Role of proteoglycans in the onset of calcification
The objective of this investigation was to inquire if the presence or absence of proteoglycans or their chemical subunits had a direct effect on the onset of calcification. High density spot cultures of limb bud mesenchyme obtained from mouse embryos on the 12th day of gestation were exposed to medium containing 30 mM phosphate. Calcium deposits observed after staining by the von Kossa method were confined to the non-cartilagenous intenodular areas. Electron microscopy illustrated that a large proportion of the calcium deposits were associated with collagen fibrils. A significant increase in the uptake of /sup 45/Ca was observed in cultures supplemented with 30 mM phosphate. Atomic absorption analysis of the cultures showed that they contained 2.00 ng calcium/ug DNA. Incorporation of /sup 3/H-glucosamine into glycosaminoglycans (GAG) was significantly reduced by phosphate and both extruded and cell associated GAG were affected. Exposure of mineralizing cultures to a biologically active anticalculus agent, ethane-1-hydroxy-1,1-diphosphonate, resulted in a significant reduction in /sup 45/Ca uptake, providing confidence that the culture did response as a biological system. These data suggest that under the conditions employed, proteoglycans in the extracellular environment of limb bud mesenchyme inhibit calcium deposition. The inhibitory effect was observed only when proteoglycans were added as polymeric aggregates. The culture system employed was unable to detect the inhibitory effects, if any, of proteoglycan monomers or the subunits of proteoglycans, hyaluronic acid or chondroitin sulfate.
- Research Organization:
- Thomas Jefferson Univ., Philadelphia, PA (USA)
- OSTI ID:
- 7170819
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
Similar Records
Purification and partial characterization of glycosaminoglycans and proteoglycans from cultured rabbit smooth muscle cells
Human glomerular epithelial cell proteoglycans
Related Subjects
CALCINOSIS
PHYSIOLOGY
CALCIUM 45
UPTAKE
GLUCOPROTEINS
BIOCHEMISTRY
ABSORPTION SPECTROSCOPY
EMBRYOS
GLUCOSAMINE
MICE
TRITIUM COMPOUNDS
ALKALINE EARTH ISOTOPES
AMINES
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CALCIUM ISOTOPES
CARBOHYDRATES
CHEMISTRY
DAYS LIVING RADIOISOTOPES
EVEN-ODD NUCLEI
HEXOSAMINES
HEXOSES
INTERMEDIATE MASS NUCLEI
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MONOSACCHARIDES
NUCLEI
ORGANIC COMPOUNDS
PATHOLOGICAL CHANGES
PROTEINS
RADIOISOTOPES
RODENTS
SACCHARIDES
SPECTROSCOPY
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
551001 - Physiological Systems- Tracer Techniques