The aged male rat as a model for human osteoporosis: evaluation by nondestructive measurements and biomechanical testing

• Published in: Calcified tissue international Vol. 53; no. 5; p. 342
• Main Authors: Vanderschueren, D, Van Herck, E, Schot, P, Rush, E, Einhorn, T, Geusens, P, Bouillon, R
• Format: Journal Article
• Language: English
• Published: United States 01.11.1993
• Subjects: Absorptiometry, Photon; Aging - physiology; Androgens - deficiency; Androgens - therapeutic use; Animals; Bone Density - drug effects; Bone Density - physiology; Disease Models, Animal; Femur; Humans; Male; Osteoporosis - physiopathology; Rats; Rats, Wistar; Stress, Mechanical; Tibia
• ISSN: 0171-967X
• DOI: 10.1007/BF01351841

Effects of androgen deficiency and androgen replacement on bone density, as measured with dual-energy X-ray absorptiometry (DXA) and single photon absorptiometry (SPA), cortical ratio (cortical thickness/outside bone diameter x 100), and biomechanical properties were evaluated in 14-month-old (1 month after orchiectomy (orch) or sham-operation) and in 17-month-old (4 months after orch or sham) male rats. Whole femoral bone mineral content (BMC) and density (BMD) measured with DXA were not significantly decreased 1 month after orch. Whole femoral BMC and BMD were 10% and 8% lower in 4 months after orch (P < 0.01 and P < 0.001, respectively). This decrease was prevented by testosterone replacement. There was an excellent correlation (R = 0.99) between whole femoral BMC and femoral ash weight. Selective scanning of cortical and cancellous sites of the femur showed that both cancellous and cortical BMC and BMD were significantly decreased 4 months after orch. SPA of the right tibia confirmed a 7% decrease in cancellous BMC and BMD 4 months after orch (preventable by testosterone) but not in cortical BMD and BMC. Femoral cortical ratio decreased with age (47 +/- 2 in 14-month-old and 40 +/- 2 in 17-month-old sham rats versus 63 +/- 1 in 6-month-old male rats) due to a continuously enlarging femoral shaft. Androgen deficiency resulted in an even greater decrease of the cortical ratio 4 months after orch (36 +/- 2 in 17-month-old orch rats) that was again prevented by testosterone (47 +/- 3).