Experimental Measurement of Evolving Articular Cartilage Properties During In Vitro Growth

The aims of these studies were to conduct in vitro growth protocols and measure articular cartilage (AC) structure-function relations. Newborn bovine patellofemoral AC explants were tested to determine mechanical (e.g. confined compression, unconfined compression, uniaxial tension, and torsional shear) and biochemical (i.e. contents of water, glycosaminoglycans, collagen type II, and collagen-specific pyridinoline crosslinks) properties before and after in vitro growth. In vitro growth protocols included mechanically unstimulated growth in medium supplemented with fetal bovine serum (FBS), insulin growth factor (IGF), and transforming growth factor beta 1 (TGF-B1) and mechanically stimulated growth with steady-state permeation, static bending, and dynamic compression.

Typically, mechanical and biochemical properties evolved during, and were differentially regulated by, the different in vitro growth protocols. Statistical analyses detected both significant changes in properties and significant structure-function relations (i.e. the relations between mechanical and biochemical properties). These results were used to identify parameters in our macro- and micro- scale models of AC tissue biomechanics, with emphasis on growth and remodeling.

Publications

  • Balcom NT, Berg-Johansen B, Dills KJ, Van Donk JR, Williams GM, Chen AC, Hazelwood SJ, Sah RL, Klisch SM. In vitro articular cartilage growth with sequential application of IGF-1 and TGF-b1 enhances volumetric growth and maintains compressive properties. Journal of Biomechanical Engineering, 134:031001, 2012.
  • Williams GM, Dills KJ, Flores CR, Stender ME, Stewart KM, Nelson LM, Chen AC, Masuda K, Hazelwood SJ, Klisch SM, Sah RL. Differential regulation of immature articular cartilage compressive moduli and Poisson’s ratios by in vitro stimulation with IGF-1 and TGF-β1. Journal of Biomechanics, 43: 2501-2507, 2010.ABSTRACT PDF
  • Ficklin T, Thomas G, Barthel JC, Thonar EJ, Masuda K, Asanbaeva A, Chen AC, Sah RL, Davol A, Klisch SM. Articular cartilage mechanical and biochemical property relations before and after in vitro growth. Journal of Biomechanics, 40:3607-3614, 2007.ABSTRACT PDF

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