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Results for “Cartilage, Articular”

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At least 19 recordsLinked to original sources

PubMed1979

Articular cartilage preservation and storage. I. Application of tissue culture techniques to the storage of viable articular cartilage.

Articular cartilage slice explants were stored under various conditions, including freezing-thawing at various rates by using dimethyl sulfoxide (DMSO) as a cryoprotective agent, incubating in standard tissue culture medium (MEM Eagle:NCTC 135:15% fetal calf serum) in 5% CO2 and air at 4 degrees, 21 degrees, and 37 degrees C, and incubating in standard tissue culture medium containing 200 micrograms/ml alpha-tocopherol (vitamin E) at 37 degrees C after first ascertaining a dose-response curve of vitamin E. Results indicated that articular cartilage slice explants did not survive freezing or storage at 4 degrees and 21 degrees C as measured by 35S uptake. When stored at 37 degrees C in standard tissue culture in 5% CO2 and air, the slice explants remained viable for up to 60 days. The addition of alpha-tocopherol to the medium resulted in significantly less release of previously incorporated 35Sin stored cartilage slices and significantly less reduction of the amount of hexosamine present in the stored explants. alpha-Tocopherol in the medium also preserved safranin O staining. Thus, the application of tissue culture techniques to the storage of articular cartilage made it possible to preserve cartilage slice explants in a viable, biochemically "normal" state.

Animals↗

PubMed1979

Changes with age in the glycosaminoglycans of human articular cartilage.

Human articular cartilage was obtained post mortem from the lateral femoral condyles of 30 subjects aged from under 1 to 70 years. Cryostat sections taken 0--100 micrometers and 900--100 micrometers deep to the cartilage surface were exhaustively extracted to recover the glycosaminoglycans (GAG). After fractionation by cellulose acetate electrophoresis and enzyme depolymerisation individual GAG were determined by alcian blue -0.05 M MgCl2 and disaccharide microassay procedures. Changes with age were observed in GAG concentration and in the proportion of individual GAG. Large alterations occurred during the period of skeletal growth (0--16y). At birth GAG formed about 50% of the dry weight of cartilage, a value that decreased to about 15% in adult cartilage. Chondroitin sulphates (ChS) formed the principal GAG of articular cartilage and accounted for almost all of the GAG of the infant material. The ChS decreased with age and were partially replaced by keratan sulphate (KS), so the KS eventually comprised 12% of the GAG. Hyaluronic acid (HA) was identified and was found to increase linearly with age to form 6% by weight of the cartilage GAG by 60y.

Adolescent↗

PubMed2025

Localisation-Dependent Variations in Articular Cartilage ECM: Implications for Tissue Engineering and Cartilage Repair.

Articular cartilage (AC) is a specialised connective tissue covering joint surfaces. It enables smooth movement, distributes mechanical loads, and protects the underlying bone. In response to loading, AC adapts by modifying both its thickness and composition. AC is organised in different zones, with low cellularity and a high abundance of extracellular matrix (ECM). Mechanical overloading or immobilisation can lead to structural changes, potentially resulting in osteoarthritis (OA), for which no causal treatment currently exists. However, smaller defects can be treated using chondrocyte/cartilage transplantation or tissue engineering. A better understanding of the molecular composition of AC at different locations is essential to improve such therapeutic approaches. For this purpose, we performed a comprehensive analysis of porcine femoral knee cartilage at eight defined anatomical sites. Cartilage thickness and proteoglycan (PG) content were analysed histologically, while specific ECM proteins were assessed by proteomics and validated by immunohistochemistry and Western blot. Significant differences were identified, particularly between medial and lateral compartments, in terms of cartilage thickness, PG abundance, and ECM composition. Some proteins also showed zone-specific localisation patterns. These structural differences likely reflect adaptation to mechanical loading and should be considered to optimise future cartilage repair and tissue engineering strategies.

Extracellular Matrix↗

PubMed1979

Articular cartilage preservation and storage. II. Mechanical indentation testing of viable, stored articular cartilage.

Mature rabbit articular cartilage in the form of distal femoral condyles, composite osteoarticular structures, were incubated in the presence of alpha-tocopherol (200 micrograms/ml) over a period of time. Indentation testing and 35S uptake indicate preservation of sustained load carrying capacity and viability, respectively, in the presence of alpha-tocopherol for up to 30 days in organ culture. Condylar cartilage stored in the absence of alpha-tocopherol as well as frozen cartilage demonstrated progressive inability to resist sustained loading over time. Nonoptimal synthetic function apparently occurred in these latter two groups when compared to alpha-tocopherol stored material.

Animals↗

PubMed1975

Organ culture of adult human articular cartilage. II. The differential rate of glycosaminoglycan synthesis in layers of articular cartilage matrix.

Adult human articular cartilage was maintained in culture for three days and labelled with 35SO4 for the first 48 hours. The explants were sectioned horizontally on the cryostat, and the sections from the top, middle, and deep layers analyzed separately. Autoradiographs were prepared from every twentieth section. The DNA content in each of the three layers was of the same order, but the sulfate uptake and uronic acid content were considerably reduced at the surface. It is suggested that the chondrocytes synthesize matrix appropriate to the layer in which they lie.

Autoradiography↗

PubMed1977

Studies on the in vitro incubation procedure for [35S]sulphate labelling of articular cartilage glycosaminoglycans.

Articular cartilage from cow and calf femoral condyles was incubated in Tyrodes solution containing [35S]sulphate for different periods up to 80 min. Glycosaminoglycans from the cartilage tissue and incubation medium were fractionated on Cetylpyridinium chloride and ECTEOLA cellulose microcolumns. The incorporation of [35S]sulphate into all individual fractions of chondroitin sulphate and keratan sulphate was found to be linear from 20 to 80 min incubation time. As a rule the total specific activities of keratan sulphate and chondroitin sulphate were similar for both calves and cows. The proteoglycan material recovered from the medium amounted to about 1% of the tissue dry weight and was found to have a higher chondroitin sulphate: keratan sulphate ratio than the corresponding cartilage tissue for both calf and cow. The solubility profiles for the newly synthesised glycosaminoglycans, obtained from determination of the radioactivity in the individual fractions, were compared with those of glycosaminoglycans already present. These curves indicated that newly synthesised chondroitin sulphate had a higher average molecular size than that present in the tissue whereas the newly synthesised keratan sulphate had a smaller average molecular size. These newly synthesised components were also detected in the proteoglycans recovered from the incubation medium.

Animals↗

PubMed1978

Degradation of proteoglycan in articular cartilage.

Adult rabbit articular cartilage was labelled in vivo over 48 h with [35S]sulphate and was then incubated in organ culture at pH 7.2. Approx. 65% of the tissue content of [35S]proteoglycan was released into the culture medium during the first 48 h of incubation. The average molecular size of the released proteoglycans, as assessed by fractionation on Sepharose 2B/CL and 4B/Cl, was only slightly smaller than that of the proteoglycans extracted from non-cultured cartilage with 4 M guanidine HCl. The percentage of released proteoglycans and extracted proteoglycans which formed aggregates with hyaluronic acid was approx. 25% and 75%, respectively. The results indicate that proteoglycan degradation in adult articular cartilage is initiated by a limited proteolysis of subunit core protein, with the production of non-aggregating species which diffuse readily from the tissue.

Animals↗

PubMed1978

Long term effects of myochrysine in articular cartilage.

Intra-articularly administered sodium aurothiomalate (Myochrysine) produced aurosomes containing characteristic electron dense contents (indicating the presence of gold), in the chondrocytes of rabbit articular cartilage. At first the aurosomes were bounded by a membrane but later the electron dense contents were seen lying free in the cytoplasmic matrix. Such deposits were detectable up to 14 months after injection of Myochrysine but none were found at later time intervals (18 months and 2 years). There was a reduction in the population of superficial chondrocytes (Zone I) while those in deeper zones (Zones II and III) showed an increased content of intracytoplasmic filaments. It is thought that these are regressive or degenerative changes produced by gold.

Animals↗

PubMed1975

Comparison of proteoglycans from bovine articular cartilage.

Four bovine articular cartilages have been compared with regard to the chemical composition of the whole cartilages, the amount of proteoglycan selectively extracted with 3 M MGCl2 or with 3 M guanidine-HCl, and the compositions and physical properties of the isolated proteoglycans. The whole cartilages differ but slightly in composition. Occipital condylar cartilage, a thin cartilage from the smallest joint, contains 4% more collagen and proportionately less proteoglycan than proximal humeral, the thickest cartilage from the largest joint. Each cartilage contains a pool of proteoglycan that resists extraction with 3 M MgCl2 but is extracted with 3 M guanidine-HCl. The proteoglycan extracted from each cartilage with 3 M guanidine-HCl contains a high molecular weight proteoglycan-collagen complex demonstrated by analytical ultracentrifugation and by the turbidity of its visible and ultra-violet spectra. The four cartilages appear to differ most remarkably in the fraction of total proteoglycan extracted from each as proteoglycan-collagen complex.

Animals↗

PubMed1979

Lipid composition of the tissues of human knee joints. I. Observations in normal joints (articular cartilage, meniscus, ligaments, synovial fluid, synovium, intra-articular fat pad and bone marrow).

The composition and lipid profiles of the following tissues of the human knee joint were determined: articular cartilage, meniscus, ligaments, synovial fluid, synovium, intra-articular fat pad and bone marrow. The tissues were obtained from fresh cadavers and from surgical specimens. The lipid profiles of articular cartilage, meniscus and ligaments were similar to reported analyses of other tissues that are also rich in collagen. The lipid profiles for the remaining tissues were more like the profiles found in the fat depots and fatty tissues of the human body. Both the phospholipid and fatty acid patterns of these tissues were similar within statistical deviation. These results suggest that the per cent compositions of fatty acids and the phospholipid family profile ratios have limited range variability in the "normal" tissues of the human knee. On the other hand, the per cent neutral lipid compositions and their individual profiles showed great variations among the different tissue tissues of the knee.

Adipose Tissue↗

PubMed1978

The possible role of neutrophil proteinases in damage to articular cartilage.

The proteolytic degradation of articular cartilage that is seen in the arthritides affects both of the major structural components of the tissue, proteoglycan and collagen. Neutrophil leucocytes are abundant in the synovial fluid of the inflamed joints, and we have considered whether the large quantities of neutral proteinases carried by these cells could contribute to the cartilage degradation. The two neutrophil serine proteinases have been isolated, and shown to break down both proteoglycan and collagen in articular cartilage. The enzymes attacked the non-helical terminal peptides of the collagen, eliminating the cross-links, thus destabilizing and solubilizing, the fibres. The soluble collagen then denatured spontaneously, and was further degraded. Although large quantities of the neutrophil proteinases are probably released in the synovial fluid each day, the inhibitory capacity of the fluid is seldom, if ever, saturated. Nevertheless, immunologically mediated release of the neutrophil enzymes in 'frustrated endocytosis' at the cartilage surface could give rise to the generalized damage that has been reported by others.

Animals↗

PubMed1978

Subchondral route for nutrition to articular cartilage in the rabbit. Measurement of diffusion with hydrogen gas in vivo.

The route of nutrients going to articular cartilage was studied by determining the diffusion of hydrogen molecules from the subchondral circulation to the articular cartilage in rabbits. In all immature animals there was diffusion of hydrogen from subchondral bone into articular cartilage, while in the older immature animals the results were variable. None of the mature animals showed any diffusion of hydrogen into articular cartilage. The rate of diffusion of hydrogen was significantly lower in the articular cartilage than in the subchondral bone in the immature animals while the concentrations of hydrogen in the articular cartilage were only fractions of those in the subchondral bone at the same instant. Histologically, the deep layers of immature cartilage are penetrated extensively by vascular buds from the ossified portion of the epiphysis, while in adults the articular cartilage is separated from subchondral vascular spaces by an end-plate of bone. Blood vessels penetrating into the basilar layer of articular cartilage in immature animals appear to play an important role in the nutrition of articular cartilage coming from the subchondral region.

Animals↗

PubMedDate not supplied

Correlation between articular cartilage collagenase activity and osteoarthritis.

Articular cartilage collagenase activity was determined for 28 sections obtained from twelve femoral heads. For each one square centimeter area, a section was graded by a histologic-histochemical grading system for the severity of the arthritis. Collagenase activity was found primarily in those areas of moderately severe disease, but not in mild or end stage arthritis.

Aged↗

PubMed1978

Phosphorylation of proteoglycans in human articular cartilage.

A study of human articular cartilage indicated that componenet proteoglycans can be phosphorylated. Phosphorylation, also found in a specimen of human epiphysial cartilage, occurred when [gamma-32P]-ATP or 32Pi was included in the in vitro incubation medium. Treatment of the phosphorylated proteoglycans with chondroitinase and chondrosulfatases effectively removed the chondroitin sulfate without dephosphorylating the remaining molecule. Since phosphorylation could be effected in a totally chemically defined medium, it appears that the necessary enzyme systems for this reaction are contained entirely within chondrocytes.

Adult↗

PubMed1975

Electron microscopic studies of proteoglycan aggregates from bovine articular cartilage.

Proteoglycan aggregates from bovine articular cartilage have been visualized by electron microscopy of mixed proteoglycan-cytochrome c monolayers. The proteoglycan aggregates consist of proteoglycan subunits arising laterally at fairly regular intervals (20 to 30 nm) from the opposite sides of an elongated filamentous structure. The filamentous backbone in individual aggregates varies in length from 400 to 4000 nm. The individual proteoglycan subunits in the aggregate vary in length from 100 to 400 nm. However, there is no difference in the average size of the proteoglycan subunits associated with the largest or smallest aggregates. The sizes of the individual aggregates are determined mainly by the lengths of their filamentous backbones. The stoichiometry of binding of subunits to filament, calculated from the data reported here, is close to that for the binding of subunits to hyaluronic acid reported by others.

Animals↗

PubMed1979

Calcification of aging articular cartilage in man.

Calcification of the articular cartilage was studied ultrastructually using normal femoral heads obtained from necropsies of persons ranging in age from 11 months to 80 years. Mineral crystals which appeared during the initial stages of deposition were morphologically divided into two types. Type A crystals were slender, twisted and curved, measuring from 100 nm to 360 nm in length. Type B crystals were short, needle-like and slightly curved, measuring from 30 nm to 160 nm in length. Type A crystals were found mainly in the developing epiphysis during childhood. Type B crystals were generally found in the calcified zone of adult articular cartilage. Both types of crystals initially appeared in close proximity to extracellular membrane-invested electron dense particle called "matrix vesicles", and gradually increased in number to form calcified cartilage matrix. The morphological differences between type A and B crystals might be caused by biochemical alterations of the cartilage matrices and/or biomechanical changes in the joints of children and adults.

Adolescent↗

PubMed1979

Effect of salicylate on proteoglycan metabolism in normal canine articular cartilage in vitro.

In osteoarthritis, diminished aggregation of articular cartilage proteoglycans affects tissue biomechanics. Since salicylates are commonly employed in treatment of osteoarthritis, we examined the effect of sodium salicylate on proteoglycan metabolism and aggregation in normal canine articular cartilage. At salicylate concentrations of 10(-3)M, 5 X 10(-3)M and 10(-2)M, net proteoglycan synthesis in normal canine articular cartilage was 73%, 42% and 16% respectively, of control levels. Catabolism of glycosaminoglycans in the presence of 10(-3)M salicylate (which corresponds to a serum salicylate level of 20-25 mg %) was the same as that in control cartilage, while higher concentrations of the drug increased the rate of degradation. The hydrodynamic size of newly synthesized proteoglycan aggregates and of disaggregated proteoglycans was unaffected by sodium salicylate.

Animals↗

PubMed1979

Reconstruction of articular cartilage with free autologous perichondrial grafts. An experimental study in rabbits.

An experimental study in adult rabbits has been performed to find out whether the cartilage forming capacity of the perichondrium could be utilized in reconstruction of articular cartilage. The normal articular cartilage of the glenoid surface of the humero-scapular joint was completely removed. Auricular perichondrium was grafted to cover the exposed bony surface with the active chondrogenic layer of the perichondrial graft facing the joint cavity. The joint was not immobilized but the operated limb was amputated at wrist level to avoid weight bearing. The animals were sacrificed at different time intervals ranging from 1 to 17 weeks. In 12 out of 14 grafted rabbits regeneration of cartilage occurred. In 6 of 10 control cases where no perichondrium was grafted to cover the resected surface no cartilage was found. In the other 4, only small areas of mature cartilage were seen, probably remnants of the original articular cartilage.

Amputation, Surgical↗