Transient hypoxia improves matrix properties in tissue engineered cartilage
Resource
J. Orthop. Res., 31(4), 544-553
Journal
Journal of Orthopaedic Research
Pages
544-553
Date Issued
2013
Date
2013
Author(s)
Yodmuang, Supansa
Gadjanski, Ivana
Chao, Pen-hsiu Grace
Vunjak-Novakovic, Gordana
Abstract
Adult articular cartilage is a hypoxic tissue, with oxygen tension ranging from <10% at the cartilage surface to <1% in the deepest layers. In addition to spatial gradients, cartilage development is also associated with temporal changes in oxygen tension. However, a vast majority of cartilage tissue engineering protocols involves cultivation of chondrocytes or their progenitors under ambient oxygen concentration (21% O2), that is, significantly above physiological levels in either developing or adult cartilage. Our study was designed to test the hypothesis that transient hypoxia followed by normoxic conditions results in improved quality of engineered cartilaginous ECM. To this end, we systematically compared the effects of normoxia (21% O2 for 28 days), hypoxia (5% O2 for 28 days) and transient hypoxiareoxygenation (5% O2 for 7 days and 21% O2 for 21 days) on the matrix composition and expression of the chondrogenic genes in cartilage constructs engineered in vitro. We demonstrated that reoxygenation had the most effect on the expression of cartilaginous genes including COL2A1, ACAN, and SOX9 and increased tissue concentrations of amounts of glycosaminoglycans and type II collagen. The equilibrium Young's moduli of tissues grown under transient hypoxia (510.01 +/- 28.15kPa) and under normoxic conditions (417.60 +/- 68.46kPa) were significantly higher than those measured under hypoxic conditions (279.61 +/- 20.52kPa). These data suggest that the cultivation protocols utilizing transient hypoxia with reoxygenation have high potential for efficient cartilage tissue engineering, but need further optimization in order to achieve higher mechanical functionality of engineered constructs. (c) 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31: 544553, 2013
Subjects
tissue engineering
cartilage
hypoxia
hydrogel
extracellular matrix