Figure 5. A. Tenocyte related gene expression by hTSCs under hypoxic and normaxic culture conditions.

Total RNA extracted from hTSCs grown under hypoxic or normaxic conditions was used to synthesize cDNA, which was used as a template in qRT-PCR using primers specific to Collagen-1 and Tenascin C. GAPDH was used as an internal control. Y- axis represents relative gene expression when compared to GAPDH expression levels. Ct values were normalized against hTSCs cultured under 20% O₂. At both oxygen conditions (5% and 20% O₂), there was no significant difference in the expression of collagen type I, but the expression of tenascin C in the hypoxic group was significantly higher than in the normaxic group (*P<0.05). B. Non-tenocyte related gene expression by hTSCs under the above two oxygen conditions. Total RNA extracted from hTSCs grown under hypoxic or normaxic conditions was used to synthesize cDNA, which was used as a template in qRT-PCR using primers specific to PPARγ, Sox-9 and Runx-2. GAPDH was used as an internal control. Y- axis represents relative gene expression when compared to GAPDH expression. Ct values were normalized against hTSCs cultured under 20% O₂. The cellular expression of PPARγ, a marker for adipogenesis, was not significantly different in 5 and 20% O₂ conditions. However, Sox-9 and Runx-2 (markers for chondrogenesis and osteogenesis, respectively) were expressed at significantly lower levels when hTSCs were cultured at 5% O₂ condition in comparison to 20% O₂ (*P<0.05, respective to hTSCs that were under normaxic conditions).