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At least 19 recordsLinked to original sources

Mapping articular cartilage maturation across postnatal development by proteomics.

OBJECTIVE: Articular cartilage has a specialised extracellular matrix that provides tensile strength and resistance to compression, but repair capacity is limited. Matrix remodelling during growth is essential for long-term tissue function, yet the underlying protein-level adaptations remain poorly characterised in large-animal models relevant to human joint biology. DESIGN: Using non-targeted, label-free mass spectrometry-based proteomics, we profiled full-thickness articular cartilage from goats across seven postnatal ages from neonatal to adult (n = 3 per age). Cartilage proteins were extracted using guanidine-based solubilisation and analysed by mass spectrometry. Selected proteins were further examined by immunohistochemistry. RESULTS: We identified 799 proteins across the seven ages, of which 157 matrisome components grouped into six categories. Development was associated with increased abundance of proteins involved in matrix organisation and stabilisation, including COL6A1, LOX, TIMP3 and CILP. Enrichment analysis revealed a shift from collagen biosynthesis and fibrillogenesis in early postnatal cartilage to elastic fibre organisation, integrin-matrix interactions and glycosaminoglycan metabolism in mature tissue, consistent with transition from matrix assembly to maintenance. Lysozyme increased with age, suggesting a structural role that warrants further study. Several proteins enriched in mature cartilage, including CILP, HTRA1, FN1 and SPP1, have also been implicated in osteoarthritis, suggesting that some molecular features of mature ECM maintenance are shared with diseased tissue. Immunohistochemistry confirmed stable COL2 localisation, loss of deep-zone COL10 staining with maturation and emergence of superficial PRG4 expression in adult cartilage. CONCLUSIONS: Our findings define the proteomic trajectory of cartilage maturation and provide a molecular reference for joint development and matrix ageing.

Animals

Membrane changes during cartilage maturation. Increase in 5'-nucleotidase and decrease in adenosine inhibition of adenylate cyclase.

To examine the potential participation of the plasma membrane in differentiation, we studied the enzymatic activities of 5'-nucleotidase and adenylate cyclase as a function of chondrocyte maturation. 16-day-old chick embryo tibiae epiphyses were dissected into proliferative, growing and hypertrophying zones. Partially purified membrane fractions prepared by differential centrifugation from the respective tissue segments were assayed for enzymatic activity. Cell suspensions from the same segments were examined cytochemically for the presence of 5'-nucleotidase. The findings show that the 5'-nucleotidase activity of the chick embryo epiphyseal cartilage has the following characteristics: (a) it has a Km of about 25 muM for 5'AMP, and is inhibited by a mixture of 2' and 3'AMP (apparent Ki about 10(-4) M) and by AOPCP; (b) it is predominantly localized at the cell surface but is also detected in the cytoplasm and in association with nuclear heterochromatin; and (c) it increases 10-fold (on a DNA basis) during the maturation of the epiphyseal cartilage cells. The adenylate cyclase activity has these characteristics: (a) it does not change during chondrocyte maturation (on a DNA basis); (b) its susceptibility to adenosine inhibition decreases at least 10-fold. The implication of these findings relative to a possible role of adenosine in cellular communication is discussed.

Adenosine

Vitamin C regulation of cartilage maturation.

Treatment of chondrocytes with vitamin C under defined conditions in cell culture initiates a differentiation program that closely mimics the normal maturation of cells in the growth plate of long bones.

Animals

Type X collagen is transcriptionally activated and specifically localized during sternal cartilage maturation.

Type X collagen is an extracellular matrix protein which is synthesized by chondrocytes when they undergo hypertrophy. We present evidence here that the expression of type X collagen in the developing chick sternum is controlled primarily by transcriptional mechanisms. Using chondrocyte nuclei isolated from 15-, 16-, 17- and 18-day chick embryonic sterna, nuclear run-off assays demonstrate that type X collagen gene transcription begins at day 16 in chondrocytes isolated from the cephalic portion. This occurs two days prior to mineralization of this tissue as observed by alizarin red staining. The rate of type X transcription increases dramatically through days 17 and 18. Western blot analyses of extracts of freshly isolated sternal chondrocytes from the same stages show that intracellular levels of the type X protein follow the same time course. Immunostaining with a monoclonal antibody specific for type X collagen demonstrates that the initial appearances of hypertrophic cells and pericellular type X collagen occur at embryonic day 16 in the cephalic portion of sterna. Observation of immunostained cephalic sternal sections from day 18 embryos by confocal microscopy reveals that type X collagen is localized in a capsule-like configuration around each hypertrophic chondrocyte.

Animals

Structural and histochemical aspects of the pericellular environment in cartilage.

Mature cartilage contains pericellular regions of matrix of fine texture, consisting of filamentous material and granules containing proteoglycan. Intercellular matrix contains collagen fibres with structural elements resembling those of the pericellular regions in the spaces between the fibres. Membrane bound bodies may be present at the margin of the pericellular region. Histochemically, chondroitin sulphate is found in the pericellular region in all zones but keratan sulphate is similarly stainable only in the deep zones of ageing cartilage.

Adult

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

Thermoanalytical and histological study of intra-articular papain-induced degradation and repair of rabbit cartilage. II. Mature animals.

The effect of papain treatment on the cartilage tissue of the knee joint of mature rabbits was studied by histological and thermoanalytical methods. Changes taking place in the composition of cartilage in the course of ageing were shown. As a result of papain treatment a significant irreversible destruction of the ground substance took place. Papain-induced loss of proteoglycans and the intensity of repair reactions and age-related differences are discussed.

Aging

A maturation change in the surface of cat articular cartilage detected by the scanning electron microscope.

The articular surface of the femoral condyle of kittens (2 days to 2 months old) and cats (6 months to 20 months old) was studied by examining air dried and critical point dried specimens in the scanning electron microscope. The surface of kitten cartilage was found to be populated by innumerable humps which were more prominent in air dried than in critical point dried specimens. Undulations and ridges were seen on air dried kitten cartilage, which was markedly shrunken and distorted, but undulations and ridges were absent from critical point dried specimens where shrinkage was more modest or even undetectable. The surface of the articular cartilage of 12 months and 20 months old cats was populated by innumerable pits. A rare hump in a pit was seen in specimens from the 12 months old cat, but not from the 20 months old animal. In 6--8 months old cats an intermediate situation prevails, for in some specimens pits were present on the posterior part of the condyle but humps and humps in pits were present on the anterior aspect. This study shows that the surface of young articular cartilage is populated by humps, but as the cartilage matures these formations are either transformed into pits or replaced by pits.

Age Factors

Scattered mitoses in mature joint cartilage in rabbits after local trauma. A chalone effect?

This is a demonstration of local traumatization of articular cartilage inducing mitoses in parts of a joint other than the site of inquiry. Parts of one of the patellar cartilages of the full-grown rabbit were scored while the other knee was subjected only to arthrotomy. Radioactive thymidine and autoradiographic technique demonstrated that labeled chondrocytes appeared not only around the score in the patella but also scattered in the tibia and femoral condyles. Whether the mechanism of regional mitotic stimulation is a reduction of the concentration of the normal cell specific inhibitors of mitosis, or so-called chalones is not known and requires further investigation.

Animals

Morphology of the perforating cartilage canals in the proximal tibial growth plate of the chick.

Perforating canals arise exclusively from junctional canals just above the reserve zone and they do not branch after entering the proliferative zone. They are uniformly spaced and arranged in parallel array. The cartilage canals terminate near the beginning of the zone of hypertrophic cartilage cells. Vascular components within the perforating canals consist of a central arteriole surrounded by enlarged, interconnected capillaries which are individually in contact with the adjacent cartilage matrix. TEM shows that the capillary endothelium is extremely attenuated, possesses numerous fenestrations and lacks a continuous basement membrane. The central arteriole is enlarged through the midpart of the canal and then narrows to communicate with the capillaries near the bottom of the canal. The large capillaries ascend from their point of origin and recombine near the top of the growth plate to exit as a single venule. The vascular arrangement therefore describes a system in which the outgoing blood runs in close proximity, but counter to, the incoming blood. This vascular arrangement within the perforating cartilage canal would most likely allow the zone of maturing cartilage cells to receive the highest concentration of nutrients.

Animals

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

Osteochondritis dissecans in the dog: diagnosis and therapy.

Osteochondritis dissecans (OCD) is a manifestation of osteochondrosis. It is thought to be a metabolic disease of cartilage maturation and endochondral ossification. Therefore, any disturbance affecting the differentiation of growth cartilage constitutes osteochondrosis. When this disturbance affects the articular cartilage so that a piece detaches, it is called OCD. Osteochondritis dissecans is well recognized but poorly understood. The etiology remains controversial. Osteochondritis dissecans is most commonly recognized in the shoulder but can occur in other areas which makes it difficult to differentiate from other disease entities. Diagnosis of OCD is based on signalment (age, breed, and sex), history, and physical and radiographic evidence. Therapy must be individualized and based on the patient's clinical signs and not on the severity of the radiographic lesion. Therapy can be effective only when applied correctly.

Animals

Benign chondrolipomatous tumor of the human female breast.

A benign chondrolipomatous breast tumor occurred in a 66-year-old woman. The preoperative diagnosis, based on mammography and xeroradiography, was fibroadenoma. Grossly, the demarcated lesion resembled a fibroadenoma with islands of cartilage projecting from its cut surface. Histologically, it was composed of benign mature fibrous stroma, fat, breast ducts, and islands of mature cartilage. Most cartilage-containing tumors of the human breast are associated with primary mammary malignant neoplasms. A few of the benign cartilage-containing tumors reported in the literature are discussed. The last case was published in 1909.

Adenofibroma

Human articular cartilage in relation to age, A morphometric study.

The cell density of the weight-bearing area of normal femoral head cartilage was investigated in 65 cases of both sexes ranging from 6 to 90 years of age. In the maturing cartilage (until about the third decade), the cell density decreases, while in aging cartilage (30-90 years) it remains constant. Our results are in agreement with the main trend of earlier and similar investigations. The reason for contradictory reports is suggested to be due to differences in the selection of criteria for defining 'normal' cartilage. This problem is particularly acute with advancing age, where a great part of the available material shows degenerative changes.

Adolescent

Amplification of moderately repetitive DNA sequences during chick cartilage differentiation.

A 5-bromo-2'-[3H]deoxyuridine (BrdUrd) probe was isolated to analyze DNAs obtained from various chick tissues and cell types. [3H]BrdUrd-substituted DNA, prepared from limb bud cultures, was sheared and freed from palindromic DNA. Nonradioactive DNA was prepared from embryonic liver, undifferentiated limb bud mesenchyme, sternal cartilage, differentiated limb bud cultures, and BrdUrd-blocked cultures, and was sheared. These DNAs were used in 100-fold excess to drive the reassociation of the [3H]-BrdUrd-DNA probe. Purified mature cartilage DNAs of embryonic sternae or differentiated limb bud cultures drove the reassociation of the probe approximately two times faster than did DNA from liver, undifferentiated limb bud, or BrdUrd-blocked cells. These data indicate that cartilage DNA contains a greater number of sequences complementary to the BrdUrd probe than do DNAs of noncartilage or undifferentiated precartilage cells. Calculations determined an average substitution of 10% of thymidine residues by BrdUrd in purified probe, whereas CsCl density gradients of unsheared probe revealed radioactive peaks of greater than 20% substitution. The BrdUrd appears to be clustered in the genome.

Alleles

The effect of glucose-1 phosphate calcium on the epiphyseal cartilage of the rat.

Electron microscopic investigations were carried out on the proximal tibial epiphyseal cartilage of albino rats treated with 2 mg G-1-P-Ca daily for one and three weeks. The treatment--enhanced the secretory activity of the upper cells of the zone of maturing cartilage with a consequential enlargement of the Golgi region, depletion of secretory products, and an increase in the number of microtubuli. --In addition, the treatment increased the number of matrix vesicles in the extracellular space showing incipient calcification. This findings confirm the earlier light micriscopic observation of the calcification stimulating effect of G-1-P-Ca.

Animals

The pathogenesis of cauliflower ear. An experimental study in rabbits.

Appreciating an imcomplete understanding of the pathogenesis of cauliflower ear, an experimental study was designed to demonstrate the pathophysiology of this deformity. The investigation was conducted in 2-month-old rabbits. In one ear a collection of blood was placed under the raised perichondrium which was then sutured back in place and the skin closed. In the other ear an equal amount of blood was deposited between the intact perichondrium and skin. In the first study new cartilage developed under the perichondrium, but in the ear in which the blood was left above the surface of the perichondrium-covered cartilage, complete resorption of the clot occurred. The cauliflower ear was thus shown to be generating cartilage, arising from a layer of raised perichondrium which was further stimulated by a sero-sanguinous medium. The subperichondrial hematoma was extensively invaded by chondroblasts within 2 weeks, and over a period of 4 weeks the new tissue gradually changed into more mature cartilage. It was a consistent finding that the separated perichondrium retracted, thus causing the original cartilage to rise and buckle over the hamatoma, similar to the picture observed in the human pathology.

Animals