Lipid analysis of rat enamel and dentine

Prout, R.E.S.; Odutuga, A.A.; Tring, F.C.

doi:10.1016/0003-9969(73)90161-1

Cited by 66 publications

(14 citation statements)

References 18 publications

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“…In addition, Dirksen and Ikels (1964) were the first to establish that certain lipid classes were not extracted from dentin samples unless the samples are demineralized by EDTA or by carious decay. This was confirmed by Shapiro et al (1966) in fetal bovine dental tissues, and by Prout et al (1973) in rat teeth. However, interpretation of extraction data must take into account that some components may not, in vivo, be in contact with the mineral phase.…”

Section: (I) Concentration and Distribution Of Lipids In Enamel And Dsupporting

confidence: 55%

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Phospholipids in Amelogenesis and Dentinogenesis

Goldberg¹,

Septier²

2002

Critical Reviews in Oral Biology & Medicine

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ABSTRACT:Phospholipids have been identified in enamel and dentin. Before demineralization, a group of phospholipids extracted by lipid solvents was associated with cell membranes and is therefore closely related to cell growth and intracellular regulations. After demineralization, a second group of phospholipids, associated with the extracellular matrix, was extracted; this group is probably linked to the mineralized phase. Using imidazole-osmium tetroxide fixation of rat incisors, we stained cellular unsaturated fatty acids, so that we could visualize the membrane domains, coated pits, and endocytic inclusions. Filipin, a probe for cholesterol, varied in density along the plasma membrane of secretory ameloblasts, and allowed us to visualize membrane remnants inside the forming enamel. With respect to phospholipids located in the extracellular matrix, the malachite-green-glutaraldehyde (MGA) method or iodoplatinate (IP) reaction retains and visualizes enamel and dentin phospholipids. In predentin, aggregates appearing as granules and filaments, or liposome-like structures, were located in the spaces between collagen fibrils. In dentin, organic envelopes coating the crystals, also named "crystal-ghost" structures, outlined groups of collagen fibrils. Histochemical data provided evidence that phospholipids are co-distributed or interact with proteoglycans. Radioautography after IP reaction established that [ 3 H] choline was detected in dentin as early as 30 min after the intravenous injection of the labeled precursor, before any labeling was seen in odontoblasts and predentin. This suggests that bloodserum-labeled phospholipids pass between odontoblasts, cross the distal permeable junctional complex, and diffuse in dentin prior to any cellular uptake and phospholipid synthesis. Pharmacologically and genetically induced pathology also supports the suggestion that phospholipids play an important role in the formation and mineralization of dental tissues.

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Section: (I) Concentration and Distribution Of Lipids In Enamel And Dsupporting

confidence: 55%

“…The data obtained with bovine fetal tissue are very similar (Shapiro et al, 1966;Prout et al, 1973;Ellingson et al, 1977).…”

Section: (I) Concentration and Distribution Of Lipids In Enamel And Dmentioning

confidence: 56%

Phospholipids in Amelogenesis and Dentinogenesis

Goldberg¹,

Septier²

2002

Critical Reviews in Oral Biology & Medicine

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“…The intensity of the labeling in the mineralizing areas appears increased under those conditions in which the mineral component is partly removed, either by etching with sodium alcoholate in the epoxy resins, or by the aqueous solution during the incubation of the samples embedded in hydrophilic resins. This suggests that, as indicated by chemical assay, a portion of the phospholipids is accessible only after removal of the mineral phase (Irving and Wuthier 1968;Prout et al 1973). However, the demineralization does not increase the labeling intensity of the fully calcified bone matrix, suggesting that the phospholipid concentration is greatly reduced in this region.…”

Section: Discussionmentioning

confidence: 83%

“…A possible role of phospholipids in the initial phases of mineral deposition (Shapiro et al 1966;Irving and Wuthier 1968;Prout et al 1973;Boskey et al 1988) is further suggested by these ultrastructural cytochemical observations, which can be considered as a useful method to further investigate the mechanism of the mineralization process and of its pathological alterations.…”

Section: Discussionmentioning

confidence: 98%

“…In fact, complete lipid extraction from mineralized tissues can be obtained only after demineralization, indicating that some lipids are closely related to the extracellular matrix and may play a role in mineral-phase formation and maintenance (Shapiro et al 1966;Irving and Wuthier 1968;Prout et al 1973). In particular, phospholipids have been found in calcifying tissues, both as proteolipid Ca-phosphate complexes in the extracellular matrix (Eisenberg et al 1970;Vogel and Boyan-Salyers 1976;Boskey and Posner 1977;Boyan et al 1989;Goldberg et al 1990), and as constituents of the matrix vesicles, which are sites of initial mineral deposition (Anderson 1969;Wuthier 1976;Bonucci 1981Bonucci , 1984.…”

Section: Introductionmentioning

confidence: 96%

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Influence of specimen preparation on the identification of phospholipids by the phospholipase A2-gold method in mineralizing cartilage and bone

Zini¹,

Sabatelli²,

Silvestrini

et al. 1996

Histochem Cell Biol

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The role of phospholipids in biological mineralization has been hypothesized but not fully elucidated. In order to identify phospholipids at the ultrastructural level in the mineralizing extracellular matrix, rat epiphyseal cartilage and metaphyseal bone have been labeled with the phospholipase A(2) (PLA(2))-gold method. The specificity and the efficiency of phospholipid detection have been evaluated by postembedding labeling of sections from epoxy- or hydrophilic resin-embedded samples, and by preembedding labeling of cryosectioned samples. The efficiency of the labeling was higher in cryosections than in hydrophilic resin-embedded specimens, while lower efficiency was found in epoxy resin-embedded samples. A 2- to 6-fold increase of the labeling density in calcified with respect to uncalcified areas of cartilage and bone has been found, depending on the specimen preparation used. The labeling intensity was significantly higher, at the periphery of the calcifying nodules in the epiphyseal cartilage matrix and in the calcifying osteoid, while the fully calcified bone matrix presented a weak labeling. Matrix vesicles, which are considered a possible source of extracellular phospholipids, appeared labeled in cryosections and in epoxy resin-embedded samples after a preincubation with PLA(2), which also increased the labeling of the intracellular membranes. The localization of phospholipids in the areas of initial mineralization suggests some hypotheses on the possible involvement of these molecules in the mineral phase deposition process.

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Biosynthesis and secretion of enamel proteins in the rat incisor

et al. 1989

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The synthesis and secretion of enamel proteins (EPs) in rat incisors was examined using cytochemical and biochemical methods. Radioautography after injection of 3H-methionine showed that ameloblasts in the presecretory, secretory, and maturation stages of amelogenesis actively synthesized and secreted proteins. Immunocytochemistry with an antibody to mouse amelogenins revealed the presence of EPs in the protein synthetic and secretory organelles of these cells at all three stages. Labeling was also found in elements of the endosomal/lysosomal compartment. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and silver staining of proteins extracted from enamel and enamel organ showed several protein bands. However, transfer to nitrocellulose paper and immunoblotting revealed that most of the proteins recognized by the antibody were situated between approximately 14 and 32 kDa. EPs were further characterized by using lectins to examine their carbohydrate content. Lectin-gold cytochemistry on sections showed the binding of wheat germ agglutinin and Helix pomatia lectin to secretory stage enamel. Lectin blotting indicated that the amelogenins were heterogeneously glycosylated and contained the sugars N-acetyl-glucosamine/N-acetyl-neuraminic acid and N-acetyl-D-galactosamine. Fluorography at 6 and 10 min and 1 h after injection of 35S-methionine revealed four labeled bands in the main amelogenin group near 22, 28, 30, and 32 kDa. A short-lived protein of approximately 58 kDa was also observed primarily in cells. The appearance of labeled proteins in enamel was paralleled by their disappearance from cells and the intensity of the radiolabeled protein bands, both, in enamel and in cells, decreased towards the maturation stage. These data are consistent with the concept that ameloblasts produce multiple amelogenins throughout amelogenesis.

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Lipid analysis of rat enamel and dentine

Cited by 66 publications

References 18 publications

Phospholipids in Amelogenesis and Dentinogenesis

Phospholipids in Amelogenesis and Dentinogenesis

Influence of specimen preparation on the identification of phospholipids by the phospholipase A2-gold method in mineralizing cartilage and bone

Biosynthesis and secretion of enamel proteins in the rat incisor

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