Table 4.
Macro-, micro-, nano- and compositional-level properties of rat cortical and trabecular bone found by this study.
| variable | modality | units | cortical bone | cancellous bone | p value |
|---|---|---|---|---|---|
| bone tissue density | pycnometry | g cm−3 | 2.17 (0.017) | 2.16 (0.07) | 0.78 |
| mineral content | gravimetry | % | 66.63 (7.64) | 68.90 (9.94) | 0.42 |
| matrix content | gravimetry | % | 28.97 (7.64) | 26.55 (9.93) | 0.42 |
| stiffness | mechanical testing | N mm−1 | 7199 (270) | 719 (68) | <0.001 |
| yield load | mechanical testing | N | 737 (110) | 43 (23) | <0.001 |
| bone volume fraction | μCT imaging | mm3 mm−3 | 0.59 (0.03) | 0.37 (0.04) | <0.001 |
| bone-surface-to-volume ratio | μCT imaging | mm2 mm−3 | 3.84 (0.19) | 14.44 (2.91) | <0.001 |
| modulus of elasticity (E) | mechanical testing | GPa | 8.50 (2.86) | 2.47 (1.68) | <0.001 |
| yield strength (YS) | mechanical testing | GPa | 0.13 (0.02) | 0.03 (0.01) | <0.001 |
| tissue modulus | nano-indentation | GPa | 18.98 (5.73) | 18.27 (3.77) | 0.46 |
| hardness | nano-indentation | GPa | 0.74 (0.25) | 0.73 (0.21) | 0.72 |
| total protein | amino acid analysis | % | 11.80 (4.11) | 11.57 (3.43) | 0.90 |
| total collagen | amino acid analysis | % | 10.50 (3.84) | 9.58 (3.27) | 0.59 |
| collagen content in protein | amino acid analysis | % | 88.57 (2.04) | 82.04 (3.20) | <0.001 |
| PO4 (non-apatitic) | FT-IR | % | 10.42 (1.95) | 9.52 (1.30) | 0.25 |
| HPO4 | FT-IR | % | 30.60 (4.74) | 28.91 (4.80) | 0.44 |
| CO3 | FT-IR | % | 3.63 (1.48) | 2.56 (1.12) | 0.11 |
| C/P | FT-IR | — | 0.056 (0.002) | 0.058 (0.003) | 0.09 |
| protein-to-mineral ratio | FT-IR | — | 0.77 (0.09) | 0.70 (0.05) | 0.89 |
| Ca content | chemical analysis | µg mg−1 of bone | 261.19 (100.40) | 298.61 (20.135) | 0.29 |
| PO4 content | chemical analysis | µg mg−1 of bone | 18.74 (5.46) | 19.26 (4.23) | 0.76 |