Equine Synovial Fluid Research Articles

Transforming growth factor-β1 concentrations in equine synovial fluid

Summary A commercial assay for human TGF-β1 was validated for use on equine synovial fluid and serum. This assay was then used to determine concentrations of TGF-β1 in synovial fluid samples from 109 metacarpophalangeal joints of horses with varying age, gender, and joint condition. No difference in concentration was found between geldings and females. A difference (p=.04) was found between young horses (≤48 months, 1101 pg/ml) and old horses (≥120 months, 863 pg/ml), and between horses with visibly normal joints and those with severely diseased joints (885 versus 1002 pg/ml, p=0.01). These findings suggest concentrations of TGF-β1 are elevated in joints from younger horses and joints with gross evidence of disease.

Hyaluronate and large molecular weight proteoglycans in synovial fluid from horses with various arthritides

Abstract Objective To investigate the presence of large molecular weight (MW) proteoglycans (PG) and hyaluronate (HA) in synovial fluid (SF) from horses with various arthritides and from control joints. Design Horses with acute (< 2 weeks) or chronic (> 4 weeks) lameness were examined by clinical examination, intrasynovial anesthesia, radiography, arthroscopy, and SF analysis. Joints were grouped on the basis of diagnosis: acute traumatic arthritis, chronic traumatic arthritis (with a subgroup of degenerative joint disease), intra-articular fracture, and infectious arthritis. Animals 31 horses with arthritis and 9 control horses; altogether 43 SF samples were analyzed. Procedure High-performance liquid chromatography was used to assess HA and large MW PG in SF samples. Results. A PG peak was identified in 8 of 23 SF samples of joints with chronic traumatic arthritis, 4 of which had no or minimal abnormal radiographic findings but mild articular cartilage fibrillation detected by arthroscopy, and in 3 joints with intra-articular fracture and 1 with resolving infectious arthritis, but not in joints with acute traumatic arthritis or in control joints. There was significant difference (P < 0.01) in mean (± SEM) HA concentration between control joints and joints with chronic traumatic arthritis (0.32 ± 0.04 g/L; n = 9 vs 0.18 ± 0.01 g/L; n = 23). Conclusions Large MW PG fragments are released into equine SF in the course of articular disease and can be detected simultaneously with HA by high-performance liquid chromatography. Clinical Relevance The SF HA concentration can be used as diagnostic marker for chronic traumatic arthritis. However, SF PG or other marker cannot be used for diagnosing or monitoring degenerative joint disease. (Am J Vet Res 1996;57:932–937)

Detection of bacteria in equine synovial fluid by use of the polymerase chain reaction.

Equine synovial fluid aliquots were inoculated with Salmonella enteritidis, Escherichia coli, Actinobacillus equuli, Staphylococcus aureus, and Streptococcus zooepidemicus to obtain approximate concentrations of 1000, 100, 10, and 1 colony forming U/mL. Synovial fluid aliquots were also inoculated with an unquantitated inoculum of Bacteroides fragilis and Clostridium perfringens. Inoculated synovial fluid was incubated in trypticase-soy broth or Columbia broth for approximately 12 hours. Then aliquots were removed for DNA extraction and polymerase chain reaction (PCR) analysis for detection of a 531 base-pair segment of bacterial DNA corresponding to a region of the 16S ribosomal gene. Duplicate samples of inoculated synovial fluid were prepared for microbial culture. Bacteria were detected in all samples inoculated with bacteria but not in control synovial fluid samples. Under experimental conditions there was no difference between microbial culture and PCR analyses for detection of bacteria. Experimentally, PCR was able to detect bacteria in synovial fluid within 24 hours of inoculation.

Inflammatory mediators in equine synovial fluid

Enzyme immunoassay for prostaglandin E2 (PGE2), and radioimmunoassays for prostaglandin F2 alpha (PGF2 alpha), 6-keto-PGF1 alpha, and leukotriene B4 (LTB4) were performed on synovial fluid from normal middle carpal joints of 10 horses, and from 30 middle carpal or antebrachiocarpal joints of horses affected by degenerative joint disease and chip fractures to compare the concentrations of inflammatory mediators. Significantly greater concentrations of PGE2 were detected in fluid from affected than from control joints, but there were no significant differences in the mean concentrations of PGF2 alpha, 6-keto-PGF1 alpha, and LTB4.

Free radical oxidation products in plasma and synovial fluid of horses with synovial inflammation

Free radical oxidation products, namely conjugated dienes, ultraviolet fluorescence (excitation 325 nm, emission 395 nm) and visible fluorescence (excitation 360 nm, emission 460 nm) were measured in equine synovial fluid exposed to free radicals in vitro and in the plasma and synovial fluids of horses with synovial effusions. The synovial effusions were induced by intra-articularly administered carrageenin (0.3 ml, 1%), which rarely resulted in clinical lameness. The free radicals were generated in vitro by mixtures of iron and ethylene diamine tetra acetate (Fe/EDTA) or mixtures of hypoxanthine and xanthine oxidase (HX/XO). The conjugated diene concentrations and intensity of ultraviolet fluorescence were negligible in plasma and synovial fluid specimens. No increase resulted from incubation of synovial fluids with either a free radical generating system or as a result of the induced inflammation. The intensity of visible fluorescence did not increase in specimens incubated with Fe/EDTA. However, the intensity of visible fluorescence increased in specimens incubated with HX/XO, in synovial effusions induced by carrageenin, in plasma and in synovial fluids aspirated from saline injected controls. The results indicate that the intensity of visible fluorescence of equine synovial fluid increases after exposure to free radicals and during synovitis in the horse, suggesting a possible role for free radicals in the pathogenesis of equine inflammatory joint disease.

Inhibition of interleukin‐1 activity by equine synovial fluid

The presence, in equine synovial fluid, of inhibitors of interleukin-1 (IL-1) activity has been investigated by means of an assay involving IL-1-mediated production of PGE2 by synovial cells. Inhibitors of IL-1 alpha and IL-1 beta were identified in normal synovial fluid and synovial fluid from two horses with early joint disease. Inhibitors of IL-1 alpha were also present in synovial fluid from two horses with long-standing joint disease. However, IL-1 beta inhibitory activity was not present in fluid from the horses with more chronic joint disease. The effect appeared to be specific for IL-1, and not a direct action on PGE2 production, as synovial fluid had no effect on lipopolysaccharide-mediated PGE2 production. It is suggested that the inhibitory activity may be involved physiologically in the control of IL-1 activity in the joint, and the loss of IL-1 inhibition may be at least as important biologically as increased production of IL-1.

Anti‐inflammatory drugs inhibit degradation of equine synovial fluid induced by free radicals

Anti‐inflammatory drugs inhibit degradation of equine synovial fluid induced by free radicals

Effect of Palosein (superoxide dismutase) and catalase upon oxygen derived free radical induced degradation of equine synovial fluid

The effect of oxygen derived free radicals (ODFR) upon the specific viscosity of equine synovial fluid was studied. ODFR were generated either by a mixture of ferrous iron and EDTA (Fe/EDTA) or by a mixture of hypoxanthine and xanthine oxidase (HX/XO). Incubation of the synovial fluid with both free radical generating systems decreased its specific viscosity. When the synovial fluid was incubated with Fe/EDTA the specific viscosity of the synovial fluid was reduced rapidly. By 2 mins, it was 53 +/- 3 per cent of the original specific viscosity and by 30 mins it was reduced to 39 +/- 5 per cent. In the HX/XO system, the specific viscosity was 75 +/- 4 per cent of the original specific viscosity at 10 mins and by 50 mins it was reduced to 55 +/- 3 per cent. Palosein (superoxide dismutase) was an effective inhibitor of the free radical induced reduction of the viscosity of the synovial fluid when the free radicals were generated with HX/XO but not with Fe/EDTA. Catalase was moderately effective as an inhibitor of reduction in specific viscosity of the synovial fluid when the free radicals were generated by either system. Only minor synergy resulted when mixtures of Palosein and catalase were tested for inhibition of Fe/EDTA induced reduction in the specific viscosity of equine synovial fluid. The results indicate that Palosein may protect equine synovial fluid from the effects of the superoxide radical (O2-) but not from the hydroxyl radical (OH.).(ABSTRACT TRUNCATED AT 250 WORDS)

Improved colorimetric determination of high-molecular weight hyaluronic acid from synovial fluids

A method is presented depending on the metachromic shift of a carbocyanine dye (“Stains-all”) in the presence of high molecular weight hyaluronic acid. Although this colorimetric reaction itself is not new, progress has been made in elaborating a technique which, in most cases, does not require any pretreatment of the original biological sample (synovial fluid) except appropriate dilution. The method is relatively free of interferences by other substances. The kinetics (time-absorption modes) at defined wavelengths have been demonstrated to be a valid tool for identifying the target macromolecule. The reliability of the method has been demonstrated with equine synovial fluids and with pure hyaluronate from rooster comb as reference substance.

Na-hyaluronate molecular size variations in equine and human arthritic synovial fluids and the effect on phagocytic cells

Na-hyaluronate molecular size variations in equine and human arthritic synovial fluids and the effect on phagocytic cells

LDH and LDH Isoenzymes of Synovial Fluid in the Horse

LDH is an intracellular enzyme, which when cells degenerate is released to the extracellular spaces and body fluids. Cells and organs in the mammalian body differ from each other with respect to their LDH isoenzyme patterns. These circumstances have led to the use of LDH isoenzyme determinations in laboratory diagnostic work. In the present investigation total LDH activity and LDH isoenzyme distribution in equine synovial fluid from healthy joints, joints with serous arthritis, osteochondrosis dissecans and arthrosis, were determined. The fluids from the diseased joints differed from normal synovial fluid with respect to total LDH activity, and the different joint diseases each seemed to give rise to a characteristic isoenzyme pattern. In order to examine possible sources of the increased LDH activity and altered isoenzyme patterns, blood plasma, red and white blood cells, synovial membrane and articular cartilage were also studied. It was found that LDH4 and LDH5 were present in high amounts in articular cartilage, and an increase in these isoenzymes was the most characteristic feature in synovial fluid from joints with arthrosis. The results were discussed in view of possible diagnostic value of isoenzyme determinations on synovial fluid.

Viscosity of Equine Synovial Fluid

Synovial fluid samples from 51 light horses were examined with respect to their rheologie properties. The analyses were made with a Rotovisco RV3 rotational viscosimeter. Samples from carpal, stifle and hock joints and from healthy joints, joints with synovitis and joints with infectious arthritis were studied. The analyses showed that synovial fluids from both healthy and diseased joints have complex rheologie properties. In most samples the viscosity varied with the shear rates, the main exceptions being synovial fluids from joints with infectious arthritis. Flow curves (flow behaviour), rather than single observations on viscosity, were considered to be representative for the synovial fluids examined.