Table 1.
Biomechanical properties of femoral cortical bone assessed by 3-point bending
| Age | Parameter | MALES | FEMALES | |||||
|---|---|---|---|---|---|---|---|---|
| FMR1y/+ | FMR1y/− | FMR1y/−/FMR1y/+ (fold change) | FMR1+/+ | FMR1+/− | FMR1−/− | FMR1−/−/FMR1+/+ (fold change) | ||
| 2-month-old | Yield Force /N | 14.48 ± 1.94 | 15.58 ± 1.96 | 1.1 | 16.07 ± 3.45 | 17.38 ± 2.54 | 16.73 ± 3.58 | 1.0 |
| Ultimate Force /N | 19.83 ± 1.78 | 21.60 ± 1.12 | 1.1 | 19.89 ± 2.76 | 21.59 ± 1.94 | 21.25 ± 2.42 | 1.1 | |
| Stiffness /(N·mm−1) | 119.03 ± 14.52 | 131.75 ± 10.60 | 1.1 | 132.81 ± 17.49 | 145.89 ± 20.36 | 137.96 ± 17.29 | 1.0 | |
| Work to Yield /mJ | 1.06 ± 0.18 | 1.11 ± 0.21 | 1.0 | 1.17 ± 0.37 | 1.24 ± 0.15 | 1.27 ± 0.41 | 1.1 | |
| Post-yield Work /mJ | 6.56 ± 1.82 | 10.74 ± 4.04* | 1.6 | 5.49 ± 1.70 | 7.10 ± 1.89 | 8.40 ± 2.21& | 1.5 | |
| Total Work /mJ | 7.63 ± 1.91 | 11.85 ± 3.92* | 1.6 | 7.04 ± 1.76 | 8.34 ± 1.90 | 9.67 ± 2.18* | 1.4 | |
| Yield Stress /MPa | 122.32 ± 17.77 | 121.27 ± 23.32 | 1.0 | 141.33 ± 24.53 | 136.07 ± 21.82 | 137.54 ± 21.95 | 1.0 | |
| Ultimate Stress /MPa | 167.32 ± 15.04 | 167.57 ± 19.55 | 1.0 | 175.19 ± 16.67 | 169.20 ± 20.28 | 175.65 ± 11.10 | 1.0 | |
| Modulus /GPa | 6.07 ± 0.87 | 5.97 ± 1.04 | 1.0 | 7.08 ± 0.88 | 6.58 ± 1.61 | 6.99 ± 0.65 | 1.0 | |
| Resilience /MPa | 1.49 ± 0.27 | 1.48 ± 0.34 | 1.0 | 1.70 ± 0.48 | 1.71 ± 0.16 | 1.71 ± 0.50 | 1.0 | |
| Toughness /MPa | 10.73 ± 3.00 | 15.68 ± 4.94* | 1.5 | 10.40 ± 3.06 | 11.50 ± 2.42 | 13.24 ± 3.59 | 1.3 | |
| 9-month-old | Yield Force /N | 16.13 ± 2.43 | 17.15 ± 3.34 | 1.0 | 17.58 ± 3.56 | 18.60 ± 2.40 | 20.32 ± 2.74 | 1.2 |
| Ultimate Force /N | 24.87 ± 3.98 | 26.91 ± 4.57 | 1.0 | 26.28 ± 3.26 | 25.71 ± 3.24 | 30.46 ± 4.13* | 1.2 | |
| Stiffness /(N·mm−1) | 139.76 ± 20.33 | 143.02 ± 27.30 | 1.0 | 154.53 ± 25.42 | 155.59 ± 16.89 | 180.47 ± 21.22* | 1.2 | |
| Work to Yield /mJ | 1.16 ± 0.24 | 1.26 ± 0.34 | 1.0 | 1.22 ± 0.34 | 1.37 ± 0.30 | 1.43 ± 0.28 | 1.2 | |
| Post-yield Work /mJ | 4.93 ± 2.29 | 5.71 ± 2.29 | 1.1 | 3.69 ± 1.05 | 4.05 ± 1.84 | 6.05 ± 2.27* | 1.6 | |
| Total Work /mJ | 6.09 ± 2.32 | 6.97 ± 2.28 | 1.1 | 4.91 ± 1.13 | 5.42 ± 1.63 | 7.48 ± 2.16* | 1.5 | |
| Yield Stress /MPa | 117.19 ± 19.90 | 118.24 ± 28.61 | 1.0 | 110.70 ± 44.64 | 120.44 ± 21.11 | 121.36 ± 14.13 | 1.1 | |
| Ultimate Stress /MPa | 179.05 ± 19.08 | 184.03 ± 32.90 | 1.0 | 158.61 ± 44.32 | 165.91 ± 23.45 | 181.69 ± 19.05 | 1.1 | |
| Modulus /GPa | 6.44 ± 1.08 | 6.17 ± 1.58 | 0.9 | 5.63 ± 2.52 | 6.38 ± 1.14 | 6.70 ± 0.90 | 1.2 | |
| Resilience /MPa | 1.33 ± 0.3 | 1.38 ± 0.39 | 1.0 | 1.32 ± 0.47 | 1.41 ± 0.36 | 1.38 ± 0.24 | 1.0 | |
| Toughness /MPa | 6.85 ± 2.22 | 7.65 ± 2.61 | 1.1 | 5.16 ± 1.30 | 5.49 ± 1.53 | 7.24 ± 2.10* | 1.4 | |
males:
* = FMR1y/− versus FMR1y/+ by two-tailed Student’s t-test
females:
* = versus FMR1+/+ by one way ANOVA (Multiple comparisons versus Wild Type Group, Holm-Sidak Method)
& = versus FMR1+/+ by one way ANOVA on RANKS (Multiple comparisons versus Wild Type Group - Dunn’s Method)
Detailed statistical analyses are included in Table S5 (males) and S6 (females)