一种新的测试胫骨骨生物力学特性的三点弯曲方法

比较胫骨干骺端三点弯曲法与传统胫骨骨干三点弯曲法评价骨质疏松大鼠胫骨生物力学特性变化的差异与敏感性.6月龄未交配雌性SD大鼠20只,随机分为假手术组(Sham)和去卵巢组(OVX).术后相同环境饲养5个月,处死大鼠,取左侧胫骨,分别采用胫骨干骺端三点弯曲法和传统胫骨骨干三点弯曲法测定胫骨骨生物力学参数的变化.与相应的Sham组比较,胫骨干骺端三点弯曲法测得的大鼠胫骨骨破坏荷载、破坏应力、最大荷载、最大应力、弹性模量均明显降低(P＜0.05),而采用胫骨骨干三点弯曲测得上述骨生物力学参数均无明显变化(P＞0.05).在评价骨质疏松大鼠的胫骨的生物力学参数方面,胫骨干骺端三点弯曲法比胫骨骨干三点弯曲法更为敏感.

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.