Three-dimensional morphometry of the L6 vertebra in the ovariectomized rat model of osteoporosis: biomechanical implications.
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.
Kinney
J H
JH
Department of Preventive and Restorative Dental Sciences, University of California, San Francisco 94143-0758, USA.
Haupt
D L
DL
Balooch
M
M
Ladd
A J
AJ
Ryaby
J T
JT
Lane
N E
NE
D000818:Animals; D004195:Disease Models, Animal; D004548:Elasticity; D015914:Estrogen Replacement Therapy; D005260:Female; D021621:Imaging, Three-Dimensional; D008159:Lumbar Vertebrae / Q000648:ultrastructure*; D018625:Microscopy, Atomic Force; D010024:Osteoporosis / Q000473:pathology*; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D017356:Synchrotrons; D014054:Tomography