Introduction
Materials and methods
Development of a new breaking test for the trochanteric region of the rat femur
Comparative bioassay
Experimental animals and substances
Intravital fluorochrome labeling
Biomechanical test
X-ray examination of fracture mode
Bone histomorphometry and cancellous bone structure analysis
Serum analysis
Evaluation and statistics
Results
Comparison of biomechanical parameters of right and left femurs in the new breaking test
Fracture classification
Breaking strength after administration of estradiol or parathyroid hormone
Sham | OVX | Estradiol benzoate | Parathyroid hormone | |||||
---|---|---|---|---|---|---|---|---|
Mean | STD | Mean | STD | Mean | STD | Mean | STD | |
Body weight (g) | 275.6a
| 14.31 | 342.2 | 19.91 | 280.3a
| 12.05 | 324.9b,c
| 19.38 |
Serum analysis | ||||||||
Osteocalcin (ng/ml) | 2a
| 2.0 | 17.78 | 5.64 | 5.347a
| 1.79 | 45.46a,b,c
| 5.22 |
Crosslaps (ng/ml) | 4.04a
| 0.25 | 33.83 | 8.37 | 46.86 | 34.25 | 45.66b
| 19.56 |
Biomechanical test | ||||||||
Maximum load (N) | 192.1a
| 20.49 | 166.03 | 38.36 | 182.92b
| 13.83 | 225.25a,b,c
| 46.55 |
Yield load (N) | 120.2 | 16.48 | 111.57 | 31.33 | 113.14 | 10.04 | 132.00 | 18.69 |
Stiffness (N/mm) | 267.0a
| 26.10 | 235.56 | 40.82 | 237.15b
| 45.40 | 314.87a,b,c
| 72.05 |
Histomorphometry | ||||||||
N.Nd/mm2
| 48.54a
| 5.439 | 34.35 | 6.97 | 40.66b
| 6.24 | 41.32a
| 4.36 |
Tb.Ar (%) | 77.25a
| 10.73 | 57.18 | 13.62 | 61.04b
| 8.27 | 75.65ac
| 9.02 |
Tb.Wi (mcm) | 8.5a
| 1.38 | 7.62 | 0.95 | 7.53b
| 1.25 | 9.80abc
| 1.27 |
B.Dm (mcm) | 3,154 | 135.9 | 3,137 | 280.6 | 3,140 | 161.1 | 3,151 | 124.1 |
Ma.Dm (mcm) | 1,814 | 67.78 | 1,838 | 221.4 | 1,792 | 123.4 | 1,615a,b,c
| 132.5 |
B.Dm/Ma.Dm | 1.740 | 0.063 | 1.716 | 0.08 | 1.749 | 0.069 | 1.938a,b,c
| 0.069 |
Histomorphometric changes in the proximal femur after administration of estradiol and parathyroid hormone
Serum analysis
Results of intravital fluorochrome labeling of cortical bone of proximal rat femur
Sham | OVX | Estradiol benzoate | Parathyroid hormone | ||||||
---|---|---|---|---|---|---|---|---|---|
Mean | STD | Mean | STD | Mean | STD | Mean | STD | ||
Periosteal apposition | |||||||||
Absolute apposition band width (mcm) | |||||||||
Calcein green (days 0–18) | 3.6a
| 1.4 | 9.4 | 4.4 | 1.5a,b
| 0.7 | 11.6b,c
| 8.7 | |
Alizarin red (days 18–24) | 5.2 | 1.3 | 6.4 | 3.7 | 2.3a,b
| 1.4 | 10.4b,c
| 7.9 | |
Tetracycline (days 24–35) | 4.5 | 2.0 | 6.0 | 3.2 | 1.4a,b
| 0.8 | 12.6b,c
| 8.9 | |
Sum | 13.3a
| 21.8 | 5.2a,b
| 34.6b,c
| |||||
Absolute apposition band width per day (mcm) | |||||||||
Calcein green | 0.2a
| 0.1 | 0.5 | 0.2 | 0.08a,b
| 0.04 | 0.6b,c
| 0.5 | |
Alizarin red | 0.9 | 0.2 | 1.1 | 0.6 | 0.4a,b
| 0.2 | 1.7b,c
| 1.3 | |
Tetracycline | 0.4 | 0.2 | 0.5 | 0.3 | 0.1a,b
| 0.07 | 1.1b,c
| 0.8 | |
Sum | 1.5a
| 2.1 | 0.6a,b
| 3.4b,c
| |||||
Endosteal apposition | |||||||||
Absolute apposition band width (mcm) | |||||||||
Calcein green (days 0–18) | 2.0a
| 1.4 | No significant appositions | 2.3a
| 1.2 | 17.8a,b,c
| 3.5 | ||
Alizarin red (days 18–24) | 2.7a
| 2.3 | 3.2a
| 1.7 | 14.0a,b,c
| 3.5 | |||
Tetracycline (days 24–35) | 0 | 0 | 1.4a
| 0.7 | 15.6a,b,c
| 4.6 | |||
Sum | 4.7a
| 6.9a
| 47a,b,c
| ||||||
Absolute apposition band width per day (mcm) | |||||||||
Calcein green | 0.1a
| 0.1 | No significant appositions | 0.1a
| 0.06 | 1.0a,b,c
| 0.2 | ||
Alizarin red | 0.5a
| 0.4 | 0.5a
| 0.3 | 2.3a,b,c
| 0.6 | |||
Tetracycline | 0 | 0 | 0.1a
| 0.06 | 1.4a,b,c
| 0.4 | |||
Sum | 0.6a
| 0.7a
| 4.7a,b,c
|