Department of Orthopedic Surgery, VU University Medical Center, Amsterdam, the Netherlands; Amsterdam Movement Sciences, Academic Medical Center and VU University Medical Center, Amsterdam, the Netherlands; Aachen-Maastricht Institue for Biobased Materials, Faculty of Science and Engineering, Maastricht University, Maastricht, the Netherlands.
Department of Dental Materials Science, University of Amsterdam and VU University, Amsterdam, the Netherlands.
Biochem Biophys Res Commun. 2018 Sep 5;503(2):1168-1173. doi: 10.1016/j.bbrc.2018.06.136. Epub 2018 Jul 4.
The mammalian intervertebral disc (IVD) consists of a gel-like, disordered nucleus pulposus (NP) surrounded by a highly ordered collagen structure, the annulus fibrosus (AF). While this concentric array of lamellae has been amply studied, its physical origin is poorly understood. The notochord is a rod-like organ located in the mid-line of the growing embryo and plays an essential role in IVD development. The aim of this study was to elucidate the effect of notochord development on the collagen fiber arrangement evolution in the AF. To that end, we studied IVD development in mouse embryos and compared these observations to those from chicken embryos, which do not form the typical laminar structure around the NP. In mouse, cross-aligned collagen arrangement of the AF forms from the sclerotome upon bulging of the notochord to become NP. By contrast, the notochord in the chicken embryo swells substantially without the physical restrictions of the future vertebrae and thus do not bulge. From these observations, we conclude that physical and geometrical constrictions are essential for the formation of the highly structured AF.
哺乳动物的椎间盘（IVD）由凝胶状、无序的髓核（NP）组成，周围是高度有序的胶原结构，即纤维环（AF）。虽然这种同心层状结构已经得到了充分的研究，但它的物理起源却知之甚少。脊索是一种位于生长胚胎中线的杆状器官，在 IVD 发育中起着至关重要的作用。本研究旨在阐明脊索发育对 AF 中胶原纤维排列演变的影响。为此，我们研究了小鼠胚胎中的椎间盘发育，并将这些观察结果与鸡胚胎进行了比较，鸡胚胎的 NP 周围没有形成典型的层状结构。在小鼠中，随着脊索的膨胀，软骨膜中的交叉排列的胶原排列形成 NP 周围的 AF。相比之下，鸡胚胎的脊索在未来椎体的物理限制下会明显膨胀，因此不会膨胀。根据这些观察结果，我们得出结论，物理和几何限制对于形成高度结构化的 AF 是必不可少的。
