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Abstract

Objectives

To use lipopolysaccharide (LPS) to create synovitis in the midcarpal joint of ponies, and to assess the morphologic, histochemical, and immunohistochemical effects of synovitis on articular cartilage of the third carpal bone.

Animals

2- to 3-year-old ponies, 6 control (group 1) and 6 treated (group 2).

Procedure

Synovitis was induced in 1 midcarpal joint of group-2 ponies by intra-articular injections of LPS (0.02 μg/kg of body weight), morphine (0.1 mg/kg), and saline solution (group 2a) and morphine and saline solution alone in the contralateral midcarpal joint (group 2b). Articular cartilage sections and attached synovial membrane from the third carpal bones were examined by immunohistochemical distribution of interleukin 1β, tumor necrosis factor (TNF)-α, TNF receptors (P55, P75) and 3-B-3(–) epitopes, and by localization of proteoglycans (metachromatic staining). Proteoglycan extracts were assessed by metachromatic staining or western blotting and immunohistochemical staining, using anti-3-B-3 antibodies.

Results

Enhanced immunoreactivity for the cytokines and receptors was found in inflamed synovial membrane and noncalcified cartilage (group 2a more than 2b). Metachromasia of the noncalcified cartilage was greater in group-1 than in group-2a and group-2b specimens. In group 2a, chondrocyte hypertrophy and enhanced immunoreactivity for 3-B-3(–) epitope in areas of increased cytokine immunoreactivity suggested possible phenotypic change of the chondrocytes in response to synovitis. Immunohistochemical analysis by western blotting of proteoglycan extracts indicated strong 3-B-3(–) epitope immunolocalization in group-2a, weaker staining in group-2b, and barely detectable stain in group-1 specimens, which correlated with in situ immunolocalization.

Conclusions

Intra-articular administration of LPS may be used to induce a synovial environment conducive to increased immunoreactivity of interleukin 1β, TNF-α, and its receptors in equine synovial membrane and articular cartilage. These cytokines may be involved in the early phenotypic change of chondrocytes that is believed to occur in osteoarthritis and is characterized in this study by enhanced 3-B-3(–) epitope immunoreactivity and chondrocyte hypertrophy. (Am J Vet Res 1996;57:1080–1093)

Free access
in American Journal of Veterinary Research

in basal cell culture media (Dulbecco modified Eagle medium–Ham F12, 1:1) devoid of hormonal and growth factor supplements. The following recombinant equine cytokines were used: TNF-α, IL-2, IL-4, IL-5, IL-6, IL-8, and IL-10. k,l After 48 hours

Full access
in American Journal of Veterinary Research

. 7 Circulating concentrations of inflammatory molecules, including acute phase proteins and inflammatory cytokines such as TNFα, are high in obese humans, with higher concentrations seen in obese patients with insulin resistance and type II diabetes

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in American Journal of Veterinary Research

Abstract

Objective

To develop and define a model of acute synovitis/capsulitis in the equine metacarpophalangeal joint (fetlock) to study clinical effects of diagnostic or therapeutic procedures.

Animals

5 adult Standardbreds.

Procedure

Polyvinyl alcohol foam particles were injected into the left front fetlock of horses; the right front fetlock was used as a control. Horses were examined clinically and for lameness on a regular basis. Blood samples were taken to measure routine variables. Synovial fluid samples were collected from both fetlocks, and macroscopic, microscopic, and biochemical variables were measured. The effects of local diagnostic nerve blocks and intra-articular anesthesia of the fetlock on ensuing lameness were determined on days 2 and 3. After macroscopic evaluation at necropsy, histologic examination was performed on the fetlock cartilage and capsule.

Results

Changes in synovial fluid variables included increased TNF-α and matrix metalloproteinases values and in other indicators of acute inflammation. With respect to application of local nerve blocks, lameness decreased most after a combination of metacarpal and palmar nerve blocks, whereas lameness could only partially be blocked by intra-articular anesthesia. At necropsy, mild chronic inflammation of the synovium and deeper layers of the joint capsule was found; polyvinyl alcohol particles had been incorporated into the joint capsule. There was no evidence of articular cartilage damage.

Conclusions

Injection of polyvinyl alcohol foam particles induces transient synovitis/capsulitis in the fetlock, mimicking clinical joint disorders. The model does not seriously affect the horse's long-term well-being. Such model serves well for studying the effect of diagnostic or therapeutic procedures. (Am J Vet Res 1998;59:978–985)

Free access
in American Journal of Veterinary Research

humans in which cytokines (IL-1, IL-6, IL-8, TNF-α, and TGF-β) have been evaluated in an effort to categorize and quantify the degree of joint inflammation and to provide a prognosis. The interactions of these cytokines are integrally involved in acute

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in American Journal of Veterinary Research

product was measured at a wavelength of 550 nm by use of an ELISA plate reader. i Assessment of procoagulant activity and TNF-α production induced by equine mononuclear cells exposed to BWE —Five hundred microliters of equine mononuclear cells

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in American Journal of Veterinary Research

if MHC class II expression is affected by the recipient. In vitro exposure of MSCs to inflammatory signals such as lipopolysaccharide or IL-1β increases production of proinflammatory cytokines (TNF-α, IL-1β, IL-6, and IL-8). 17 It is unknown whether

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in American Journal of Veterinary Research

osteoarthritic joints include excess production of proinflammatory cytokines (particularly IL-1β and TNF-α) and PGE 2 as well as upregulation of the expression of degradative enzymes. 6–12 Prostaglandin E 2 is a proinflammatory lipid mediator that is locally

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in American Journal of Veterinary Research

factor-α (TNF-α), which act on specific receptors within or on the surface of the targeted cells leading to inflammation. 1 Cytokines are key molecules that participate in the inflammatory response and act as mediators to facilitate the communication

Open access
in American Journal of Veterinary Research

. Although many adipokines have been discovered, extensive research has been conducted on only a handful of physiologically important compounds. Among these are leptin, TNF-α, and adiponectin. Leptin The name leptin is derived from the Greek word lept

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in Journal of the American Veterinary Medical Association