Table 2.
Mean of fold change and statistical differences of gene expression for soluble growth factors regulated by different oxygen tensions and culture methods. (a) Gene expression in chondrocytes; (b) gene expression in osteoblasts
| Growth factor gene | Mean Fold Change (Ratio to normal chondrocytes) | |||||
|---|---|---|---|---|---|---|
| Co‐culture | Hypoxia | Combined effect | ||||
| (a) | ||||||
| Aggrecan | 0.300 | ↓* | 0.274 | ↓* | 0.198 | ↓** |
| Col II | 0.480 | – | 0.619 | – | 0.341 | – |
| SOX9 | 1.227 | – | 2.178 | – | 1.784 | – |
| HIF‐1α | 0.784 | – | 2.077 | ↑* | 1.414 | – |
| VEGF‐A | 1.633 | – | 2.118 | ↑* | 4.457 | ↑* |
| VEGF‐B | 1.819 | ↑* | 2.374 | ↑** | 3.660 | ↑** |
| VE‐cadherin | 1.188 | – | 3.797 | ↑** | 2.664 | ↑** |
| PDGF | 0.471 | – | 0.512 | – | 0.362 | – |
| BMP‐2 | 1.367 | – | 1.768 | ↑* | 1.774 | ↑* |
| BMP‐4 | 1.109 | – | 0.504 | ↓* | 0.388 | – |
| BMP‐5 | 1.437 | – | 1.280 | – | 1.785 | – |
| BMP‐6 | 1.681 | – | – | – | 1.585 | – |
| BMP‐7 | – | – | – | – | – | – |
| IGF‐1 | 2.774 | – | 3.602 | ↑* | 2.291 | ↑** |
| FGF‐1 | 1.371 | – | 1.181 | – | 1.353 | – |
| FGF‐2 | 1.216 | – | 1.326 | – | 1.592 | – |
| TGF‐β1 | 1.167 | – | 1.173 | – | 1.037 | – |
| EGF | – | – | – | – | – | – |
| (b) | ||||||
| ALP | 0.604 | ↓* | 0.686 | ↓* | 0.371 | ↓* |
| RUNX2 | 0.498 | ↓** | 0.650 | – | 0.422 | ↓* |
| HIF‐1α | 0.674 | ↓* | 0.894 | – | 0.376 | ↓*** |
| VEGF‐A | 0.726 | – | 0.965 | – | 1.206 | – |
| VEGF‐B | 0.763 | – | 1.021 | – | 1.250 | – |
| VE‐cadherin | – | – | – | – | – | – |
| PDGF | 0.424 | ↓* | 0.333 | ↓* | 0.318 | – |
| BMP‐2 | 0.776 | ↓* | 1.786 | ↑* | 0.972 | – |
| BMP‐4 | 0.767 | – | 0.835 | – | 1.088 | – |
| BMP‐5 | 0.621 | – | 0.704 | – | 0.400 | ↓* |
| BMP‐6 | 0.425 | ↓* | 0.459 | ↓* | 0.209 | – |
| BMP‐7 | 0.720 | – | 1.158 | – | 0.903 | – |
| IGF‐1 | 0.876 | – | 1.285 | – | 1.170 | – |
| FGF‐1 | 0.519 | ↓* | 1.642 | – | 0.890 | – |
| FGF‐2 | 0.656 | – | 0.541 | – | 0.455 | – |
| TGF‐β1 | 0.960 | – | 0.992 | – | 0.873 | – |
| EGF | – | – | – | – | – | – |
The fold change values were calculated by OD method with Image‐Pro Plus 6.0 based on the semi‐quantitative PCR. ↓ or ↑ indicates trend of fold change.
*A significant difference with respect to normoxic monoculture group, P < 0.05; **P < 0.01; ***P < 0.001.
Co‐culture, normoxic co‐culture group with respect to normoxic monoculture group; Hypoxia, hypoxic monoculture group with respect to normoxic monoculture group; Combined effect, hypoxic co‐culture group with respect to normoxic monoculture group.