Figure 2

Quantification of gene expression with quantitative polymerase chain reaction. Gene expression levels of (A) COL1A1, (B) COL2A1, (C) COL3A1, and (D) COL10A1 were determined in mono-, co-, and tri-cultures by using standard curves. Bone marrow-derived stem cells (BMSCs) (white bars), mixed cultures (BMSCs and chondrocytes in a ratio of 1:1, light grey bars), or chondrocytes (dark grey bars) were kept as monocultures (F, bars with pattern) or as co- and tri-cultures with osteoarthritis cartilage explants (FC, solid bars) in chondrogenic medium. Owing to high inter-experimental variability, we have calculated the raw data as percentage of highest cDNA copy number per individual experiment. Results are presented as mean with standard deviation. *P <0.05; **P <0.01; ***P <0.001. N = 6. Ch, chondrocytes.