Premium
Long‐term intermittent shear deformation improves the quality of cartilaginous tissue formed in vitro
Author(s) -
Waldman Stephen D.,
Spiteri Caroline G.,
Grynpas Marc D.,
Pilliar Robert M.,
Kandel Rita A.
Publication year - 2003
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1016/s0736-0266(03)00009-3
Subject(s) - proteoglycan , cartilage , in vitro , biomedical engineering , shearing (physics) , chemistry , biophysics , shear force , chondrocyte , articular cartilage , materials science , anatomy , composite material , osteoarthritis , medicine , biochemistry , pathology , biology , alternative medicine
The formation of cartilaginous tissue in vitro is a promising alternative to repair damaged articular cartilage. However, recent attempts to tissue‐engineer articular cartilage that has similar properties to the native tissue have proven to be difficult. The in vitro‐formed cartilaginous tissue typically has a similar proteoglycan content to native cartilage, but has a reduced collagen content and only a fraction of the mechanical properties. In this study, we investigated whether the intermittent application of cyclic shearing forces during tissue formation would improve the tissue quality. Chondrocyte cultures were stimulated at a 2% shear strain amplitude at a frequency of 1 Hz for 400 cycles every 2nd day. At one week, both collagen and proteoglycan synthesis increased (23 ± 6% and 20 ± 6%, respectively) over the unstimulated, static controls. At four weeks, an increased amount of tissue formed ( stimulated : 1.85 ± 0.08, unstimulated : 1.58 ± 0.07 mg dry wt.). This tissue contained approximately 40% more collagen ( stimulated : 511 ± 23, unstimulated : 367 ± 24 μg/construct) and 35% more proteoglycans ( stimulated : 376 ± 21, unstimulated : 279 ± 26 μg/construct). Tissues that formed in the presence of shearing forces also displayed a 3‐fold increase in compressive load‐bearing capacity ( stimulated : 16 ± 5, unstimulated : 5 ± 1 kPa max. equilibrium stress) and a 6‐fold increase in stiffness ( stimulated : 112 ± 36, unstimulated : 20 ± 6 kPa max. equilibrium modulus) compared to the static controls. These results demonstrate that intermittent application of dynamic shearing forces over a four‐week period improves the quality of cartilaginous tissue formed in vitro. Interestingly, low amplitudes of shear stimulation for short periods of time (6 min of stimulation applied every 2nd day) produced these changes. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved.