Proteoglycans of the knee-joint cartilage of young normal and lame pigs

Šimůnek, Z.; Muir, Helen

doi:10.1042/bj1300181

Cited by 22 publications

(10 citation statements)

References 25 publications

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“…In agreement with these results is the fact that, when diseased cartilage from dogs with naturally occurring or experimentally induced O A was extracted with 2 M calcium chloride, yields of PGs were approximately twice those obtained from normal cartilage (8). Comparable results have also been obtained with cartilage from lame pigs that had been reared intensively with restricted activity but that did not have OA (25). These data all suggest an abnormality of PG aggregation, a possibiiity that is supported by comparison of the aggregated PGs of normal and O A cartilage in the present study, in which aggregates from the diseased cartilage tended to be smaller than normal.…”

Section: Discussionsupporting

confidence: 76%

Organization of ground substance proteoglycans in normal and osteoarthritic knee cartilage

Brandt

Palmoski

1976

Arthritis & Rheumatism

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A study of the organization of proteoglycans in articular cartilage indicates that nonaggregated proteoglycans existed in larger numbers in osteoarthritic than in normal cartilage and that proteoglycan aggregates in arthritic cartilage were smaller than normal. After dissociation from hyaluronic acid and tissue glycoproteins, no difference in hydrodynamic size of disaggregated proteoglycans was noted, but chondroitin sulfate chains of those from diseased cartilage were shorter than normal. The data suggest that there is a defect in proteoglycan aggregation in osteoarthritic cartilage which could be of pathogenetic significance.The mechanical properties (eg stiffness on compression) that permit articular cartilage to subserve its From the Arthritis and Connective Tissue Disease Section,

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Section: Discussionsupporting

confidence: 76%

Organization of ground substance proteoglycans in normal and osteoarthritic knee cartilage

Brandt

Palmoski

1976

Arthritis & Rheumatism

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“…The proportion and size of the small non-aggregating proteoglycans remaining in the partially depleted explants is typical of proteoglycan extracted with low ionic strength buffers from several types of cartilage (Tsiganos & Muir, 1969;Hardingham & Muir, 1976;Simunek & Muir, 1972;Heinegard, 1977). The average molecular size of this material is very similar to that recovered from the medium and it is not clear why such molecules remain within the cartilage.…”

Section: Discussionmentioning

confidence: 98%

Chondrocyte-mediated depletion of articular cartilage proteoglycans in vitro

Tyler¹

1985

Biochemical Journal

146

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The degradation of proteoglycan was examined in cultured slices of pig articular cartilage. Pig leucocyte catabolin (10 ng/ml) was used to stimulate the chondrocytes and induce a 4-fold increase in the rate of proteoglycan loss from the matrix for 4 days. Material in the medium of both control and depleted cultures was mostly a degradation product of the aggregating proteoglycan. It was recovered as a very large molecule slightly smaller than the monomers extracted with 4M-guanidinium chloride and lacked a functional hyaluronate binding region. The size and charge were consistent with a very limited cleavage or conformational change of the core protein near the hyaluronate binding region releasing the C-terminal portion of the molecule intact from the aggregate. The 'clipped' monomer diffuses very rapidly through the matrix into the medium. The amount of proteoglycan extracted with 4M-guanidinium chloride decreased during culture from both the controls and depleted cartilage, and the average size of the molecules initially remained the same. However, the proportion of molecules with a smaller average size increased with time and was predominant in explants that had lost more than 70% of their proteoglycan. All of this material was able to form aggregates when mixed with hyaluronate, and glycosaminoglycans were the same size and charge as normal, indicating either that the core protein had been cleaved in many places or that larger molecules were preferentially released. A large proportion of the easily extracted and non-extractable proteoglycan remained in the partially depleted cartilage and the molecules were the same size and charge as those found in the controls. There was no evidence of detectable glycosidase activity and only very limited sulphatase activity. A similar rate of breakdown and final distribution pattern was found for newly synthesized proteoglycan. Increased amounts of latent neutral metalloproteinases and acid proteinase activities were present in the medium of depleted cartilage. These were not thought to be involved in the breakdown of proteoglycan. Increased release of proteoglycan ceased within 24h of removal of the catabolin, indicating that the effect was reversible and persisted only while the stimulus was present.

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“…Several processes occur during the maturation of articular cartilage: the amount of collagen increases (62)(63)(64)(65), the amount of PG decreases (62)(63)(64), cellularity diminishes (62,66) and the size of the cartilage is greatly reduced (62,63,66). Whereas in the newborn the collagen fibers are randomly oriented (67,68), during maturation they gradually align according to the zonal architecture shown in Fig.…”

Section: Study Of the Maturation Of Pig Articular Cartilagementioning

confidence: 99%

Multinuclear NMR and microscopic MRI studies of the articular cartilage nanostructure

Shinar

Navon

2006

NMR in Biomedicine

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Studies of the structure of articular cartilage by a number of NMR spectroscopic and imaging techniques are reviewed. Advantage is taken of the fact that the NMR investigations can be done non-invasively on the intact tissue and do not require sectioning, slicing and decalcification as in the case of electron microscopy. The different contributions to 1 H T 2 relaxation are described and it is pointed out that ignoring the biexponential behavior of the transverse relaxation can lead to serious errors in the proton density measurements and the T 2 characterization of the articular cartilage. A way to slow the transverse relaxation and to minimize its angular dependence by the use of dipolar echo is described. 2 H double quantum filtered spectroscopic MRI is a powerful technique to follow the orientation and density of the collagen fibers in articular cartilage. Using this technique, it was found that attachment of the cartilage to the bone has a stabilizing effect on the collagen matrix and that the hydroxyapatite in the calcified zone resides near the collagen fibers but does not contribute to their order. In response to mechanical pressure, it was shown that the collagen fibers flatten near the surface and become crimped near the bone. A number of NMR techniques have been described for the measurement of 23 Na residual quadrupolar interaction. It was found that this can serve as a very sensitive measure of the depletion of proteoglycans. Finally, a combination of the above techniques was used to study a maturation of articular cartilage in pigs. The increased order and density of the collagen fibers from newborn to adult pigs revealed itself as a shortening of T 2 and significant increase of the residual quadrupolar interaction of both 2 H and 23 Na nuclei.

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Proteoglycans of the knee-joint cartilage of young normal and lame pigs

Cited by 22 publications

References 25 publications

Organization of ground substance proteoglycans in normal and osteoarthritic knee cartilage

Organization of ground substance proteoglycans in normal and osteoarthritic knee cartilage

Chondrocyte-mediated depletion of articular cartilage proteoglycans in vitro

Multinuclear NMR and microscopic MRI studies of the articular cartilage nanostructure

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