartilage repair.

Licochalcone D induces apoptosis and inhibits migration and invasion in human melanoma A375 cells

The aim of the present study was to determine the effects of Licochalcone D (LD) on the apoptosis and migration and invasion in human melanoma A375 cells. Cell proliferation was determined by sulforhodamine B assay. Apoptosis was assessed by Hoechst 33258 and Annexin V‑FITC/PI staining and JC‑1 assay. Total intracellular reactive oxygen species (ROS) was examined by DCFH‑DA. Wound healing and Transwell assays were used to detect migration and invasion of the cells. The activities of matrix metalloproteinase (MMP‑2 and MMP‑9) were assessed via gelatin zymography. Tumor growth in vivo was evaluated in C57BL/6 mice. RT‑PCR, qPCR, ELISA and western blot analysis were utilized to measure the mRNA and protein levels. Our results showed that LD inhibited the proliferation of A375 and SK‑MEL‑5 cells in a concentration‑dependent manner. After treatment with LD, A375 cells displayed obvious apoptotic characteristics, and the number of apoptotic cells was significantly increased. Pro‑apoptotic protein Bax, caspase‑9 and caspase‑3 were upregulated, while anti‑apoptotic protein Bcl‑2 was downregulated in the LD‑treated cells. Meanwhile, LD induced the loss of mitochondrial membrane potential (ΔΨm) and increased the level of ROS. ROS production was inhibited by the co‑treatment of LD and free radical scavenger N‑acetyl‑cysteine (NAC). Furthermore, LD also blocked A375 cell migration and invasion in vitro which was associated with the downregulation of MMP‑9 and MMP‑2. Finally, intragastric administration of LD suppressed tumor growth in the mouse xenograft model of murine melanoma B16F0 cells. These results suggest that LD may be a potential drug for human melanoma treatment by inhibiting proliferation, inducing apoptosis via the mitochondrial pathway and blocking cell migration and invasion.

Neutralization of MMP-2 protects Staphylococcus aureus infection induced septic arthritis in mice and regulates the levels of cytokines

Matrix metalloproteinases (MMPs) are crucial players in Staphylococcus aureus mediated synovial tissue destruction in the pathogenesis of septic arthritis. Bacterial insult increases proteolytic matrix fragments by activated chondrocytes and synovial fibroblasts leading to induction of matrix metalloproteinases. Tissue destruction via MMPs induced by bacterial products, necrotic tissues and proinflammatory cytokines have been reported. Cytokines like TNF-α, IL-1β released from host cells in response to S. aureus infection promote cartilage degradation by stimulating the production of MMPs. Antibiotic treatment can eradicate invading bacteria but elevated levels of cytokines and cytokines induced MMPs activation lead to progressive and devastating bone and cartilage destruction even after bacterial clearance. Like other MMPs, MMP-2 also contributes to extracellular matrix degradation in different types of arthritis. Release of certain pro inflammatory cytokines can also be regulated by MMP-2 activation leading to further tissue destruction. The role of MMP-2 in the pathogenesis of S. aureus infection induced septic arthritis and its influence on cytokines regulation needs further investigation. Whether neutralization of MMP-2 provides protection against Staphylococcus aureus infection induced septic arthritis in mice is an obvious question. Here we reported that neutralization of MMP-2 during S. aureus infection induced septic arthritis might be beneficial for preventing infection induced extracellular matrix destruction thereby decreasing bacterial burden in synovial tissues and regulating inflammatory cytokines in arthritic mice.

Comparison of Arthroscopic Lavage and Needle Lavage Techniques, and Lavage Volume on the Recovery of Colored Microspheres From the Tarsocrural Joints of Cadaver Horses

OBJECTIVE

To quantify recovery of colored microspheres from normal cadaver tarsocrural joints using arthroscopic or needle lavage with 1-5 L of fluid.

STUDY DESIGN

Ex vivo experimental study.

ANIMALS

Adult Quarter Horse cadavers (n = 8).

METHODS

After euthanasia, 1.5 × 10(6)  colored microspheres were injected into each tarsocrural joint. Each joint was randomly assigned to receive lavage (5 L 0.9% NaCl) with an arthroscope (dorsomedial arthroscope and dorsolateral egress cannula) or three 14 g needles (dorsomedial ingress, dorsolateral, and plantarolateral egress). Egress fluid from each liter was collected separately over time and the number of microspheres present in each recovered liter determined by spectrophotometry.

RESULTS

A significant interaction was present between treatment group and liter of fluid (P < .01). The number of microspheres recovered in the first liter of lavage fluid was significantly higher in the needle lavage group than in the arthroscopic lavage group (P < .01). For both groups, the number of microspheres recovered in the first liter of lavage fluid represented a majority of the total microspheres collected and was significantly different from each subsequent liter collected (P < .01). The number of microspheres recovered did not differ between liters 2, 3, 4, and 5 within or between treatment groups.

CONCLUSION

In this model, tarsocrural lavage with three 14 g needles was more effective at removing colored microspheres from the joint than arthroscopic lavage, suggesting that the number or placement of portals present may be more important than portal size and flow rate. No difference in microsphere recovery was seen with lavage volumes >1 L.

Andrographolide Exerts Chondroprotective Activity in Equine Cartilage Explant and Suppresses Interleukin-1 β -Induced MMP-2 Expression in Equine Chondrocyte Culture

Cartilage erosion in degenerative joint diseases leads to lameness in affected horses. It has been reported that andrographolide from Andrographis paniculata inhibited cartilage matrix-degrading enzymes. This study aimed to explore whether this compound protects equine cartilage degradation in the explant culture model and to determine its effect on matrix metalloproteinase-2 (MMP-2) expression, a matrix-degrading enzyme, in equine chondrocyte culture. Equine articular cartilage explant culture was induced by 25 ng/mL interleukin-1β, a key inducer of cartilage degeneration, in cultures with or without andrographolide ranging from 10 to 50 μM. After 3–21 days, they were analyzed for the markers of cartilage degradation. It was found that interleukin-1β increased the release of sulfated glycosaminoglycans and hyaluronan from the explants into the culture media consistently with the decrease in uronic acid and collagen content in the cartilage explants. These catabolic effects were inhibited when cotreated with interleukin-1β and andrographolide. In primary equine chondrocytes, andrographolide suppressed interleukin-1β-induced MMP-2 mRNA expression and MMP-2 activity in the culture medium. These results confirmed the in vitro potent chondroprotective activities of this compound which were performed in cartilage explants and on a cellular level. These may indicate the application of andrographolide for therapeutic use in equine degenerative joint diseases.

Plasma matrix metalloproteinase activity in horses after intravenous infusion of lipopolysaccharide and treatment with matrix metalloproteinase inhibitors

OBJECTIVE

To establish an in vivo method for matrix metalloproteinase (MMP)-2 and MMP-9 induction in horses via IV administration of lipopolysaccharide (LPS) and to evaluate the ability of doxycycline, oxytetracycline, flunixin meglumine, and pentoxifylline to inhibit equine MMP-2 and MMP-9 production.

ANIMALS

29 adult horses of various ages and breeds and either sex.

PROCEDURES

In part 1, horses received an IV administration of LPS (n = 5) or saline (0.9% NaCl) solution (5). Venous blood samples were collected before and at specified times for 24 hours after infusion. Plasma was harvested and analyzed for MMP-2 and MMP-9 activities via zymography. In part 2, horses received doxycycline (n = 5), oxytetracycline (5), flunixin meglumine (5), or pentoxifylline (4) before and for up to 12 hours after administration of LPS. Plasma was obtained and analyzed, and results were compared with results from the LPS-infused horses of part 1.

RESULTS

Administration of LPS significantly increased MMP-2 and MMP-9 activities in the venous circulation of horses. All MMP inhibitors significantly decreased LPS-induced increases in MMP activities but to differing degrees. Pentoxifylline and oxytetracycline appeared to be the most effective MMP-2 and MMP-9 inhibitors, whereas doxycycline and flunixin meglumine were more effective at inhibiting MMP-2 activity than MMP-9 activity.

CONCLUSIONS AND CLINICAL RELEVANCE

IV administration of LPS to horses caused increased venous plasma activities of MMP-2 and MMP-9. These MMP activities were reduced by pentoxifylline and oxytetracycline, suggesting that further evaluation of these medications for treatment and prevention of MMP-associated diseases in horses is indicated.

Expression levels of matrix metalloproteinase (MMP)-9 and its specific inhibitor TIMP-1, in septic and aseptic arthritis of the knee

PURPOSE

In cases of septic knee arthritis, there is excess of matrix metalloproteinases (MMPs) over tissue inhibitors of metalloproteinases (TIMPs), due to enhanced expression and activation that are induced by bacteria in comparison with rheumatic or degenerative arthritis. The aim of this study was to explore the expression levels of synovial gelatinase MMP-9 and its specific inhibitor TIMP-1 in septic and aseptic arthritis and their potential use as additional aids to clinical investigation.

METHODS

Gelatin zymography and western blot analysis were applied in effusions from knees of the patients with septic (SA-10 patients), rheumatic (RA-10 patients) and osteoarthritis (OA-10 patients).

RESULTS

Zymographic analysis revealed that all samples contained latent MMP-2 activity, albeit activated MMP-2 appeared in more of the septic than aseptic effusions. MMP-9 was not detected in osteoarthritic synovial fluid samples. Only trace amounts of MMP-9 activity were detected in 4 of 10 patients with RA, whereas higher MMP-9 levels were evident in all samples from SA (P = 0.0241). In immunoblotting assays, samples from SA showed significantly higher levels of MMP-9 compared with samples from RA (P = 0.0052), confirming zymographic results. Although no significant difference in TIMP-1 levels was observed, the estimated MMP-9/TIMP-1 ratio of septic effusions was significantly higher compared with aseptic ones (P = 0.0029).

CONCLUSIONS

The data presented suggest enhanced expression and activation of MMP-9 in septic native knee arthritis compared with aseptic. The presence of high levels of MMP-9 with concomitantly increased MMP-9/TIMP-1 ratio and activated gelatinases in effusions, independent of neutrophilic counts, may be indicative for infection.

Preventive administration of juanbi capsules for knee osteoarthritis: effects on serum MMP-2 and MMP-9 levels and cartilage repair

OBJECTIVE

To explore the mechanism of action of Juanbi Capsules, a Chinese medicine for invigorating the kidney and replenishing qi, in preventing osteoarthritis of the knee in rabbits.

METHODS

Seventy-two 4-month-old, Japanese long-eared white rabbits were randomly divided into 6 groups: control (group A), model (group B), Chinese drug; high-dose (group C), Chinese drug; mid-dose (group D), Chinese drug; low-dose (group E), and drug control (group F). With the exception of the rabbits in group A, each rabbit was subjected to plaster cast fixation for 6 weeks to induce osteoarthritis. In addition, rabbits were administrated with an intragastric injection of the Chinese drug (groups C, D and E) or an aminoglucose hydrochloride capsule (group F) for 4 weeks. Blood was drawn from the central ear artery for serum MMP-2 and MMP-9 concentrations, and the knee joint cartilage was harvested for gross observation and light microscopy.

RESULTS

There were significant differences in serum MMP-2 and MMP-9 concentrations between group B and groups C, D and E (P < 0.05), with no significant differences between groups D and F. Histological results showed various changes in tissue staining with treatment, with osteophyte and bone cyst formation, and superficial erosion in the articular surface of the cartilage; in some cases, the defect reached the mid-layer of the cartilage, and these changes were lower than those in the model group.

CONCLUSION

Juanbi Capsules assist in preventing osteoarthritis in the rabbit, possibly by decreasing serum MMP-2 and MMP-9 levels.

Topical dermal application of essential oils attenuates the severity of adjuvant arthritis in Lewis rats

This study was aimed at examining the effect of an ointment containing essential oils (EO) on the severity of adjuvant arthritis (AA), an experimental model of human rheumatoid arthritis (RA), in Lewis rats and to define the underlying mechanisms. At the onset of AA, the rats received topical application twice daily of an ointment containing 20% EO or placebo ointment. The synovial fluid (SF) and synovium-infiltrating cells (SIC) of rats were tested for pro-inflammatory cytokines TNF-α and IL-1β. The hind paws and skin were examined histologically. The activity/level of matrix metalloproteinases (MMPs) and anti-mycobacterial heat-shock protein 65 (Bhsp65) antibodies were tested. Arthritic rats treated with ointment containing EO developed less severe clinical arthritis compared with the controls, and this activity was attributable to EO and not to the carrier oil. The levels of TNF-α and IL-1β, and the activity of MMPs in SF and SIC-lysate were significantly reduced in EO-treated arthritic rats compared with the controls. However, the levels of anti-Bhsp65 antibodies were unaffected by treatment. Thus, topical dermal delivery of EO-containing ointment down-modulates the severity of AA in Lewis rats by inhibiting defined mediators of inflammation. Such ointments should be tested in patients with RA and other arthritic conditions.

Comparative study of the properties of tendinocytes derived from three different sites in the equine superficial digital flexor tendon

This aim of this study was to determine the characteristic differences in tendinocytes derived from three sites of the equine superficial digital flexor tendon (SDFT)-proximally the myotendinous junction (MTJ), mid-metacarpal (mM) and osteotendinous junction (OTJ)-in morphology, proliferation, and ability for synthesis of collagen and matrix metalloproteinases (MMPs). Little difference was observed in cell proliferation. Addition of tumor necrosis factor (TNF) alpha to the culture medium resulted in increased collagen synthesis by tendinocytes from all three sites. The amount of collagen synthesized by tendinocytes derived from the mM and OTJ was much larger than that synthesized by untreated tendinocytes. A collagen zymogram revealed that proMMP-13 synthesis was increased towards the distal site. However, TNFalpha treatment resulted in a significant decrease in the amount of proMMP-13 synthesized by tendinocytes from all three sites. On the other hand, a gelatin zymogram showed that the synthesis level of proMMP-9 tended to decrease towards the distal site, but there was little difference between synthesis levels of proMMP-9 before and after TNFalpha treatment. These results indicated that tendinocytes in the same tendon have different characteristics and that these characterisities would reflect the function of tendinocytes in vivo. Also, the isolated tendinocytes provided much information on the characteristics and properties of tendons for the ECM turnover system and on the responsiveness of tendinocytes to complex inflammatory responses in a tendinopathy condition.