Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CARTILAGE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 433 records · Page 24Linked to original sources
PubMed1990

Acidic fibroblast growth factor (aFGF) injection stimulates cartilage enlargement and inhibits cartilage gene expression in rat fracture healing.

The effect of the administration of acidic fibroblast growth factor (aFGF) on normal fracture healing was examined in a rat fracture model. One microgram of aFGF was injected into the fracture site between the first and the ninth day after fracture either every other day or every day. aFGF-injected calluses were significantly larger than control calluses, although this does not imply an increased mechanical strength of the callus. Histology showed a marked increase in the size of the cartilaginous soft callus. Total DNA and collagen content in the cartilaginous portion of the aFGF-injected calluses were greater than those of controls, although the collagen content/DNA content ratio was not different between the aFGF-injected and control calluses. Fracture calluses injected with aFGF remained larger than controls until 4 weeks after fracture. The enlarged cartilaginous portion of the aFGF-injected calluses seen at 10 days after fracture was replaced by trabecular bone at 3 and 4 weeks. Northern blot analysis of total cellular RNA extracted separately from the cartilaginous soft callus and the bony hard callus showed decreased expression of type II procollagen and proteoglycan core protein mRNA in the aFGF-injected calluses when compared with controls. A slight decrease in types I and III procollagen mRNA expression was also observed. We concluded that aFGF injections induced cartilage enlargement and decreased mRNA expression for type II procollagen and proteoglycan core protein.

Animals↗
PubMed1995

Progression and recapitulation of the chondrocyte differentiation program: cartilage matrix protein is a marker for cartilage maturation.

During endochondral bone formation, chondrocytes in the cartilaginous anlage of long bones progress through a spatially and temporally regulated differentiation program before being replaced by bone. To understand this process, we have characterized the differentiation program and analyzed the relationship between chondrocytes and their extracellular environment in the regulation of the program. Our results indicate that, within an epiphyseal growth plate, the zone of proliferating chondrocytes is not contiguous with the zone of hypertrophic chondrocytes identified by the transcription of the type X collagen gene. We find that the postproliferative chondrocytes which make up the zone between the zones of proliferation and hypertrophy specifically transcribe the gene for cartilage matrix protein (CMP). This zone has been termed the zone of maturation. The identification of this unique population of chondrocytes demonstrates that the chondrocyte differentiation program consists of at least three stages. CMP translation products are present in the matrix surrounding the nonproliferative chondrocytes of both the zones of maturation and hypertrophy. Thus, CMP is a marker for postmitotic chondrocytes. As a result of the changes in gene expression during the differentiation program, chondrocytes in each zone reside in an extracellular matrix with a unique macromolecular composition. Chondrocytes in primary cell culture can proceed through the same differentiation program as they do in the cartilaginous rudiments. In culture, a wave of differentiation begins in the center of a colony and spreads to its periphery. The cessation of proliferation coincides with the appearance of CMP and eventually the cells undergo hypertrophy and synthesize type X collagen. These results reveal distinct switches at the proliferative-maturation transition and at the maturation-hypertrophy transition during chondrocyte differentiation and indicate that chondrocytes synthesize new matrix molecules and thus modify their preexisting microenvironment as differentiation progresses. However, when "terminally" differentiated hypertrophic chondrocytes are released from their surrounding environment and incubated in pellet culture, they stop type X collagen synthesis, resume proliferation, and reinitiate aggrecan synthesis. Eventually they cease proliferation and reinitiate CMP synthesis and finally type X collagen. Thus they are capable of recapitulating all three stages of the differentiation program in vitro. The data suggest a high degree of plasticity in the chondrocyte differentiation program and demonstrate that the progression and maintenance of this program is regulated, at least in part, by the extracellular environment which surrounds a differentiating chondrocyte during endochondral bone formation.

Aggrecans↗
PubMed2004

Proteoglycans in human laryngeal cartilage. Identification of proteoglycan types in successive cartilage extracts with particular reference to aggregating proteoglycans.

The content, composition and structure of proteoglycans (PGs) in adult human laryngeal cartilage (HLC) were investigated. PGs were extracted from the tissue by using two different extraction protocols. In the first protocol, PGs were extracted under dissociative conditions, 4 M guanidine HCl (GdnHCl), and in the second protocol, sequentially, with phosphate buffered saline (PBS) and solutions of increasing GdnHCl concentration (0.5, 1, 2 and 4 M). Chemical and immunological analyses of dissociate extracts (first protocol) revealed the presence of four, at least, different types of PGs. Aggrecan was the major PG, versican, decorin and biglycan being in small amounts. Galactosaminoglycan-containing PGs (GalAGPGs) represented the vast majority of total PGs present in extracts of HLC. Differential digestion with chondroitinase ABC and AC II showed that the GalAGPGs from HLC contained a significant proportion of dermatan sulphate (DS). In addition, disaccharide analysis showed that 6-sulphated disaccharides predominated in chondroitin sulphate (CS) chains. The sequential extraction (second protocol) indicated that PBS extract contained very little amount of PGs. The 0.5, 1 and 2 M GdnHCl extracts contained 6.3%, 24.5% and 15.2% of total extracted PGs, respectively. Four molar GdnHCl extracted the larger proportion, about 53%, of total PGs. This extract contained almost only proteoglycan aggregate components i.e., G1 bearing aggrecan, hyaluronan and link protein. The characterization of the aggrecan showed that it constituted a polydisperse population of monomers with an average molecular mass of 720 kDa. The glycosaminoglycans (GAGs) present were chondroitin sulphate with a M(r) of 15 kDa, and keratan sulphate (KS) with a M(r) of 10 kDa, in proportions 84% and 16%, respectively.

Adult↗
PubMed1981

A comparative study of the binding of cartilage link protein and the hyaluronate-binding region of the cartilage proteoglycan to hyaluronate-substituted Sepharose gel.

The hyaluronate-binding proteins from bovine nasal cartilage, i.e. the hyaluronate-binding region of the proteoglycan and the link protein, were labelled with 125I and separated from each other by gel chromatography. The proteins were characterized by molecular-weight determinations and their purity was established by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and immunodiffusion. The binding properties of the two proteins by hyaluronate-substituted Sepharose gel were compared. It was found that both proteins behaved similarly. They bound with the same efficiency to the gel, they showed the same time course of binding, had slightly different pH optima for binding and both proteins had a decreasing affinity for the gel with increasing ionic strength. The binding to the gel could be inhibited by soluble hyaluronate, and the minimum size of a hyaluronate oligosaccharide required for inhibition was in both cases a decasaccharide (only even-numbered oligosaccharides were tested). The proteins did not show any co-operative binding in the system tested, which could be explained by the large number of binding sites in the hyaluronate-substituted gel. Binding constants for the protein-hyaluronate interaction were estimated. A value of 1.3 x 10(7) M-1 was obtained for the hyaluronate-binding region of the proteoglycan, in agreement with literature data. The corresponding value for the link protein was 0.7 x 10(7) M-1.

Animals↗
PubMed1971

The fine structure of bovine nasal cartilage. Extraction as a technique to study proteoglycans and collagen in cartilage matrix.

Bovine nasal cartilage was studied by electron microscopy before and after extraction with 4 M guanidinium chloride or 1.9 M CaCl(2). These solvents removed matrix granules, basophilia, and 85% of the proteoglycan complex, measured as hexuronate. Simultaneously, many collagen fibrils were disaggregated into component microfibrils (approximately 40 A thick). In contrast to the above solvents, exhaustive extraction with 0.5 M guanidinium chloride removed 20% of the proteoglycan complex, and matrix granules were reduced in size but not in number. Extraction with 4 M CaCl(2) removed only 10% of the proteoglycan complex, did not remove matrix granules, and caused the normal banding pattern of collagen to disappear. The banding was restored by further treatment with trypsin. Trypsin, before or after 4 M CaCl(2), removed matrix granules and 90% of the proteoglycan complex. We conclude that matrix granules are an electron microscopic representation of the proteoglycan complex, and consist of more than one proteoglycan macromolecule. It would appear that 4 M guanidinium chloride and 1.9 M CaCl(2), in addition to removing most of the proteoglycan complex, also disaggregate some of the collagen fibrils into their component microfibrils.

Animals↗
PubMed1984

The effects of internal fixation on the articular cartilage of unfused canine facet joint cartilage.

Custom-made distraction instrumentation was placed in the lumbar spine of eight large dogs with care taken to preserve the integrity of two intervening apophyseal joints. Histologic staining of immobilized joint cartilage showed varying degrees of chondrolysis, cloning, invasion of the tide mark, and loss of proteoglycans as early as 2 months postoperatively. Every specimen had significant degenerative changes characteristic of osteoarthritis. The joints one segment caudal to the lower hooks also were examined and were found to have similar histologic evidence of degeneration. Three dogs had the instrumentation removed and were then sacrificed 1.5-3 months later. The degenerative changes were not reversible following instrumentation removal.

Animals↗
PubMed2005

Expressions of membrane-type I matrix metalloproteinase, Ki-67 protein, and type II collagen by chondrocytes migrating from cartilage endplate into nucleus pulposus in rat intervertebral discs: a cartilage endplate-fracture model using an intervertebral disc organ culture.

STUDY DESIGN: Immunohistochemistry was performed in organ-cultured intact and cartilage endplate (CE)-fractured rat intervertebral discs (IVDs). OBJECTIVES: To demonstrate biologic events associated with migration of chondrocytes from hyaline CE into nucleus pulposus (NP). SUMMARY OF BACKGROUND DATA: It was recently revealed that the transition from a notochordal NP to a fibrocartilaginous NP in the rabbit IVD is accomplished exogenously by chondrocytes migrating from CEs into the NP. This observation has not been studied in other animal models, and the biologic events associated with chondrocyte migration have not been elucidated in the literature. METHODS: IVDs including cranial and caudal CEs were obtained from 4-week, 6-month, 12-month, and 18-month old Wistar rats. To accelerate chondrocyte migration, CEs of IVDs were fractured and cultured for 48 hours. IVDs without CE-fracture were used as a control for each age group. Expressions of membrane-type I matrix metalloproteinase (MT1-MMP, as a marker for cell migration and extracellular matrix digestion) and Ki-67 protein (as a proliferation marker) and pericellular deposition of type II collagen (as a marker for fibrocartilaginous matrix) by the chondrocytes migrating from CE into NP were examined immunohistochemically. RESULTS: In the control groups, chondrocyte migration limited only along the periphery of the notochordal NP and no chondrocytes were inside the NP proper. However, all the IVDs in the CE-fracture groups showed direct and more extensive migration of chondrocytes from CEs into the NP proper. The migrating chondrocytes in both control and CE-fracture groups expressed MT1-MMP and Ki-67 protein and deposited type II collagen in the NP. CONCLUSIONS: This report demonstrates the chondrocyte migration from CE into NP in the organ-cultured rat IVDs. This phenomenon is accelerated in the presence of CE fracture. The chondrocytes migrating from CEs into the NP expressed MT1-MMP and Ki-67 protein and deposited type II collagen. These biologic strategies probably enable chondrocytes of the hyaline CE to migrate into the ectopic NP region, replace notochordal cells, and change the notochordal tissue into fibrocartilage. These results suggest that similar biologic mechanisms may be involved in the natural transition from the notochordal NP to the fibrocartilaginous NP in other animal models, including human.

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↗
PubMed2004

[Gene expression changes of cartilage matrix of condylar cartilage with anterior disc displacement].

OBJECTIVE: To study the gene expression changes in extracellular matrix of condylar cartilage following disc anterior displacement of rabbit TMJ. METHODS: The right sides of 28 joints in 40 rabbits were subjected to surgical operation of disc displacement. The condylar Collagen II and Aggrecan mRNA expression were detected by in situ hybridization. RESULTS: Collagen II and Aggrecan mRNA mainly expressed in the lower zone of condylar chondrocyte. Aggrecan mRNA decreased faster than collagen II following disc displacement, and adjusted to normal later. CONCLUSION: Anterior disc displacement leads to alteration of extracellurar matrix gene expression in the condylar chondrocyte, which means the start of remodeling.

Aggrecans↗
PubMed1985

Nicolas Andry Award, 1984. Deleterious interactions of immune complexes in cartilage of experimental immune arthritis. I. The erosion of pannus-free hyaline cartilage.

Immune complexes were detected by plain and immunoelectron microscopy amongst electron-dense material that rapidly formed and extended over and into the cartilaginous surfaces of immune arthritic rabbits' knees. The sinuous extension of electron-dense material into the surface matrix was associated with fragmentation and detachment, resulting in erosions. The findings implicate the formation of immune complexes in the destructive process of the matrix. Since the eroded pannus-free matrix of rheumatoid cartilage surfaces contains extensive concentrations of immune complexes, the data of this immune arthritis model suggest a causative relation between immune complexes and matrix loss in rheumatoid arthritis.

Animals↗
PubMed1980

Studies on cartilage formation. XXII. Investigations of certain oxidative metabolic processes in regenerating articular cartilage.

The distal articular surface of the femur was surgically removed in 57 dogs. Succinate dehydrogenase and cytochrome oxidase activities were assayed on postoperative days 7, 20, 26, 33 and 70 in the regenerating, chondrifying articular surface and in the granulation tissue adhering to the capsule. In the 70-day samples, the cyanide-induced inhibition of oxygen consumption was determined and enzyme histochemical reactions (cytochrome oxidase, monoamine oxidase, xanthine oxidase, peroxidase and "catalase") were performed. The succinate dehydrogenase activity was the highest in the early postoperative stage in both tissues. This was followed by a definite decrease and a subsequent significant increase in activity when chondrification took place. Measurement of cytochrome oxidase activity could not reveal any convincing result, presumably because of the properties of the tissues studied. The oxygen consumption by the chondrifying articular surface at 70 days was inhibited to about 50% by cyanide, and about 90% inhibition was observed in the tissue adhering to the capsule. The cells of the regenerating articular surface possess cytochrome oxidase and a cyanide- (and sodium azide-) resistant oxidase activity. The enzyme activity of the cartilaginous islets exceeded that of their connective tissue environment. The cytochrome oxidase activity increased in the cells during cartilage differentiation. Presumably, some further cyanide-sensitive and cyanide-resistant oxidases are present in chondroblasts and young chondrocytes.

Animals↗
PubMed1982

Human cartilage collagens. Comparison of cartilage collagens with human type V collagen.

Human hyaline cartilage contains three collagen chains in addition to the alpha 1(II) chain of Type II collagen. Two of these chains, tentatively designated the 1 alpha and 2 alpha chains, have been extensively characterized. Although similar in molecular weight to other collagen chains, by the combined criteria of solubility, electrophoretic mobilities, carboxymethylcellulose elution profiles, total amino acid compositions, carbohydrate contents, cyanogen bromide peptide profiles, limited V8 protease digestion profiles, and examination of selected cyanogen bromide peptides, the 1 alpha and 2 alpha chains are structurally unique collagen alpha chains. Because of similarities of the 1 alpha and 2 alpha chains to the alpha 1(V) and alpha 2(V) chains, respectively., of Type V collagen, specific comparisons between these collagen chains and their constituent peptides were made and yielded the conclusion that these chains are nonidentical, but share substantial similarities.

Amino Acids↗
PubMed1997

Sequential synthesis of cartilage and bone marker proteins during transdifferentiation of mouse Meckel's cartilage chondrocytes in vitro.

Meckel's cartilage cells cultured in vitro undergo phenotypic transformation toward osteogenic cells. We examined whether these cells synthesize type X collagen and bone morphogenetic protein-2 (BMP-2). We also examined the results of Alcian blue staining and the expression of type I and type II collagen, osteocalcin and chondroitin sulfate proteoglycan (CSPG) during this transdifferentiation. Meckel's chondrocytes, isolated from day-17 mouse embryos, were inoculated at 1 x 10(4)/penicylinder and cultured in alpha-MEM for periods up to 4 weeks. Alcian blue staining and immunostaining of type II collagen and CSPG confirmed that, after cell culture for 2 weeks, the cartilaginous phenotype was expressed most intensely. Later in culture, chondrocytes underwent modification through the synthesis of bone-type proteins; nodule-forming small round cells showed ALPase activity and were immunoreactive for type I collagen and osteocalcin. Immunoreactivity for type X collagen was detected in the small round cells at the top of the nodules prior to calcification of the matrix, as well as in large hypertrophic cells. BMP-2 was also expressed first in similar small round cells after 3 weeks in culture, and it subsequently extended along the extracellular matrix in the calcified nodules. These results indicate that small round cells that are differentiating toward osteocyte-like cells from Meckel's chondrocytes express type X collagen and BMP-2 sequentially.

Animals↗