Three‐Dimensional Morphometry of the L6 Vertebra in the Ovariectomized Rat Model of Osteoporosis: Biomechanical Implications

• Published in: Journal of bone and mineral research 2000-10, Vol.15 (10), p.1981-1991
• Main Authors: Kinney, J. H., Haupt, D. L., Balooch, M., Ladd, A. J. C., Ryaby, J. T., Lane, N. E.
• Format: Article
• Language: English
• Subjects: Animals; atomic force microscopy; Biological and medical sciences; cortical bone; Disease Models, Animal; Diseases of the osteoarticular system; Elasticity; Estrogen Replacement Therapy; Female; Imaging, Three-Dimensional; Lumbar Vertebrae - ultrastructure; Medical sciences; Microscopy, Atomic Force; microtomography; osteoporosis; Osteoporosis - pathology; Osteoporosis. Osteomalacia. Paget disease; Ovariectomy; rat model; Rats; Rats, Sprague-Dawley; Stress, Mechanical; synchrotron radiation; Synchrotrons; Tomography; trabecular bone; vertebra
• ISSN: 0884-0431; 1523-4681
• DOI: 10.1359/jbmr.2000.15.10.1981

This article summarizes the results of a three‐dimensional study of changes in the morphology of the L6 rat vertebra at 120 days after ovariectomy (OVX), with estrogen replacement therapy used as a positive control. Synchrotron radiation microtomography was used to quantify the structural parameters defining trabecular bone architecture, while finite‐element methods were used to explore the relationships between these parameters and the compressive elastic behavior of the vertebrae. There was a 22% decrease in trabecular bone volume (TBV) and a 19% decline in mean trabecular thickness (Tb.Th) with OVX. This was accompanied by a 150% increase in trabecular connectivity, a result of the perforation of trabecular plates. Finite‐element analysis of the trabecular bone removed from the cortical shell showed a 37% decline in the Young's modulus in compression after OVX with no appreciable change in the estrogen‐treated group. The intact vertebrae (containing its trabecular bone) exhibited a 15% decrease in modulus with OVX, but this decline lacked statistical significance. OVX‐induced changes in the trabecular architecture were different from those that have been observed in the proximal tibia. This difference was a consequence of the much more platelike structure of the trabecular bone in the vertebra.