Journal Article

Simulated-Physiological Loading Conditions Preserve Biological and Mechanical Properties of Caprine Lumbar Intervertebral Discs in Ex Vivo Culture

Mullender, Margriet G., Paul, Cornelis P. L., van der Veen, Albert J., Zuiderbaan, Hendrik A., van Royen, Barend J., Zandieh Doulabi, Behrouz, van de Ven, Peter M., Helder, Marco N., Smit, Theo H.

2012

Overview

Low-back pain (LBP) is a common medical complaint and associated with high societal costs. Degeneration of the intervertebral disc (IVD) is assumed to be an important causal factor of LBP. IVDs are continuously mechanically loaded and both positive and negative effects have been attributed to different loading conditions.In order to study mechanical loading effects, degeneration-associated processes and/or potential regenerative therapies in IVDs, it is imperative to maintain the IVDs' structural integrity. While in vivo models provide comprehensive insight in IVD biology, an accompanying organ culture model can focus on a single factor, such as loading and may serve as a prescreening model to reduce life animal testing. In the current study we examined the feasibility of organ culture of caprine lumbar discs, with the hypothesis that a simulated-physiological load will optimally preserve IVD properties.Lumbar caprine IVDs (n = 175) were cultured in a bioreactor up to 21 days either without load, low dynamic load (LDL), or with simulated-physiological load (SPL). IVD stiffness was calculated from measurements of IVD loading and displacement. IVD nucleus, inner- and outer annulus were assessed for cell viability, cell density and gene expression. The extracellular matrix (ECM) was analyzed for water, glycosaminoglycan and total collagen content.IVD biomechanical properties did not change significantly with loading conditions. With SPL, cell viability, cell density and gene expression were preserved up to 21 days. Both unloaded and LDL resulted in decreased cell viability, cell density and significant changes in gene expression, yet no differences in ECM content were observed in any group.In conclusion, simulated-physiological loading preserved the native properties of caprine IVDs during a 21-day culture period. The characterization of caprine IVD response to culture in the LDCS under SPL conditions paves the way for controlled analysis of degeneration- and regeneration-associated processes in the future.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Analysis / Animal research / Animals / Apoptosis / Back pain / Biological properties / Biology / Biomechanical Phenomena / Biomechanics / Bioreactors / Bone surgery / Cell culture / Cell density / Collagen / Computer simulation / Degeneration / Density / Disease Models, Animal / DNA Primers - genetics / DNA, Complementary - genetics / Dynamic loads / Extracellular matrix / Extracellular Matrix - metabolism / Feasibility studies / Gene expression / Gene Expression Profiling / Glycosaminoglycans / Goats / Histological Techniques / In vivo methods and tests / Intervertebral Disc - physiology / Intervertebral discs / Joint surgery / Linear Models / Low back pain / Low Back Pain - etiology / Low Back Pain - physiopathology / Low density lipoprotein / Low density lipoproteins / Lumbosacral Region / Mechanical loading / Mechanical properties / Nuclei / Nuclei (cytology) / Organ culture / Orthopedics / Pain / Physiological aspects / Physiology / Pressure / Regeneration / Reverse Transcriptase Polymerase Chain Reaction / Social aspects / Stiffness / Structural integrity / Studies / Tissue Culture Techniques - methods / Tissue engineering / Weight-Bearing