EFFECT OF LONG-TERM OVARIECTOMY ON BONE MECHANICAL-PROPERTIES IN YOUNG FEMALE CYNOMOLGUS MONKEYS

Feral adult female cynomolgus monkeys were divided into two groups: no rmal controls and ovariectomized. Tibiae and trabecular bones from the femoral head, from each group, were tested using a materials testing machine. The bending stiffness of the tibiae was measured by nondestru ctive three-point bending tests and their maximum torque capacity by d estructive torsion tests. The compressive strength of the trabecular b ones was measured by compression tests. Ovariectomy caused significant decreases in elastic modulus of the tibiae (p < 0.008), measured by t hree-point bending tests, and in shear modulus (p < 0.015), failure sh ear stress (p < 0.01), and failure torque (p < 0.001) of the tibiae, m easured by torsion tests. It caused a significant decrease in cortical bone density (p < 0.005), but no significant changes in tibial cross- sectional area and in cortical shaft external and internal diameters. The differences in elastic modulus, maximum compressive strength, and density of femoral trabecular bone samples between the two groups were not significant.