Early changes in morphology, bone mineral density and matrix composition of vertebrae lead to disc degeneration in aged collagen IX -/- mice

Kamper, Matthias; Hamann, Nina; Prein, Carina; Clausen-Schaumann, Hauke; Farkas, Zsuzsanna; Aszodi, Attila; Niehoff, Anja; Paulsson, Mats und Zaucke, Frank (2016): Early changes in morphology, bone mineral density and matrix composition of vertebrae lead to disc degeneration in aged collagen IX -/- mice. In: Matrix Biology, Bd. 49: S. 132-143

Abstract

Collagen IX (Col IX) is an important component of the cartilage extracellular matrix and has been associated with degenerative cartilage disorders and chondrodysplasias in humans. Further, polymorphisms in Col IX are known risk factors for the development of early intervertebral disc (IVD) degeneration. To understand the role of Col IX in the pathogenesis of IVD disorders, the spine of newborn and older Col IX deficient mice was systematically analyzed and compared to C57BL/6N controls. Morphology and bone parameters of the spine from newborn, 6 and 10 months old animals were investigated using mu CT measurements. Histological staining was used to evaluate tissue structure and degree of degeneration. Localization and expression of extracellular matrix proteins was analyzed in depth by immunofluorescence staining, immunoblotting, RT-PCR and in situ hybridization. High resolution imaging and stiffness measurements were performed by atomic force microscopy (AFM). Vertebral bodies of newborn Col IX-deficient mice were smaller and showed an increased mineral density compared to wild type animals. At birth, lack of Col IX led to a disrupted cellular organization in the cartilaginous endplate and a smaller nucleus pulposus of the IVD. Expression levels and localization of other extracellular matrix proteins were strongly altered accompanied by a softening of cartilaginous tissues. In older animals, absence of Col IX caused earlier and more pronounced disc degeneration with annular fissures. The absence of Col IX induces early developmental, structural and biomechanical alterations in both vertebral body and intervertebral disc which eventually cause severe degenerative changes in the aging spine. (C) 2015 Elsevier B.V. All rights reserved.

• Dokumententyp: Zeitschriftenartikel
• Fakultätsübergreifende Einrichtungen: Center for NanoScience (CENS)
• Themengebiete: 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
• ISSN: 0945-053X
• Sprache: Englisch