scholarly journals Synthesis of hyaluronate in cultured bovine articular cartilage

1989 ◽  
Vol 263 (3) ◽  
pp. 761-767 ◽  
Author(s):  
C K Ng ◽  
C J Handley ◽  
R M Mason ◽  
H C Robinson
Keyword(s):  
Articular Cartilage ◽  
Deep Layer ◽  
Superficial Layer ◽  
Explant Culture ◽  
Proteoglycan Synthesis ◽  
Hydrodynamic Size ◽  
Short Term ◽  
Bovine Articular Cartilage ◽  
Sulphated Glycosaminoglycans ◽  
Two Populations

The synthesis and distribution of hyaluronate and proteoglycan were studied in bovine articular cartilage in short-term explant culture with [3H]acetate and H2(35)SO4 as precursors. The incorporation of [3H]acetate into hyaluronate and sulphated glycosaminoglycans was linear with time, except that hyaluronate synthesis showed a marked lag at the beginning of the incubation. [3H]Hyaluronate represented 4-7% of the total [3H]glycosaminoglycans synthesized over a 6 h period. However, the distributions of [3H]hyaluronate and 3H-labelled sulphated glycosaminoglycans were different: about 50% of the newly synthesized [3H]hyaluronate appeared in the medium, compared with less than 5% of the 3H-labelled sulphated proteoglycans. A pulse-chase experiment revealed that the release of newly synthesized [3H]hyaluronate from cartilage was rapid. No difference was observed in the distribution of [3H]hyaluronate between medium and tissue by cartilage from either the superficial layer or the deep layer of articular cartilage. When articular cartilage was incubated with 0.4 mM-cycloheximide, proteoglycan synthesis was markedly inhibited, whereas the synthesis of hyaluronate was only partially inhibited and resulted in more of the newly synthesized hyaluronate being released into the medium. Analysis of the hydrodynamic size of [3H]hyaluronate isolated from cartilage on Sephacryl-1000 revealed one population that was eluted as a broad peak (Kav. less than 0.7), compared with two populations (Kav. greater than 0.5 and less than 0.5) appearing in the medium of cultures. These data suggest that hyaluronate is synthesized in excess of proteoglycan synthesis and that the hyaluronate that is not complexed with proteoglycans is rapidly lost from the tissue.

The Micro-Mechanical Behavior of Articular Cartilage under Continuous Sliding Load

2013 ◽  
Vol 395-396 ◽  
pp. 654-657
Author(s):  
Peng Peng Xiao ◽  
Li Lan Gao ◽  
Zhi Dong Liu ◽  
Chun Qiu Zhang
Keyword(s):  
Articular Cartilage ◽  
Connective Tissue ◽  
Deep Layer ◽  
Compressive Strain ◽  
Middle Layer ◽  
Superficial Layer ◽  
Image Correlation ◽  
Daily Activities ◽  
Normal Displacement ◽  
Dic Technique

As a viscoelastic and nonlinear connective tissue, articular cartilage bears continuous sliding load in the daily activities. The optimized digital image correlation (DIC) technique was applied to investigate the effect of sliding rate and compressive strain on the normal displacement of different layers in pig articular cartilage under sliding load. The normal displacements of different layers in cartilage increase gradually with sliding going on with given sliding rate and compressive strain. Experiments showed that the normal displacement of superficial layer is the largest, the normal displacement of deep layer is the smallest and the normal displacement of middle layer is between superficial layer and deep layer, and found that the normal displacements of different layers in cartilage increase with increasing compressive strains, but decrease with increasing sliding rates. The normal displacement of different layers are different under continuous sliding load.

scholarly journals Stimulation of proteoglycan biosynthesis by serum and insulin-like growth factor-I in cultured bovine articular cartilage

1986 ◽  
Vol 240 (2) ◽  
pp. 423-430 ◽  
Author(s):  
D J McQuillan ◽  
C J Handley ◽  
M A Campbell ◽  
S Bolis ◽  
V E Milway ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Growth Factor ◽  
Calf Serum ◽  
Proteoglycan Synthesis ◽  
Foetal Calf Serum ◽  
Insulin Like Growth Factor ◽  
Bovine Articular Cartilage ◽  
Factor I ◽  
Igf I ◽  
Growth Factor I

The addition of foetal calf serum to explant cultures of adult bovine articular cartilage is known to stimulate proteoglycan synthesis in a dose-dependent manner. We have now shown the activity in serum responsible for this effect to be heat- and acid-stable, to be associated with a high-Mr complex in normal serum but converted to a low-Mr form under acid conditions. The activity has an apparent Mr approximately 10,000 and isoelectric points similar to those reported for insulin-like growth factors (IGFs). Addition of a monoclonal antibody against insulin-like growth factor-I (IGF-I) prevented foetal calf serum from stimulating proteoglycan synthesis. Physiological concentrations of recombinant IGF-I or pharmacological levels of insulin when added to cartilage cultures mimicked the proteoglycan-stimulatory activity of serum. IGF-I appeared to act by increasing the rate of proteoglycan synthesis and did not change the nature of the proteoglycan synthesized nor the rate of proteoglycan catabolism by the tissue, suggesting that IGF-I may be important in the regulation of proteoglycan metabolism in adult articular cartilage. Furthermore, IGF-I can replace foetal calf serum in the culture medium, thereby allowing the use of a fully-defined medium which will maintain the synthesis and tissue levels of proteoglycan in adult articular cartilage explants for up to 5 days.

scholarly journals Effects of radiopharmaceuticals on articular cartilage’s mechanical properties

Nukleonika ◽  
2019 ◽  
Vol 64 (2) ◽  
pp. 71-74
Author(s):  
Nihal Kuzu ◽  
Ekrem Cicek
Keyword(s):  
Mechanical Properties ◽  
Articular Cartilage ◽  
Ionizing Radiation ◽  
Mechanical Tests ◽  
Cartilage Tissue ◽  
Proteoglycan Synthesis ◽  
Bovine Articular Cartilage ◽  
Technetium 99M ◽  
Static Mechanical ◽  
Radiation Science

Abstract As radiation science and technology advances, nuclear medicine applications are increasing worldwide which necessitate the understanding of biological implications of such practices. Ionizing radiation has been shown to cause degraded matrix and reduced proteoglycan synthesis in cartilage, and the late consequences of which may include degenerative arthritis or arthropathy. Although degenerative effects of the ionizing radiation on cartilage tissue have been demonstrated, the effects on the mechanical properties of articular cartilage are largely unknown. The radiopharmaceuticals, technetium-99m and technetium-99m sestamibi, were utilized on bovine articular cartilage to investigate these effects. We used two different mechanical tests to determine the mechanical properties of articular cartilage. Dynamic and static mechanical tests were applied to calculate compressive modulus for articular cartilage. We observed clearly higher control modulus values than that of experimental groups which account for lesser stiffness in the exposed cartilage. In conclusion, compressive moduli of bovine articular cartilage were found to decrease after radiopharmaceutical exposure, after both instantaneous and equilibrium mechanical experiments.

Subpopulations of chondrocytes from different zones of pig articular cartilage. Isolation, growth and proteoglycan synthesis in culture

1990 ◽  
Vol 97 (2) ◽  
pp. 349-360
Author(s):  
M. Siczkowski ◽  
F.M. Watt
Keyword(s):  
Articular Cartilage ◽  
Articular Surface ◽  
Polyacrylamide Gel Electrophoresis ◽  
Proteoglycan Synthesis ◽  
Lower Zone ◽  
Keratan Sulphate ◽  
Sulphate Content ◽  
Plating Density ◽  
Morphological Differences ◽  
Two Populations

Articular cartilage varies in ultrastructure and composition with distance from the articular surface. We have cultured chondrocytes from different zones of pig articular cartilage and investigated whether there are intrinsic differences in their behaviour that might account for the variation observed in intact tissue. On isolation, cells from the upper third of the cartilage were smaller than those of the lower third, but this difference was not maintained in culture. Upper zone cells attached and spread more slowly than lower zone cells; morphological differences between the two populations could be seen for several weeks. The growth rates of the two populations were similar, but upper zone cells reached a lower confluent density. Levels of protein synthesis were similar for both populations, but upper zone cells deposited less proteoglycan in the cell layer. On isolation, the percentage of upper zone cells that stained positive with MZ15, a monoclonal antibody to keratan sulphate, was smaller than the percentage of lower zone cells, but this difference was lost after several days in culture. Nevertheless, the keratan sulphate content of proteoglycan synthesised by lower zone chondrocytes at high density was greater than of that synthesised by upper zone cells. The proportion of nonaggregating proteoglycan was greater in upper than lower zone cartilage and this difference was also observed in long-term cultures. proteoglycans were further characterised by composite and polyacrylamide gel electrophoresis and by immunoblotting; differences detected in cartilage extracts were not, however, maintained in culture; instead, the small proteoglycans synthesised by both upper and lower zone cells varied with plating density. Finally, alkaline phosphatase, a marker of hypertrophic, calcifying cartilage, was only expressed in lower zone cultures. We conclude that some of the observed heterogeneity of articular cartilage reflects intrinsic differences between the cells of different zones, whereas some may reflect the response of chondrocytes to different environmental conditions.

scholarly journals Control of proteoglycan biosynthesis. Further studies on the effect of serum on cultured bovine articular cartilage

1986 ◽  
Vol 237 (3) ◽  
pp. 741-747 ◽  
Author(s):  
D J McQuillan ◽  
C J Handley ◽  
H C Robinson
Keyword(s):  
Articular Cartilage ◽  
Dna Synthesis ◽  
Half Life ◽  
Rna Synthesis ◽  
Core Protein ◽  
Calf Serum ◽  
Proteoglycan Synthesis ◽  
Foetal Calf Serum ◽  
Bovine Articular Cartilage ◽  
Stimulation Of

Proteoglycan synthesis in explant cultures of adult bovine articular cartilage is stimulated in a dose-dependent manner when the tissue is cultured in the presence of foetal-calf serum. The stimulation of proteoglycan synthesis is paralleled by a similar increase in DNA synthesis; however, when DNA synthesis is inhibited by hydroxyurea the stimulation of proteoglycan synthesis by serum remains essentially the same. The apparent half-life of the pool of proteoglycan core protein precursor was measured in freshly isolated tissue as well as in tissue cultured for 7 days in the presence and in the absence of foetal-calf serum; under all conditions the half-life was the same, suggesting that this value is independent of the net rate of proteoglycan synthesis. In the presence of actinomycin D, an inhibitor of RNA synthesis, there was a difference in the apparent half-life of the available pool of mRNA coding for proteoglycan core protein: 8.5 h for tissue maintained in the presence of serum and 3.8 h for tissue cultured in the absence of serum. It is suggested that proteoglycan synthesis is stimulated by serum factors at the level of DNA-dependent RNA synthesis. Concomitant with an increase in the rate of proteoglycan synthesis induced by the presence of serum in the culture medium, an increase in the concentrations of several glycosyltransferases involved in chondroitin sulphate synthesis was also observed.

Structural studies of two populations of keratan sulphate chains from mature bovine articular cartilage

1989 ◽  
Vol 6 (2) ◽  
pp. 209-218 ◽  
Author(s):  
David J Thornton ◽  
Haydn G Morris ◽  
Gordon H Cockin ◽  
Thomas N Huckerby ◽  
Ian A Nieduszynski
Keyword(s):  
Articular Cartilage ◽  
Structural Studies ◽  
Keratan Sulphate ◽  
Bovine Articular Cartilage ◽  
Two Populations
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