Figure 5
Effect of culture conditions on the mRNA steady-state levels of specific markers in mature and hypertrophic chondrocytes and osteoblasts.
Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) were cultured in collagen sponges at 21% O2 for 14 days, in incomplete chondrogenic medium in the absence (control) or presence of 50 ng/ml of BMP-2 and 10 ng/ml of TGF-β1. Undifferentiated hUCB-MSCs were also cultured as monolayers and used as a control before differentiation (day 0, D0). mRNA extracts obtained from human articular chondrocytes (HACs) released from cartilage after overnight enzymatic digestion were used as controls. (A) Relative mRNA expression of chondrogenic markers. (B) Relative mRNA expression of hypertrophic chondrocyte and osteoblast markers. Bone: mRNA extracted from osteoblast cultures at passage 3 and obtained from human femoral head of osteoarthritis patients. (C) COL2A1:COL1A1 mRNA ratio. All results were normalized to RPL13a mRNA expression, compared with undifferentiated hUCB-MSCs cultured in monolayer, and presented as the relative expression of each gene. Box plots represent six independent experiments performed in triplicate. Statistically significant differences among hUCB-MSCs in monolayer and untreated or treated cells in sponges were determined using the Kruskal-Wallis test (*p < 0.05, **p < 0.01, ***p < 0.001).
