Table 4.
Biomechanical properties of femurs in wild-type and mutant mice
| Genotype | Runx2-II+/+ | Runx2-II+/− | Runx2-II−/− |
|---|---|---|---|
| Max force (N) | |||
| 6 weeks | 25.1 ± 5.4 | 18.7 ± 3.3a (P = 0.0028) | 8.1 ± 2.7a,b (P = 0.0001) |
| 24 weeks | 37.8 ± 6.4c | 29.9 ± 5.1a,c (P = 0.0014) | – |
| (P = 0.0001) | (P < 0.0001) | ||
| Max deflection (mm) | |||
| 6 weeks | 0.85 ± 0.11 | 0.86 ± 0.05 (P = 0.8775) | 0.81 ± 0.09 (P = 0.3397) |
| 24 weeks | 0.56 ± 0.11c | 0.49 ± 0.06c (P = 0.0908) | – |
| (P < 0.0001) | (P < 0.0001) | ||
| Stiffness (N/mm) | |||
| 6 weeks | 48.1 ± 12.5 | 34.3 ± 6.2a (P = 0.0024) | 10.4 ± 3.2a,b (P < 0.0001) |
| 24 weeks | 93.0 ± 16.9c | 77.1 ± 9.4a,c (P = 0.0024) | – |
| (P < 0.0001) | (P < 0.0001) | ||
| Flexural rigidity (N.mm2) | |||
| 6 weeks | 125.2 ± 32.6 | 89.2 ± 16.1a (P = 0.0024) | 27.1 ± 8.2a,b (P < 0.0001) |
| 24 weeks | 242.2 ± 44.0c | 200.8 ± 24.4a,c (P = 0.0024) | – |
| (P < 0.0001) | (P < 0.0001) | ||
Data are mean ± SEM from 5 to 10 individual mice.
a
Significant difference from wild-type Runx2-II+/+ mice.
b
Significant difference from heterozygous Runx2-II+/− mice.
c
Difference between 6 and 24 weeks at the indicated P value using statistical analysis described in Materials and methods.