Fig. 2

Effect of culture conditions on the mRNA relative expression in cartilage engineered substitutes. Synovial fluid derived mesenchymal stem cells (sf-MSCs) were cultured in collagen sponges in normoxia (21% O2—gray histogram) or in hypoxia (5% O2—white histogram) during 28 days. Sponges were treated from day 3 with ITS 1% as control condition or with TGF-β1 (10 ng/mL) alone or in combination with BMP-2 (100 ng/mL) and BMP-2 (100 ng/mL) alone. We investigated relative mRNA expression by using real-time polymerase chain reaction of chondrogenic (COMP, ACAN, SOX9, COL2A1, COL2B), fibrotic (VCAN, COL1A1) and osteogenic markers (BGLAP and RUNX2). All results were normalized to RPS29 mRNA expression. Each histogram represents three independent experiments performed in triplicate. Data are presented as mean ± standard error of the mean. Statistical analysis was performed initially with a one-way ANOVA with a Dunnett’s post hoc test versus their internal control ITS for each condition (normoxia separated from hypoxia) followed by a two-way ANOVA with a Bonferroni’s post hoc test on all the values the interaction of hypoxia. Asterisks represent significant difference versus the control condition (ITS 1%) *p < 0.05; **p < 0.01; ***p < 0.001 in each condition. Hash sign represents significant difference of growth factor condition in normoxia versus hypoxia taken into account both conditions #p < 0.05; ##p < 0.01; ###p < 0.001 (significant interaction of hypoxia)