Abstract
Growth plates of rachitic, pair-fed control, normal and Vitamin D2- and phosphate-treated rachitic rats were studied with the electron microscope. Mitochondrial granule distribution was modified in the rachitic tissue; granules were noted only in a few cells adjacent to the zone of provisional calcification. Control rats demonstrated a gradient of granules throughout the growth plate. Supplementation of the rachitogenic diet with either phosphate, Vitamin D2, or both was able to re-establish the granule density and distribution found in control animals. It is suggested that one specific modification induced in mitochondria of chondrocytes by a low phosphate, Vitamin D2-deficient diet is the reduced ability to form mineral-containing mitochondrial granules.
Abstract
Des métaphyses de rats rachitiques, alimentés par paires avec des rats témoins, normaux et traités à la vitamine D2 et des phosphates, ont été étudiées au microscope électronique. La répartition des granules mitochondriales est modifiée dans le tissu rachitique: des granules ne sont visibles que dans quelques cellules voisines de la région en voie de calcification. Les rats témoins présentent une répartition, en gradient, à travers toute la métaphyse. L'adjonction à ce régime cariogène de phosphate ou vitamine D2 ou les deux à la fois, permet de rétablir la répartition normale des granules, visible chez les témoins. Il semble qu'une des modifications spécifiques, induites dans les mitochondries des chondrocytes, par un régime pauvre en phosphate et déficient en vitamine D2, est la diminution de la formation de granules mitochondriales, contenant des produits inorganiques.
Zusammenfassung
Wachstumszonen von rachitischen Ratten werden unter dem Elektronenmikroskop verglichen mit denjenigen von 3 Kontrollgruppen (normale Diät rachitogene Diät mit Vitamin D2 und Phosphatzusätzen und eingeschränkte Menge normaler Diät). Die Verteilung der Granula in den Mitochondrien war im rachitischen Gewebe verändert; Granula wurden nur in einigen Zellen festgestellt, welche an die Zone der provisorischen Kalzifikation angrenzten. Kontrollratten zeigten einen Gradienten von Granula auf der ganzen Wachstumsplatte. Ergänzung der rachitogenen Diät durch Phosphat, Vitamin D2 oder beide bewirkte die Wiederherstellung der Granula-Dichte und-Verteilung, welche die Kontrolltiere aufwiesen. Es wird vorgeschlagen, daß die verminderte Fähigkeit, mineralhaltige Mitochondrien-Granula zu bilden, eine spezifische Veränderung ist, welche in den Mitochondrien von Chondrocyten durch eine phosphatarme, Vitamin D2-defizitäre Diät herbeigeführt wird.
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This work was supported in part by grants from the National Institutes of Health. Numbers AM-09632, DE-224-01 and FR 5577-05.
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Matthews, J.L., Martin, J.H., Sampson, H.W. et al. Mitochondrial granules in the normal and rachitic rat epiphysis. Calc. Tis Res. 5, 91–99 (1970). https://doi.org/10.1007/BF02017539
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DOI: https://doi.org/10.1007/BF02017539