Figures & data
Table 1. The 4 experimental conditions used
Figure 1. A. The chamber was fixed to the brackets by 4 hook-pins. The cell-seeded collagen gel was placed in the scaffold chamber. The media chamber was filled with serum-free medium with or without growth factor. B. Mechanical loading system. Dynamic compression loading was applied to the cell-seeded scaffold in the chamber.
Table 2. Primer sequences and product sizes in real-time PCR.
Figure 2. Effects of monolayer culture and repeated passage on aggrecan, collagen II, and collagen I gene expression of chondrocytes (relative to GAPDH gene expression). The monolayer-expanded chondrocytes were rapidly and significantly dedifferentiated from NCs to P0 cells for both aggrecan (panel A) and collagen II (panel B). The chondrocytic phenotypes were attenuated immediately in the P0 cells, with mRNA expression becoming progressively reduced with passage. Results are expressed as mean (95% confidence limit); n = 7. Comparison of mean values was performed by one-factor ANOVA analysis.P0: passage 0; NCs: non-culture chondrocytes. a p < 0.05, b p < 0.01, c p < 0.001, d p < 0.0001 vs. control (NCs).
Figure 3. Effects of 3-dimensional (3D) culture for 0–5 weeks on aggrecan, collagen II, and collagen I gene expression of NCs (relative to GAPDH gene expression). Expression of all 3 genes was downregulated during weeks 2–5. Results are expressed as mean (95% confidence limit); n = 5. Comparison of mean values was performed by one-factor ANOVA analysis. NCs: non-culture chondrocytes. a p < 0.05, d p < 0.0001.
Figure 4. Effects of 3D collagen gel culture. Histological appearance of cells at: week 0 (A), week 1 (B), week 2 (C), week 3 (D), week 4 (E), and week 5 (F). Representative sections were stained with toluidine blue. Scale bars: 10 µm.
Figure 5. Effects of dynamic compressive loading in serum-free medium on aggrecan, collagen II, and collagen I gene expression of chondrocytes in 3D scaffold (relative to GAPDH gene expression). Of the 4 different durations of loading, 60 min/day gave the greatest effect on aggrecan and collagen II gene expression. Results are expressed as mean (95% confidence limit); n = 5. Comparison of mean values was performed by one-factor ANOVA analysis. a p < 0.05, b p < 0.01.
Figure 6. Effects of dynamic compressive loading. Histological appearance of cells treated loading for 0 min/day (A), 10 min/day (B), 60min/day (C) and 120 min/day (D). Toluidine blue staining. The arrow in panel C points to a larger oval cell body. Scale bars: 10 µm.
Figure 7. Effects of dynamic compressive loading (for 60 min/day) in combination with growth factor (100 ng/mL bFGF or 100 ng/mL BMP-2) on aggrecan, collagen II, and collagen I gene expression of chondrocytes in 3D scaffold (relative to GAPDH gene expression). These growth factors did not have a synergistic effect under dynamic compressive loading. Results are expressed as mean (95% confidence limit); n = 7. Comparison of mean values was performed by one-factor ANOVA analysis. MS: mechanical stress; GF: growth factor. a p < 0.05, b p < 0.01, c p < 0.001.
Figure 8. Effects of dynamic compressive loading in combination with growth factor. Histological appearance of cells treated with: A. bFGF but no mechanical stress, B. BMP-2 but no mechanical stress, (C) bFGF and mechanical stress, and (D) BMP-2 and mechanical stress. Toluidine blue staining. The oval cell body and the ECM area in the “stress control” (growth factor but no mechanical stress, corresponding to panels A and B) were generally larger than in each study group (corresponding to panels C and D). Scale bars: 10 µm.
