chondroitin-sulfates and Vitamin-D-Deficiency

Mandibular condylar cartilage from normal and low phosphate-vitamin D deficient rats were investigated by lectin histochemistry utilizing wheat germ agglutinin (WGA). We obtained the following results: 1) The cartilage from low phosphate-vitamin D deficient animals consisted predominantly of hypertrophic chondrocytes with abundant extracellular matrix. 2) The territorial matrix of the hypertrophic cell zone of normal cartilage was intensely labelled with WGA, whereas the binding affinity of this region in low phosphate-vitamin D deficient animals was significantly diminished. 3) Compared to normal cartilage, WGA binding sites were demonstrated in the inter-territorial matrix of low phosphate-vitamin D deficient animals to a moderate degree. 4) Abolishment of the territorial WGA binding affinity in low phosphate-vitamin D deficient animals was presumed to indicate the accumulation of chondroitin sulfate which is believed to be a strong chelator of calcium ion.

Topics: Animals; Binding Sites; Cartilage, Articular; Chondroitin Sulfates; Extracellular Matrix; Mandibular Condyle; Phosphates; Rats; Vitamin D Deficiency; Wheat Germ Agglutinins

The composition of proteoglycans and glycosaminoglycans in two portions of the rat epiphyseal growth cartilage in florid and healing low phosphate, vitamin D deficiency rickets was studied. The concentration of both chondroitin sulfate and keratan sulfate was reduced with about 25 per cent in the lower (mineralizing) part of the growth plate in healing rickets compared to the lower (hypertrophic) part in florid rickets. In all samples about 85 per cent of the chondroitin sulfate chains had a sulfate ester group in the fourth position. Both in florid and healing rickets only one main population of polydisperse proteoglycans was found. In florid rickets the capacity to form aggregates with hyaluronic acid was the same in the upper and lower parts of the growth plate. With the onset of mineralization in healing rickets, however, a substantial decrease in this aggregability was demonstrated. These results give further support to the hypothesis that proteoglycans and, especially, proteoglycan aggregates, play a role in the mineralization process.

Topics: Animals; Chondroitin Sulfates; Glycosaminoglycans; Growth Plate; Hyaluronic Acid; Keratan Sulfate; Male; Minerals; Phosphates; Proteoglycans; Rats; Rickets; Tissue Distribution; Vitamin D; Vitamin D Deficiency

The concentration of inorganic sulfate-sulfur in the serum of vitamin D-deficient rats, 2.6 to 3.5 mg. per cent, was found to be higher than that in the serum of normal rats of the same age, 2.0 mg. per cent. No change was observed following the administration of 25 gamma of vitamin D(2). In accord with the results of others, it was found that a definitely increased deposition of phosphorus in femurs and tibiae had occurred 36 to 48 hours after the administration of vitamin D(2) to vitamin D-deficient rats. An immediate increase in the uptake of sulfate by the skeleton was found using sodium sulfate-S(35). As measured by the specific activity of sulfate-sulfur in samples of chondroitin sulfate isolated from the skeletons of the vitamin D-deficient animals and from normal controls receiving equal doses of sulfur-35, the rate of synthesis of chondroitin sulfate in rachitic rats is similar to the rate in normal rats of the same age. Likewise, the incorporation of labelled sulfate into the sulfomuco-polysaccharides of the pelts was found to be equal at 12 hours to that in normal rats. Following the administration of vitamin D(2) to deficient animals an increase in the rate of synthesis of the chondroitin sulfate of the skeletons was noted. The radiochemical and radioautographic evidence suggest that there is in vitamin D-deficient rats an impaired utilization of chondroitin sulfate and that vitamin D(2) is able to accelerate this process.

Topics: Animals; Cartilage; Chondroitin Sulfates; Ossification, Heterotopic; Osteogenesis; Phosphorus; Phosphorus Radioisotopes; Rats; Sulfates; Sulfur; Sulfur Radioisotopes; Vitamin A; Vitamin D; Vitamin D Deficiency; Vitamins