Loading-induced changes in synovial fluid affect cartilage metabolism (original) (raw)
Related papers
Cartilage extracellular matrix metabolism differs in serum and synovial fluid
Methods in cell science : an official journal of the Society for In Vitro Biology, 2002
Most cartilage explant culture studies assume conventional serum-supplemented growth media are biologically equivalent to the natural synovial fluid which baths cartilage in vivo. Few studies have systematically compared the effects of serum versus synovial fluid in culture. To address this assumption we conducted a series of studies to determine if cartilage matrix synthesis is significantly different in serum-based versus synovial fluid-based media. Normal bovine cartilage explants were cultured in DMEM either alone or supplemented with bovine serum or bovine synovial fluid. Matrix synthesis was measured with radiolabeling techniques. We then compared responses to insulin-like growth factor I (IGF-I, a stimulator of matrix synthesis), and interleukin-1beta (IL-1beta, an inhibitor of matrix synthesis). We observed significantly lower matrix synthesis activity in synovial fluid versus serum. Caution shoud be used in extrapolating studies of cartilage grown in media supplemented with...
Osteoarthritis and Cartilage, 1997
Articular cartilage degeneration in the middle carpal joint is a common problem in racing horses. This study evaluated the effect of exercise on the in-vitro synthesis of the large aggregating proteoglycans (aggrecan) and two small proteoglycans, biglycan and decorin, in articular cartilage taken from three weight bearing regions of the third carpal bone of horses which were subjected to moderate or strenuous exercise. Twelve Standardbred horses free from clinical and radiographic disease of the middle carpal joint were subjected to an 8 week moderate exercise program. The horses were then randomly assigned to two groups: group ~c o n t i n u e d moderate exercise and group B-strenuous exercise for 17 weeks. Horses were then rested for 16 weeks. Full-depth articular cartilage explants from the dorsal radial facet (DRF), dorsal intermediate facet (DIF) and palmar condyle (PC) of the third carpal bone were collected and cultured. Cartilage proteoglycan content and release into culture media were measured. Newly synthesized proteoglycans were labeled with a~SO42-for 48 h and analyzed by size exclusion and hydrophobic chromatography, sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis (PAGE) and autoradiography. Histologic sections of adjacent osteochondral regions were evaluated for evidence of arthritic change. No histologic abnormalities or differences in proteoglycan content were detected in any of the articular cartilage regions examined. There was however, a significant reduction (P < 0.05) in aggrecan synthesis and a concomitant increase in decorin synthesis (P < 0.05) in articular cartilage from the DRF of group B animals. There was no change in biglycan synthesis, aggrecan hydrodynamic size or ability to aggregate in any articular cartilage region. This study has demonstrated that strenuous exercise in horses can lead to a disturbance in the biosynthesis of proteoglycans in articular cartilage regions subjected to high contact stresses (DRF). These metabolic abnormalities, which persisted for 16 weeks after cessation of exercise, could have deleterious effects on the biomechanical properties of the tissue. We suggest that the observed alteration in articular cartilage metabolism in CRF cartilage of strenuously exercised horses could represent a predisposing factor for cartilage degeneration and osteoarthritis at a later stage.
The Proteoglycan Metabolism of Articular Cartilage in Joint-Scale Culture
Tissue Engineering Part A, 2010
Understanding and controlling chondrocyte and cartilage metabolism in osteochondral tissues may facilitate ex vivo maintenance and application, both for allografts and tissue-engineered grafts. The hypothesis of this study was that maintenance of chondrocyte viability and matrix content and release of sulfated glycosaminoglycan (sGAG) in the articular cartilage of joint-scale osteochondral fragments are temperature and metabolism dependent. The aims were to assess, for adult goat joints, the effects of incubation temperature (378C vs. 48C) on cartilage chondrocyte viability and tissue matrix content and mechanical function, and the effects of temperature and cellular biosynthesis on sGAG release. Chondrocyte viability was maintained with 378C incubation for 28 days, but decreased by *30% with 48C incubation. Concomitantly, with 378C incubation, cartilage sGAG was depleted by *52% with the lost sGAG predominantly unable to aggregate with hyaluronan, whereas collagen content, tissue thickness, and tissue stiffness were maintained. The depletion of sGAG was diminished by slowing metabolism, with 48C decreasing release by *79% compared with 378C incubation, and cycloheximide inhibition of cell metabolism at 378C decreasing release by *47%. These results indicate that the articular cartilage of joint-scale grafts have enhanced chondrocyte viability with incubation at 378C, but may need anabolic stimuli or catabolic inhibitors to maintain sGAG content.
Clinical Orthopaedics and Related Research, 1992
The recovery of articular cartilage from atrophy induced by joint immobilization was investigated in immature dogs. In a previous study, we showed that 11 weeks of immobilization of the knee (stifle) joint of young dogs reduced the concentration of articular cartilage glycosaminoglycans (GAGs) by 13-47%. In the present study, right hindlimbs from six female beagles were immobilized for 11 weeks, as in the previous study, and then were remobilized for 15 weeks. Cartilage from the knee joint was compared with cartilage from nonimmobilized knees of eight age-matched control beagles. Histological samples taken from 11 different locations of the knee joint were stained with safranin 0, and microspectrophotometry was used to demonstrate distribution of GAGs in the tissue. After remobilization, GAG concentration was restored in the patellofemoral region and tibia1 condyles. On the summits of the femoral condyles, and especially at the periphery of the femoral condyles, GAG concentration remained 8-26% less than the control values. On the summits, the thickness of the uncalcified cartilage was as much as 15% less than in the age-matched controls. Consequently, the changes induced by unloading were reversible to a great extent, but a full restoration of articular cartilage was not obtained at all sites of the knee joint within the 15 weeks of remobilization. Immobilization of the skeletally immature joint therefore may affect the development of articular cartilage in such a way that very slow recovery or permanent alterations are induced.
Metabolic responses of cartilage in experimentally induced osteoarthritis
Annals of the Rheumatic Diseases, 1981
Serial metabolic responses in developing osteoarthritis induced in the right knees of a rabbit model of partial meniscectomy (PM) were studied. Controls were sham-operated (SH) right knees, left knees of all operated animals, and right and left knees of a nonoperated series. Glycosaminoglycan and protein synthesis and cell replication were separately analysed utilising 35SO4,
Osteoarthritis and Cartilage, 1996
The effects of inflammation on the biochemical and biomechanical properties of articular cartilage at two sites (dorsal and palmar) from the radial facet of the equine third carpal bone were examined in response to a synovitis induced with Escherichia coli lipopolysaccharide (LPS). Four groups were studied. In group 1 synovitis was induced at time zero and evaluated at week 6. Group 2 was the sham-treated control for group 1. In group 3 synovitis was induced at time zero and evaluated at week 2. Group 4 was the sham-treated control for group 3. There was a significant increase (P < 0.05) in newly synthesized proteoglycan PG from both sites in group 3 as compared to the sham-treated groups and group 1. No significant difference in the endogenous PG concentration between groups or sites was detected. Sepharose CL-2B revealed two peaks of newly synthesized PG in all groups; an early peak (Kay 0.11-0.13) and a late peak (Kay 0.48-0.64). Newly synthesized PG profiles from sham-treated groups and group 3 were similar, but the group 3 PG profile exhibited a more pronounced early peak. Conversely, the PG profile from group 1 demonstrated a more prominent late peak. Electrophoresis and Western blot analysis of the pooled late PG peak fractions from the sham-treated and group 1 showed a single toluidine blue stained band from both sites which reacted with monoclonal antibody (MAb) 1C6. By contrast, the late peak from the palmar site in group 3 showed an additional faster moving component .on composite gels which did not react with MAb 1C6. There was a significant decrease in Poisson's ratio and a significant increase in cartilage thickness in groups 1 and 3 which had received synovitis. The increase in cartilage thickness of groups 1 and 3 was also significantly affected by site (dorsal > palmar). There was no significant difference in aggregate modulus or permeability constant among groups. Primary joint inflammation induced by LPS alters the biochemical and biomechanical properties of the articular cartilage as a function of time and site. An increase in chondrocyte PG synthesis in the early period following synovitis may be a reparative response to the inflammatory insult. Continued alterations in the qualitative PG composition in the later period following synovitis may represent a shift in chondrocyte metabolism to repopulate the existing cartilage matrix.
Anabolic and catabolic responses of human articular chondrocytes to varying oxygen percentages
Arthritis Research & Therapy, 2010
Introduction: Oxygen is a critical parameter proposed to modulate the functions of chondrocytes ex-vivo as well as in damaged joints. This article investigates the effect of low (more physiological) oxygen percentage on the biosynthetic and catabolic activity of human articular chondrocytes (HAC) at different phases of in vitro culture. Methods: HAC expanded in monolayer were cultured in pellets for two weeks (Phase I) or up to an additional two weeks (Phase II). In each Phase, cells were exposed to 19% or 5% oxygen. Resulting tissues and culture media were assessed to determine amounts of produced/released proteoglycans and collagens, metalloproteinases (MMPs), collagen degradation products and collagen fibril organization using biochemical, (immuno)-histochemical, gene expression and scanning electron microscopy analyses. In specific experiments, the hypoxia-inducible factor-1α (HIF-1α) inhibitor cadmium chloride was supplemented in the culture medium to assess the involvement of this pathway. Results: Independent from the oxygen percentage during expansion, HAC cultured at 5% O 2 (vs 19% O 2 ) during Phase I accumulated higher amounts of glycosaminoglycans and type II collagen and expressed reduced levels of MMP-1 and MMP-13 mRNA and protein. Switching to 19% oxygen during Phase II resulted in reduced synthesis of proteoglycan and collagen, increased release of MMPs, accumulation of type II collagen fragments and higher branching of collagen fibrils. In contrast, reducing O 2 during Phase II resulted in increased proteoglycan and type II collagen synthesis and reduced expression and release of MMP-13 mRNA and protein. Supplementation of cadmium chloride during differentiation culture at 5% O 2 drastically reduced the up-regulation of type II collagen and the down-regulation of MMP-1 mRNA. Conclusions: The application of more physiologic oxygen percentage during specific phases of differentiation culture enhanced the biosynthetic activity and reduced the activity of catabolic enzymes implicated in cartilage breakdown. Modulation of the oxygen percentage during HAC culture may be used to study pathophysiological events occurring in osteoarthritis and to enhance properties of in vitro engineered cartilaginous tissues.