Vertical distribution of elements in cells and matrix of epiphyseal growth plate cartilage determined by quantitative electron probe analysisTE Hargest, CV Gay, H Schraer and AJ Wasserman
Quantitative electron probe analysis was performed on chick epiphyseal growth cartilage prepared by two anhydrous methods, ultrathin cryosections and freeze-dried epoxy-embedded tissue. Levels of Na, Mg, P, S, Cl, K, and Ca were determined in cytoplasm, mitochondria, extracellular matrix, matrix vesicles, and mineral nodules in four zones of the cartilage--proliferative, prehypertrophic, early hypertrophic, and early calcification. The exceptionally high levels of Na and K (up to 550 and 200 mmol/kg wet wt, respectively) found in the matrix are believed to be largely bound to fixed anions. Within cells, Na was higher than K (140 versus 20-34 mmol/kg wet wt), a condition that may reflect hypoxia. Ca and P were low in cells and unmineralized matrix. Ca and P were high in mitochondrial granules of the early hypertrophic zone and diminished in amount in the calcifying zone; the converse occurred in matrix vesicles. Mg was low to undetectable except in heavily mineralized structures (i.e., mitochondrial granules, matrix vesicles, and mineral nodules). S levels were high in matrix (approximately 400 mmol/kg wet wt) and increased slightly with maturation. The amount of S present greatly exceeds Ca levels and implies that sulfate, the predominant form of sulfur in proteoglycans, may serve as an ion-exchange mechanism for the passage of Ca through the matrix to sites where Ca and phosphate are precipitated.
Volume 33,
Issue 4,
pp. 275-286,
04/01/1985
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C. B. Little, C. T. Meeker, R. M. Hembry, N. A. Sims, K. E. Lawlor, S. B. Golub, K. Last, and A. J. Fosang Matrix Metalloproteinases Are Not Essential for Aggrecan Turnover during Normal Skeletal Growth and Development Mol. Cell. Biol., April 15, 2005; 25(8): 3388 - 3399. [Abstract] [Full Text] [PDF] |
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J. Sela, U.M. Gross, D. Kohavi, J. Shani, D.D. Dean, B.D. Boyan, and Z. Schwartz Primary Mineralization At the Surfaces of Implants Critical Reviews in Oral Biology & Medicine, January 1, 2000; 11(4): 423 - 436. [Abstract] [Full Text] [PDF] |
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K. Rosenberg, H. Olsson, M. Morgelin, and D. Heinegard Cartilage Oligomeric Matrix Protein Shows High Affinity Zinc-dependent Interaction with Triple Helical Collagen J. Biol. Chem., August 7, 1998; 273(32): 20397 - 20403. [Abstract] [Full Text] [PDF] |
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