title: Morphological assessment of bone mineralization in tibial metaphyses of ascorbic acid-deficient ODS rats.
abstract: Osteogenic disorder shionogi (ODS) rats carry a hereditary defect in ascorbic acid synthesis, mimicking human scurvy when fed with an ascorbic acid-deficient (aa-def) diet. As aa-def ODS rats were shown to feature disordered bone formation, we have examined the bone mineralization in this rat model. A fibrous tissue layer surrounding the trabeculae of tibial metaphyses was found in aa-def ODS rats, and this layer showed intense alkaline phosphatase activity and proliferating cell nuclear antigen-immunopositivity. Many osteoblasts detached from the bone surfaces and were characterized by round-shaped rough endoplasmic reticulum (rER), suggesting accumulation of malformed collagen inside the rER. Accordingly, fine, fragile fibrillar collagenous structures without evident striation were found in aa-def bones, which may result from misassembling of the triple helices of collagenous α-chains. Despite a marked reduction in bone formation, ascorbic acid deprivation seemed to have no effect on mineralization: while reduced in number, normal matrix vesicles and mineralized nodules could be seen in aa-def bones. Fine needle-like mineral crystals extended from these mineralized nodules, and were apparently bound to collagenous fibrillar structures. In summary, collagen mineralization seems unaffected by ascorbic acid deficiency in spite of the fine, fragile collagenous fibrils identified in the bones of our animal model.
authors: Department of Developmental Biology of Hard Tissue, Hokkaido University, Sapporo, Japan.
authors: Tomoka
authors: T
authors: Hasegawa
authors: Minqi
authors: M
authors: Li
authors: Kuniko
authors: K
authors: Hara
authors: Muneteru
authors: M
authors: Sasaki
authors: Chihiro
authors: C
authors: Tabata
authors: Paulo Henrique Luiz
authors: PH
authors: de Freitas
authors: Hiromi
authors: H
authors: Hongo
authors: Reiko
authors: R
authors: Suzuki
authors: Masatoshi
authors: M
authors: Kobayashi
authors: Kiichiro
authors: K
authors: Inoue
authors: Tsuneyuki
authors: T
authors: Yamamoto
authors: Noboru
authors: N
authors: Oohata
authors: Kimimitsu
authors: K
authors: Oda
authors: Yasuhiro
authors: Y
authors: Akiyama
authors: Norio
authors: N
authors: Amizuka
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000378:metabolism; D001206:Ascorbic Acid Deficiency / Q000473:pathology* / Q000503:physiopathology*; D001847:Bone Diseases / Q000473:pathology / Q000503:physiopathology; D002113:Calcification, Physiologic / Q000502:physiology*; D003094:Collagen / Q000378:metabolism / Q000648:ultrastructure; D004195:Disease Models, Animal; D006801:Humans; D008297:Male; D010006:Osteoblasts / Q000378:metabolism / Q000648:ultrastructure; D051381:Rats; D011922:Rats, Mutant Strains; D013977:Tibia / Q000033:anatomy & histology* / Q000502:physiology*
chemical_list: D003094:Collagen; D001205:Ascorbic Acid