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- Author or Editor: John P. Caron x
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Abstract
Objective—To determine effects of glucosamine (GLN) and chondroitin sulfate (CS) on expression of genes encoding putative mediators of osteoarthritis in bovine cartilage explants cultured for 2 weeks.
Sample Population—Articular cartilage explants harvested from carpal joints of 4 Holstein steers after slaughter.
Procedures—Cartilage disks were treated as follows: fetal bovine serum only (control treatment), human recombinant interleukin (IL)-1β (50 ng/mL; IL-1 treatment), GLN (5 μg/mL) with addition of CS (20 μg/mL; GLN-CS treatment), and human recombinant IL-1β (50 ng/mL) with addition of GLN and CS (IL-1–GLN-CS treatment). Media were analyzed for nitric oxide and prostaglandin E2 (PGE2) release. Explants were subjected to quantitative real-time PCR analysis; expressions of mRNA for inducible nitric oxide synthase, cyclooxygenase-2, microsomal prostaglandin E synthase 1, matrix metalloproteinase (MMP)-3 and -13, aggrecanase-1 and -2, tissue inhibitor of metalloproteinase (TIMP)-3, type II collagen, and aggrecan were assessed.
Results—IL-1–GLN-CS and GLN-CS treatments decreased nitrite release, compared with IL-1 treatment; IL-1–GLN-CS treatment decreased IL-1–induced PGE2 release. Expressions of inducible nitric oxide synthase, cyclooxygenase-2, and microsomal prostaglandin E synthase 1 mRNA were abrogated by GLN-CS and IL-1–GLN-CS treatments. Interleukin-1–induced mRNA expressions of proteolytic enzymes were diminished by IL-1–GLN-CS treatment. Compared with control treatment, GLN-CS treatment decreased MMP-3 and aggrecanase-2 mRNA expression. Transcripts of TIMP-3 were increased by IL-1–GLN-CS treatment, compared with IL-1 treatment. Genes encoding type II collagen and aggrecan on day 14 were upregulated by GLN-CS and IL-1–GLN-CS treatments, compared with control treatment.
Conclusions and Clinical Relevance—Treatment with GLN and CS consistently downregulated mRNA expression for inflammatory mediators and matrix degrading enzymes while increasing TIMP-3 transcripts.
Abstract
Objective—To determine the effects of glucosamine (GLN) and chondroitin sulfate (CS), at concentrations attainable in vivo, on expression of genes encoding proteolytic enzymes, enzyme inhibitors, and macromolecules of articular cartilage in interleukin-1(IL- 1)–challenged bovine cartilage explants.
Sample Population—Articular cartilage explants harvested from 9 steers.
Procedures—Cartilage explants were exposed to media containing 10% fetal bovine serum (FBS) only, IL- 1 (50 ng/mL), IL-1 with GLN (5 µg/mL), IL-1 with CS (20 µg/mL), or IL-1 with GLN and CS for 24 and 48 hours. Cartilage was frozen, and RNA was extracted. Gene expression of matrix metalloproteinases (MMPs)-2, -3, -9, -13, and -14; aggrecanases (Aggs)-1 and -2; tissue inhibitors of metalloproteinases (TIMPs)-1, -2, and -3; and type II collagen and aggrecan were assessed with quantitative real-time polymerase chain reaction.
Results—Upregulated MMP-3, MMP-13, and Agg-1 transcripts at 24 hours were repressed by the GLN and CS combination by at least approximately 6-fold. Glucosamine was effective in suppressing IL-1–induced mRNA expression of MMP-13, Agg-1, and Agg-2, whereas CS was effective in decreasing IL-1–induced MMP-13 transcript at 24 hours. At 48 hours, GLN and CS added separately and in combination significantly abrogated Agg-1 and Agg-2 gene induction. The combination also decreased IL-1–stimulated MMP-13 transcript.
Conclusions and Clinical Relevance—GLN and CS, at concentrations that are within the range measured in synovial fluid and blood after oral administration, may regulate expression of matrix degrading enzymes and their inhibitors at the transcriptional level, providing a plausible mechanism for their purported chondroprotective properties. (Am J Vet Res 2005;66:1870–1876)
Summary
Medical records of 51 horses with epiglottic entrapment were reviewed, and the outcome after surgical treatment was evaluated by use of results from a survey of owners and from race records. Horses with epiglottic entrapment and no additional problem (uncomplicated) of the nares, nasal passages, pharynx, or larynx (upper airway) that were treated by transoral axial division (group 1) or resection via laryngotomy (group 2), and horses with epiglottic entrapment complicated by an additional upper airway abnormality (group 3) were compared. The cost of treatment, duration of hospitalization, time to first race start after surgery, and complication rate were significantly (P < 0.05) less in horses in group 1, compared with those in horses of group 2. Owner survey indicated that a significantly greater percentage (82%) of horses in group 1 had a successful outcome after transoral axial division, compared with that (27%) of horses in group 2. Analysis of race records indicated that performance was similar between horses in groups 1 and 2, and significantly more horses with an additional upper airway lesion (group 3) failed to return to racing than did horses with uncomplicated epiglottic entrapment (groups 1 and 2). Transoral axial division of the aryepiglottic fold is recommended as an appropriate treatment for uncomplicated epiglottic entrapment. Resection via laryngotomy should be reserved for treatment of epiglottic entrapment associated with excessively thick and scarred aryepiglottic folds and for intermittent epiglottic entrapment in horses for which surgical correction is deemed appropriate. Horses with epiglottic entrapment complicated by previous aryepiglottic fold surgery or another upper airway abnormality, particularly epiglottic deformity or dorsal displacement of the soft palate, should receive a less favorable prognosis for return to athletic performance.
SUMMARY
Objective
To evaluate the influence of exogenous hyaluronan (HA) on in vitro synthesis of HA and collagenase by equine synoviocytes from normal and inflamed joints.
Animals
9 adult horses.
Procedure
Synoviocytes for culture were taken from the middle carpal joint of 3 horses with normal joints (control) and 6 horses with osteochondral fractures (principal). Synoviocytes were propagated in monolayer cultures and were incubated with 3 commercial HA products at concentrations of 0, 200, 400, and 1,500 μg/ml. Newly synthesized HA was radiolabeled with [3H]glucosamine and quantified by cetylpyridinium chloride precipitation and liquid scintillation counting. The hydrodynamic size of radioactive HA was determined by high-performance liquid chromatography, and collagenase activity was evaluated by use of a quantitative radioactive collagen film assay.
Results
Exogenous HA influenced neither the rate of synthesis nor the hydrodynamic size of the newly produced HA by control or principal cell cultures. Culture supernatants from abnormal synovium, exposed to 400 and 1,500 μg of exogenous HA/ml, contained significantly more collagenase activity than did those exposed to lower concentrations.
Conclusion
Although HA is thought to have beneficial effects in equine arthropathies, the principal mechanisms of action of HA do not appear to be stimulation of synthesis of HA of augmented molecular weight or marked inhibition of collagenase synthesis. (Am J Vet Res 1998;59:888–892)
Abstract
Objective
To determine whether matrix metalloprotease 13 (MMP-13; collagenase 3) is produced by equine chondrocytes and to investigate modulation of its expression by recombinant human interleukin β (rhIL-1β) and corticosteroids.
Procedure
Equine chondrocytes in monolayer culture were stimulated with rhIL-1β. Total RNA was extracted, purified, and reverse transcribed into DNA. Using appropriate primers, a putative MMP-13 fragment was amplified by polymerase chain reaction, and cloned into a bacterial vector. The resultant fragment was purified and sequenced, then was used to prepare a digoxigenin-labeled cRNA probe. Monolayer cultures of first-passage chondrocytes were treated with rhIL-1β in the presence or absence of dexamethasone (10-6 M) or methylprednisolone acetate (10-9 M to 10-5 M), in addition to positive and negative controls. Cellular RNA was extracted and resolved on agarose gels and subjected to northern blot analysis, using the equine MMP-13 probe.
Results
Reverse transcriptase-polymerase chain reaction enabled isolation of a 0.6-kb fragment of equine MMP-13 cDNA that had 93% homology with the human MMP-13 cDNA sequence. rhIL-1 significantly stimulated MMP-13 expression in the chondrocytes. Methylprednisolone acetate inhibited the stimulatory effects of rhIL-1 in dose-dependent manner that was statistically significant at 10-5 M.
Conclusions
Novel information was gained on the existence of MMP-13 and its expression in equine chondrocytes, which suggests a possible role for this enzyme in matrix degradation in horses with arthritis. (Am J Vet Res 1996;57:1631–1634)
Abstract
Objective
To compare the apparent viscosity of normal synovial fluid of the mid-carpal, tibiotarsal, and interphalangeal joints of horses.
Design
Viscosity evaluation over a range of shear rates was used to characterize the apparent viscosity of synovial fluids from the 3 joints.
Animals
60 clinically normal adult horses.
Procedure
Viscosity data for synovial fluid samples were obtained over a shear rate range of 10 to 250/s and apparent viscosity was calculated at 50, 100, 150, 200, and 250/s. Effect of shear rate on apparent viscosity was determined, using a two-way ANOVA, with significant differences tested, using a Tukey's test at a significance level of P < 0.05.
Results
Synovial fluid from all these joints indicated shear thinning behavior: decreased apparent viscosity with increased shear rate. Apparent viscosity of synovial fluid from the 3 joints was not significantly different over the shear rate range of 50 to 250/s.
Conclusion
Results of this study indicate that the apparent viscosity of the distal interphalangeal joint is not less than that of other joints, as has been reported.
Clinical Relevance
The observation of decreased synovial fluid viscosity of distal interphalangeal joint fluid should be considered as suggestive of joint disease. (Am J Vet Res 1996;57:879–883)
Abstract
Objective—To determine the clinical characteristics and outcome of foals with septic osteitis of the distal phalanx.
Design—Retrospective case series.
Animals—22 foals.
Procedures—Information obtained from medical records included signalment; clinical, laboratory, and radiographic findings; treatment method; and outcome. Foals included in the study had lameness referable to the foot, radiographic evidence of localized lysis or focal loss of bone density of the distal phalanx, and suppurative discharge or necrosis of the affected bone evident at surgery. Foals with a history or evidence of penetrating wounds or subsolar abscessation were excluded.
Results—Mean age of foals at initial evaluation was 40.8 days (range, 3 to 122 days). Twenty-one (95%) foals had lameness as the primary complaint. Lesions consistent with septic osteitis of the distal phalanx localized to specific areas of the bone on the basis of radiographic and surgical findings were located on the solar margin or toe (14/22 [64%]), extensor process (5/22 [23%]), and palmar or plantar process (3/22 [13%]). Hind limbs (18/26 [69%] affected limbs) were more frequently affected. Two foals had > 1 affected limb, 2 had additional sites of osteomyelitis, and 4 had concurrent septic arthritis. Surgical debridement and regional antimicrobial perfusion were performed during general anesthesia. Extensor process lesions were not debrided. Nineteen of 22 (86%) foals survived to be discharged from hospital, and 16 horses reached racing age. Eleven of 16 had race starts, of which 8 had official race starts and 3 had unofficial race starts.
Conclusions and Clinical Relevance—Septic osteitis of the distal phalanx should be considered as a source of lameness in foals with signs referable to the foot and does not necessarily preclude a career in racing. Although infection may occur secondary to bacterial penetration of the hoof or sole, the distal phalanx should also be considered as a potential site for hematogenous septic arthritis or osteomyelitis in foals.
