Novel ex-vivo mechanobiological intervertebral disc culture system

JOURNAL OF BIOMECHANICS

卷:45

Article

Hartman, Robert A.^1,2  Bell, Kevin M.^2,3  Debski, Richard E.^2,4  Kang, James D.³  Sowa, Gwendolyn A.^1,2,3 

[1] Univ Pittsburgh, Dept Phys Med & Rehabil, Pittsburgh, PA 15213 USA

[2] Univ Pittsburgh, Dept Bioengn, Ctr Bioengn 360B, Pittsburgh, PA 15219 USA

[3] Univ Pittsburgh, Ferguson Lab Orthopaed Res, Dept Orthopaed Surg, Pittsburgh, PA 15261 USA

[4] Univ Pittsburgh, Dept Bioengn, Musculoskeletal Res Ctr, Ctr Bioengn 405, Pittsburgh, PA 15219 USA

关键词: Mechanobiology;    Functional spinal unit;    Organ culture;    Intervertebral disc;    Axial compression;   

DOI  :  10.1016/j.jbiomech.2011.10.036

来源: Elsevier

【 摘 要 】

Intervertebral disc degeneration, a leading cause of low back pain, poses a significant socioeconomic burden with a broad array of costly treatment options. Mechanical loading is important in disease progression and treatment. Connecting mechanics and biology is critical for determining how loading parameters affect cellular response and matrix homeostasis. A novel ex-vivo experimental platform was developed to facilitate in-situ loading of rabbit functional spinal units (FSUs) with relevant biological outcome measures. The system was designed for motion outside of an incubator and validated for rigid fixation and physiologic environmental conditions. Specimen motion relative to novel fixtures was assessed using a digitizer; fixture stiffness exceeded specimen stiffness by an order of magnitude. Intradiscal pressure (IDP), measured using a fiber-optic pressure transducer, confirmed rigidity and compressive force selection. Surrounding media was controlled at 37 degrees C, 5% O-2/CO2 using a closed flow loop with an hypoxic incubator and was validated with probes in the specimen chamber. FSUs were subjected to cyclic compression (20 cycles) and fourhour creep at 1.0 MPa. Disc tissue was analyzed for cell viability using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (Ml]'), which showed high viability ( > 90%) regardless of loading. Conditioned media was assayed for type-II collagen degradation fragments (CTX-II) and an aggrecan epitope (CS-846) associated with new aggrecan synthesis. CTX-II concentrations were not associated with loading, but CS-846 concentrations appeared to be increased with loading. Preservation of the full FSU allows physiologic load transmission and future multi-axis motion and identification of load-responsive proteins, thereby forming a new niche in intervertebral disc organ culture. (C) 2011 Elsevier Ltd. All rights reserved.

【 授权许可】

Free