MESENCHYMAL STEM CELLS AND CHONDROCYTE CO-CULTURE PROMOTES CHONDROCYTE MATRIX PRODUCTION IN NORMOXIC CONDITIONS
Articular cartilage is a tissue that shows no capacity for effective spontaneous regeneration. Tissue engineering, as a new important field of regenerative medicine, emerges as potential effective solution for treatment of articular cartilage injuries and defects. The aim of this study was to evaluate the chondrocyte preference of oxygen level for three-dimensional (3D) in vitrochondrogenesis and to test whether the presence of mesenchymal stem cells (MSCs) would influence the preference of oxygen level. In the experiment, we set up two different cell cultures: only chondrocytes and combination of chondrocytes and MSCs in 2:1 ratio. Cells were grown in a chondrogenic medium, incorporated in a peptide hydrogel RADA, in either normoxic (20% O2) or hypoxic (5% O2) conditions. After 19 days, expression levels of two cartilage marker genes, SOX9and ACAN, were evaluated by real-time quantitative PCR. In conclusion, hypoxia enhanced chondrogenesis significantly only in the case of chondrocytes, while co-culturing with MSCs slightly improved differentiation in normoxic conditions.