Dynamic compression combined with SOX-9 overexpression in rabbit adipose-derived mesenchymal stem cells cultured in a three-dimensional gradual porous PLGA composite scaffold upregulates HIF-1 expression

There is considerable interest in how the fate of adipose-derived stem cells is determined. Physical stimuli play a crucial role in skeletogenesis and in cartilage repair and regeneration. In the present study, we investigated the comparative and interactive effects of dynamic compression and SRY-related high-mobility group box gene-9 (SOX-9) on chondrogenesis of rabbit adipose-derived stem cells in three-dimensional gradual porous PLGA (polylactic-co-glycolic acid) composite scaffolds. Articular cartilage is stratified into zones delineated by characteristic changes in cellular, matrix, and nutritive components. As a consequence, biochemical and biomechanical properties vary greatly between the different zones, giving the tissue its unique structure and, thus, the ability to cope with extreme loading. The effects on development of the cartilage were examined using a combination of computational modeling to predict alterations in biophysical stimuli, detailed morphometric analysis of 3D digital representations. In addition, early chondrogenic differentiation was assessed via real-time PCR of mRNA expression levels for bone- and cartilage-specific gene markers. Our findings define the important role of dynamic compression combined with SOX-9 overexpression during in vitro generation of tissue-engineering cartilage and suggest that a 3D gradual porous PLGA composite scaffold may benefit articular cartilage tissue engineering in cartilage regeneration for better force distribution. (c) 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 103A: 3886-3895, 2015.