Abstract
The notochord gives rise to spinal segments during development, and it becomes embedded within the nucleus pulposus of the intervertebral disc (IVD) during maturation. The disruption of the notochord band has been observed with IVD degeneration. Since the mechanical competence of the IVD relies on its structural constituents, defining the structure of the notochord during aging is critical for investigations relating to IVD function and homeostasis. The assessment and imaging of the notochord has classically relied on histological techniques, which introduces sectioning artifacts during preparation and spatial biases. Magnetic resonance imaging (MRI) does not offer sufficient resolution to discriminate the notochord from the surrounding the nucleus pulposus, especially in murine models. Current X-ray based computed tomography systems provide imaging resolutions down to the single- and sub- micron scales, and when coupled with contrast-enhancing agents, enable the high-resolution three-dimensional imaging of relatively small features. Utilizing phosphomolybdic acid to preferentially bind to collagen cationic domains, we describe the structure of the notochord remnants with aging in the lumbar IVDs of BALB/c mice. These results provide a highly quantitative and sensitive approach to monitoring the IVD during postnatal development.
Highlights
Structural studies of the intervertebral disc (IVD) typically involve histological techniques or electron microscopy[10,11]
Examination of the correlations in the individual Annulus fibrosus (AF), nucleus pulposus (NP), and NC compartments show that while the 1μm- and 6 μm- micro-computed tomography (microCT) data were highly correlated for the AF (Pearson’s correlation, p < 0.001, r2 = 0.87) and the NP compartments (Pearson’s correlation, p < 0.01, r2 = 0.89), the NC compartment correlation resulted in significant, but less correlated values (Pearson’s correlation, p < 0.05, r2 = 0.67), suggesting that there are trade-offs in accuracy in the 6 μm-resolution scans
Annulus fibrosus (AF), the inner nucleus pulposus (NP), and the notochord (NC) percentages are normalized to the respective discs and averaged within the age group
Summary
Structural studies of the IVD typically involve histological techniques or electron microscopy[10,11] Histological approaches such as whole-mount offer insightful information regarding the spatial postnatal development at the macro-level, and sectioning allow the identification of molecular expression with tissue-specific context[12,13,14]. Confocal and electron microscopy provide detailed information within a very localized area[11] These approaches do not allow a full three-dimensional assessment as they require the destructive preparation of the sample. We report quantitative three-dimensional metrics: the notochord surface area to volume ratio (S.a/V), which defines the structure of the notochord, and the notochord volume These data provide important normative data for the three-dimensional notochord structure with aging, and it will be valuable in future studies of intervertebral disc disease and degeneration
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
