[A new three-point bending test for bone biomechanical properties of rat's tibia]

In this study, we compared the three-point bending test of the metaphyseal tibia versus the three-point bending test of the diaphysial tibia in rats. Twenty 6-month-old female Sprague-Dawley rats were randomly divided into the ovariectomized (OVX) group and the sham-operated (Sham) group. All rats were housed in standard environmental conditions. Five months after operation, all rats were sacrificed by depletion method. All left tibia were removed for the three-point bending test. The changes of mechanical parameters were examined by the three-point bending test of the metaphyseal tibia and by that of the diaphysial tibia. Elastic, Maximum Load, Maximum Stress, Failure Load, and Failure Stress of the metaphyseal tibia were much lower in OVX rats than in Sham rats. However, there was no statistically significant difference in all of the mechanical parameters of the diaphysial tibia between the OVX group and the Sham group. The new three-point bending test of the metaphyseal tibia is much more sensitive and useful as compared with the test of the diaphysial tibia in evaluating the changes of mechanical properties of tibia in osteoporotic rats.