Leprévost Amandine, Azaïs Thierry, Trichet Michael, Sire Jean-Yves
Sorbonne Universités, UPMC Univ Paris 06, Institut de Biologie Paris-Seine, CNRS, UMR7138-Department Evolution Paris Seine, Equipe 'Evolution et Développement du Squelette', Paris, France.
Sorbonne Universités, UPMC Univ Paris 06, CNRS, Collège de France, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 11 place Marcelin Berthelot, Paris, F-75005, France.
J Morphol. 2017 Nov;278(11):1586-1597. doi: 10.1002/jmor.20734. Epub 2017 Jul 25.
In a study aiming to improve knowledge on the mineralization of the axial skeleton in reared Siberian sturgeon (Acipenser baerii Brandt, 1869), we discovered a new mineralized tissue within the notochord. To our knowledge, such a structure has never been reported in any vertebrate species with the exception of the pathological mineralization of the notochord remains in degenerative intervertebral disks of mammals. Here, we describe this enigmatic tissue using X-ray microtomography, histological analyses and solid state NMR-spectroscopy. We also performed a 1-year monitoring of the mineral content (MC) of the notochord in relation with seasonal variations of temperature. In all specimens studied from 2-year-old juveniles onwards, this mineralized structure was found within a particular region of the notochord called funiculus. This feature first appears in the abdominal region then extends posteriorly with ageing, while the notochord MC also increases. The mineral phase is mainly composed of amorphous calcium phosphate, a small amount of which changes into hydroxyapatite with ageing. The putative role of this structure is discussed as either a store of minerals available for the phosphocalcic metabolism, or a mechanical support in a species with a poorly mineralized axial skeleton. A pathological feature putatively related to rearing conditions is also discussed.
在一项旨在增进对养殖西伯利亚鲟（Acipenser baerii Brandt，1869）中轴骨骼矿化认识的研究中，我们在脊索内发现了一种新的矿化组织。据我们所知，除了哺乳动物退变椎间盘内脊索的病理性矿化外，这种结构从未在任何脊椎动物物种中被报道过。在此，我们使用X射线显微断层扫描、组织学分析和固态核磁共振光谱对这种神秘组织进行了描述。我们还对脊索的矿物质含量（MC）与温度的季节性变化关系进行了为期1年的监测。在所有从2岁幼鱼开始研究的标本中，这种矿化结构存在于脊索的一个特定区域，称为索状部。这一特征首先出现在腹部区域，然后随着年龄增长向后延伸，同时脊索的MC也增加。矿化相主要由无定形磷酸钙组成，其中少量随着年龄增长转变为羟基磷灰石。讨论了这种结构的假定作用，要么是作为磷钙代谢可用矿物质的储存库，要么是在中轴骨骼矿化程度较低的物种中提供机械支撑。还讨论了一种可能与养殖条件相关的病理特征。
