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PubMed1985

Studies into the influence of carrageenan-induced inflammation on articular cartilage degradation using implantation into air pouches.

We describe a novel system for examining the degradation of articular cartilage in vivo. Implantation of rat femoral head cartilage into six day old subcutaneous air pouches allows the examination of the degradation of cartilage in contact with a synovial lining-like structure. Femoral head cartilage was removed 1, 2 or 3 weeks after implantation and the proteoglycan content measured using 1,9-dimethyl methylene blue. Chondrocyte viability was confirmed using 35S sulphate incorporation. Increasing proteoglycan loss was observed over 3 weeks. Loss was similar in transplants between inbred and between outbred animals, suggesting that allograft rejection did not contribute significantly. Introduction of the irritant carrageenan into pouches produced a massive and prolonged inflammatory response characterized by exudation of leucocyte-rich fluid. Induction of inflammation with carrageenan did not alter the profile of proteoglycan loss from whole, minced, live or dead cartilage, as compared to that seen in non-inflamed pouches. These results indicate that when the relationship between articular cartilage and its normal tissue surroundings is disturbed, rapid proteoglycan loss may occur. The conditions induced by carrageenan inflammation have, in comparison, little or no effect on cartilage degradation. This raises the possibility that the direct effects of inflammatory products are of relatively minor importance to cartilage destruction in human arthritis.

Animals↗
PubMed1993

N.m.r. spectroscopic studies of fucose-containing oligosaccharides derived from keratanase digestion of articular cartilage keratan sulphates. Influence of fucose residues on keratanase cleavage.

Keratan sulphate chains from bovine articular cartilage were fully digested with keratanase from Pseudomonas sp. and the products were reduced with alkaline borohydride. The resultant fragments were fractionated on a Nucleosil 5SB column and the earliest eluting fucose-containing oligosaccharides were isolated. Structural analysis using 1H n.m.r. spectroscopy (600 MHz) showed the two least-charged species to have the following structure: GlcNAc(6S) beta 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc(6S) beta 1- 3Gal beta 1-4GlcNAc(6S) beta 1-3Gal-ol and GlcNAc(6S) beta 1-3Gal beta 1- 4(Fuc alpha 1-3)GlcNAc(6S) beta 1-3Gal beta 1-4GlcNAc(6S) beta 1-6(Gal beta 1- 3)GalNAc-ol. Both galactoses adjacent to the fucosylated N-acetylglucosamine residue are unsulphated. Therefore, it can be deduced from these structures that the presence of fucose on N-acetylglucosamine residues in keratan sulphates protects both of the adjacent unsulphated galactose residues from keratanase cleavage. This result has implications for the interpretation of keratanase fingerprints, because in articular cartilage keratan sulphates the keratanase-resistant blocks are not solely those with fully sulphated galactose residues, but also include the fucosylated sequences, which have unsulphated galactoses. It is, therefore, not possible to estimate their galactose sulphation or the size of the fully sulphated disaccharide-repeat sequences from keratan sulphates that contain fucose.

Acetylglucosamine↗
PubMed1998

Expression of type X collagen and matrix calcification in three-dimensional cultures of immortalized temperature-sensitive chondrocytes derived from adult human articular cartilage.

Chondrocytes isolated from normal adult human articular cartilage were infected with a retroviral vector encoding a temperature-sensitive mutant of the simian virus 40 large tumor antigen and a linked geneticin (G418)-resistance marker. G418-resistant colonies were then isolated, ring-cloned, and expanded in serum-containing media. Several immortalized chondrocyte cell lines were established from the clones that survived, some of which have been maintained in continuous culture for over 2 years. Despite serial subcultures and maintenance as monolayers, these cells retain expression of markers specific for cells of the lineage, namely type II collagen and aggrecan, detected immunocytochemically. We also examined the phenotype of three of these immortalized cell lines (designated HAC [human articular chondrocyte]) using a pellet culture system, and in this report, we present evidence that a prototype of these lines (HAC-F cells) expresses markers normally associated with hypertrophic chondrocytes. When HAC-F cells were cultivated in centrifuge tubes, for periods of up to 63 days, at 39 degrees C with mild and intermittent centrifugation they continued to express both lineage markers; total type II collagen/pellet remained stable, whereas there was a temporal decrease in cartilage-specific glycosaminoglycans content. In addition, in the presence of ascorbate but in the absence of a phosphate donor or inorganic phosphate supplement, the cells also begin to express a hypertrophic phenotype characterized by type X collagen synthesis and extensive mineralization of the extracellular matrix in late stage cultures. The mRNA encoding type X collagen was detected in the cell pellets by reverse transcriptase polymerase chain reaction as early as day 2, and anti-type X collagen immunoreactivity was subsequently localized in the matrix. The mineral was characterized by energy-dispersive X-ray microanalysis as containing calcium (Ca) and phosphorus (P) with a Ca:P peak height ratio close to that of mineralized bone tissue. The unexpected phenotype of this human chondrocyte cell line provides an interesting opportunity for studying chondrocyte maturation in vitro.

Adult↗
PubMed1993

Adaptation of canine femoral head articular cartilage to long distance running exercise in young beagles.

OBJECTIVE: To study the effects of long term (one year), long distance (up to 40 km/day) running on the metabolism of articular cartilage the biosynthesis of proteoglycans was examined by in vitro labelling of anterior (weight bearing) and posterior (less weight bearing) areas of the femoral head from young beagles. METHODS: Total sulphate incorporation rates were determined and distribution of the incorporated sulphate was localised by quantitative autoradiography. Concentration and extractability of the proteoglycans were determined, and proteoglycan structures were investigated by gel filtration chromatography, agarose gel electrophoresis, and chemical determinations. RESULTS: In the less weight bearing area the amount of extractable proteoglycans was decreased (p < or = 0.02), simultaneously with an increased concentration of residual glycosaminoglycans in the tissue after 4 M GuCl extraction (p < or = 0.05). In control animals proteoglycan synthesis was most active in the deep zone of the cartilage, whereas exercise increased synthesis in the intermediate zone. There was a tendency to a lower keratan: chondroitin sulphate ratio in the running dogs. No macroscopical or microscopical signs of articular degeneration or injury were visible in any of the animals. CONCLUSION: The articular cartilage of the femoral head showed a great capacity to adapt to the increased mechanical loading. The reduced proteoglycan extractability in the less weight bearing area changed it similar to the weight bearing area, suggesting that the low extractability of proteoglycans reflects the long term loading history of articular cartilage. The congruency of the femoral head with acetabulum seems to protect the cartilage from the untoward alterations that occur in the femoral condyles subjected to a similar running programme.

Adaptation, Physiological↗
PubMed2003

Poly(hydroxybutyrate-co-hydroxyhexanoate) promoted production of extracellular matrix of articular cartilage chondrocytes in vitro.

The present investigation describes the production of extracellular matrix of rabbit articular cartilage chondrocytes grown on scaffolds of polyhydroxybutyrate (PHB) blended with poly(hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) for up to 7 days. The mRNA level of type II collagen of chondrocytes seeded on all scaffolds consisting of PHBHHx were obviously higher than that of PHB-only scaffold throughout the culture period, suggesting the positive effect of PHBHHx on extracellular matrix production. Second-harmonic generation (SHG) imaging technique, combined with confocal fluorescence microscopy (CFM) revealed that PHBHHx in PHB scaffold provided better surface properties for anchoring type II collagen filaments and their penetration into internal layers of the scaffolds. Glycosaminoglycan (GAG), a major composition of extracellular matrix, showed a sharp increase in construct of 1:2 PHB/PHBHHx scaffold after 7 day cultivation, while only a small increase was observed in all other tested scaffolds. At the same time, total collagen contents in all scaffolds containing PHBHHx increased with time, with the maximum collagen production of 742.1+/-99.2mg/g dry weight observed in construct of 1:2 PHB/PHBHHx scaffold inoculated for 7 days, this was almost 4-fold higher than that in scaffold of PHB only. It appears that the presence of right proportion of PHBHHx in the composite system of PHB/PHBHHx highly favored the production of extracellular matrix of articular cartilage chondrocytes.

3-Hydroxybutyric Acid↗
PubMed1996

Collagen type X: a component of the surface of normal human, pig, and rat articular cartilage.

Collagen type X, a protein generally associated with hypertrophic chondrocytes of avian and mammalian growth plate during endochondral growth of long bones, has been previously shown to be present during disruption of normal metabolic status of articular cartilage during osteoarthritis. We have demonstrated that collagen type X is present as a component of normal articular cartilage in adult human, growing pig and new-born rat. The protein was immunolocalized in these tissues at the surface of the articular cartilage and for human tissue there was some staining of chondrocytes adjacent to the "tidemark' zone. The presence of collagen type X was confirmed by isolating the protein from these tissues and its identification by SDS-PAGE and immunodetection with antibodies specific for collagen type X.

Adult↗
PubMed1994

[Immunohistochemical localization of transforming growth factor-beta 1 in growth plate freshly transplanted into a full-thickness defect in articular cartilage].

Transplants of the epiphyseal growth plate obtained from the proximal tibia of Lewis rats at 3 weeks of age were inserted into full-thickness defects in the patellofemoral articular surface of Lewis rats at 5 weeks of age. As controls, similar surface defects were induced but no transplants were inserted. Transplants were studied immunohistochemically at varying intervals up to 72 weeks in order to determine the effects of transforming growth factor-beta 1 (TGF-beta 1) on the repair of the articular cartilage by the epiphyseal growth plate. TGF-beta 1 was present in chondrocytes in the region corresponding to the hypertrophic zone of the transplanted growth plate at 1 week after transplantation. The distribution pattern of TGF-beta 1 in this hypertrophic zone was similar to that prior to transplantation. At 2 weeks after transplantation, TGF-beta 1 was detected in the matrix, but the hypertrophic chondrocyte cell membranes were not clear. TGF-beta 1 was undetectable in the transplanted growth plate at 4 weeks after transplantation, at which time a morphological examination revealed metaplastically-transformed articular cartilage but no hypertrophic cartilage cells. No immunostaining of TGF-beta 1 was present in the untreated articular defect. These findings suggested that TGF-beta 1 in the hypertrophic chondrocytes was probably transferred from the cytoplasm to the extracellular matrix and stimulated the ossification of the matrix with vessel induction and osteoid formation during the process of incorporation of the transplant into the articular cartilage defect.

Animals↗
PubMed2002

Extra-articular cartilage affected in collagen-induced, but not pristane-induced, arthritis models.

Rheumatoid arthritis (RA) is a chronic inflammatory disease primarily affecting cartilaginous joints but also extra-articular tissues such as the nose and upper respiratory tract. We have investigated extra-articular cartilage involvement in two commonly used animal models for RA, collagen-induced and pristane-induced arthritis, by immunizing rats with different susceptibility to disease (LEW.1 A, LEW.1F and DA rats). We found that nasal and tracheolaryngeal cartilage is affected in LEW.1 A and DA rats to varying degrees in collagen-induced arthritis but not in any strain in the pristane-induced model. Antibodies to matrilin-1, a cartilage-specific protein expressed mainly in tracheolaryngeal and nasal cartilage but not in joints, were positively associated with the presence of inflammation in nasal cartilage. In contrast, no antibody response to matrilin-1 could be detected in pristane-induced arthritis. In addition, nasal vaccination with collagen type II prior to immunization in DA rats significantly decreased the antibody response to matrilin-1 at day 56, but not at earlier time points, indicating a late protective effect on extra-articular cartilage. We conclude that pristane-induced arthritis is a joint-specific model whereas collagen-induced arthritis affect joints as well as extra-articular cartilage. Furthermore, collagen immunization induces an antibody response to matrilin-1.

Animals↗
PubMed1983

Relationship between matrix proteoglycan content and the effects of salicylate and indomethacin on articular cartilage.

When 160 microgram/ml sodium salicylate was added to the culture medium, glycosaminoglycan synthesis in slices of normal articular cartilage from habitually loaded areas of canine femoral condyles was diminished by 24% (P less than 0.01). Although glycosaminoglycan synthesis in cartilage from habitually unloaded regions of the same joints was similar to that in cartilage from loaded sites, the mean uronic acid content of the former was about 25% less, and salicylate suppressed glycosaminoglycan synthesis in unloaded cartilage to a much greater extent (42% of control) than it did in loaded cartilage (P less than 0.01). Furthermore, 1.5 micrograms/ml indomethacin, which had no effect on cartilage from loaded regions, suppressed glycosaminoglycan synthesis in cartilage from unloaded regions by 31%. However, if cartilage from loaded regions was treated with testicular hyaluronidase, indomethacin inhibited glycosaminoglycan synthesis, and inhibition of glycosaminoglycan metabolism by salicylate in hyaluronidase-treated cartilage was greater than in untreated cartilage. The data suggest that the effects of nonsteroidal antiinflammatory drugs on glycosaminoglycan metabolism in articular cartilage are dependent on proteoglycan content of the extracellular matrix.

Animals↗
PubMed1997

Chondrocyte transplantation to articular cartilage explants in vitro.

The transplantation of chondrocytes has shown promise for augmenting the repair of defects in articular cartilage. This in vitro study examined the efficiency of the transplantation of bovine chondrocytes onto articular cartilage disks and the ability of the transplanted chondrocytes to subsequently synthesize and deposit proteoglycan. The radiolabeling of chondrocyte cultures with [3H]thymidine, followed by 4 days of chase incubation, resulted in the incorporation of 98% of the radiolabel into DNA (as assessed by susceptibility to DNase). At the end of the culture period, the [3H]DNA was stable, with a half-life of radioactivity loss into the medium of 73 days. With use of radiolabeled chondrocytes for quantitation, the efficiency of transplantation onto a cartilage substrate was 93 +/- 4% for seeding densities of as much as 650,000 cells per cm2 and a seeding duration of 1 hour. These findings were confirmed both by tracking cells stained with 5-chlormethylfluorescein diacetate and by quantitating DNA. During the 16 hours after seeding onto a cartilage substrate (in which the endogenous cells had been lysed by lyophilization), the transplanted cells synthesized sulfated proteoglycan in direct proportion to the number of cells seeded. Most (83%) of the newly synthesized proteoglycan was released into the medium rather than retained within the layer of transplanted cells and the recipient cartilage substrate. Comparative studies with lyophilized-rehydrated or live cartilage as the recipient substrate indicated a similar efficiency of chondrocyte seeding and proteoglycan synthesis by the seeded chondrocytes. The transplanted cells retained the chondrocyte phenotype, as judged by a high proportion of the [35S]macromolecules being in the form of aggrecan that was capable of aggregating with hyaluronan and link protein, as well as by immunostaining within and around the transplanted cells for type-II, but not type-I, collagen. These results indicate that the number of chondrocytes transplanted onto a cut cartilage surface greatly affects the level of matrix synthesis; this in turn may affect repair.

Animals↗
PubMed1995

Use of a guanidine extract of demineralized bone in the treatment of osteochondral defects of articular cartilage.

In order to evaluate the ability of a guanidine extract of demineralized bone to repair osteochondral defects in articular cartilage, plugs made of this extract were implanted into defects in rabbit knees. The repair tissue was examined macroscopically, histologically, and immunohistochemically at 4, 8, 12, and 30 weeks. Controls (defects that were left empty) showed no cartilage formation. Four weeks after implantation of a guanidine extract plug, histological examination showed a nonhomogeneous metachromatically stained region extending from the surface of the repair tissue down to cancellous bone. This region also was labeled by an anti-type-II collagen antibody, indicating that cartilage-like tissue had been induced. At 8 weeks, the newly formed cartilage in the subchondral and cancellous bone had been partially replaced by bone. At 12 weeks, the thickness of the newly formed cartilage layer had decreased, and most of the newly formed cartilage in the subchondral and cancellous bone had been replaced by bone. In addition, a tidemark was observed. At 30 weeks, the repair tissue was a mixture of cartilage and fibrocartilage, and there was severe degeneration of the cartilage surrounding the repaired defects. These findings indicate that osteochondral defects of articular cartilage can be partially repaired by the implantation of a guanidine extract and that the newly formed cartilage-like tissue is not permanent.

Animals↗
PubMed1951

Radioautographic visualization of sulfur-35 disposition in the articular cartilage and bone of suckling rats following injection of labeled sodium sulfate.

The localization of sulfur-35 administered intraperitoneally as sodium sulfate to 7-day-old rats was determined by radioautography of sections of humeri and tibia-knee-femur combinations removed 24, 48, 96, 216, and 290 hours after injection of this isotope. Radioautography of sections of bone and cartilage that had been fixed in formalin indicated that the tracer isotope was present throughout the entire epiphysis. Its concentration therein was highest initially at the epiphyseal-diaphyseal junction where the more mature cartilage cells were present. By the 96th hour post injection the sulfur-35 had become more uniformly distributed in the epiphyses and an even distribution of it throughout the epiphyseal cartilage was almost attained by the 216th hour post injection. As centers of secondary ossification arose in the epiphyseal cartilage, the sulfur-35 appeared to diminish in concentration and disappear from these loci. However, radioautographs of cartilage fixed in formalin saturated with barium hydroxide, instead of in formalin only, disclosed the fact that the tracer isotope was still present in these loci. When bone and bone marrow were fixed in formalin the autographs indicated the presence of sulfur-35 primarily in the periosteum. Only a negligible amount appeared to be present in the bone shaft and marrow. However, when these tissues were fixed in formalin saturated with barium hydroxide it was possible to demonstrate the presence of the tracer isotope in both bone and bone marrow.

Animals↗
PubMed2006

Proteoglycan synthesis in bovine articular cartilage explants exposed to different low-frequency low-energy pulsed electromagnetic fields.

OBJECTIVE: To investigate the role of pulsed electromagnetic field (PEMF) exposure parameters (exposure length, magnetic field peak amplitude, pulse frequency) in the regulation of proteoglycan (PG) synthesis of bovine articular cartilage explants. METHODS: Bovine articular cartilage explants were exposed to a PEMF (75 Hz; 2 mT) for different time periods: 1, 4, 9, 24 h. Then, cartilage explants were exposed for 24 h to PEMFs of different magnetic field peak amplitudes (0.5, 1, 1.5, 2 mT) and different frequencies (2, 37, 75, 110 Hz). PG synthesis of control and exposed explants was determined by Na2-35SO4 incorporation. RESULTS: PEMF exposure significantly increased PG synthesis ranging from 12% at 4 h to 17% at 24 h of exposure. At all the magnetic field peak amplitude values, a significant PG synthesis increase was measured in PEMF-exposed explants compared to controls, with maximal effect at 1.5 mT. No effect of pulse frequency was observed on PG synthesis stimulation. CONCLUSIONS: The results of this study show the range of exposure length, PEMF amplitude, pulse frequency which can stimulate cartilage PG synthesis, and suggest optimal exposure parameters which may be useful for cartilage repair in in vivo experiments and clinical application.

Animals↗