Yao Xiaolin, Yun Xiaofei, Chen Tianhua, Chen Mengshi, He Xueling, Long Weifu, Chen Shiqian, Li Liang
Institute of Biomedical Engineering, West China Medical Center, Sichuan University, Chengdu 610041, China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2008 Jun;25(3):626-31, 636.
This study was aimed at observing the effects of ovariectomy and estradiol on the microarchitecture of cancellous bone and exploring the influence of microarchitectural change on the biomechanical properties. Thirty 6-month-old unmated female SD rats were randomly divided into 3 groups (10 rat each): sham-operated control group (Sham), ovariectomized group (OVX)and Estradiol Benzoate treated group (EBT). All rats were housed in standard environmental conditions. Five months after operation, the rats were sacrificed. The biomechanical properties of the third lumbar vertebras (L3) were measured with compression testing in vitro. Micro-CT scanning was performed on the fourth lumbar vertebras (L4) in vitro. In comparison with the corresponding variables of Sham, the bone volume fraction (BV/TV) and the trabecular number (Tb. N) of OVX were reduced remarkably, and the trabecular separation (Tb. Sp) and the structural model index (SMI) of OVX were enhanced obviously. These facts implicated that the bone trabecular plate-like structure of OVX were decreased. BV/TV, Tb. N and the trabecular thickness (Tb. Th) of EBT were greater than those of OVX. Tb. Sp and SMI of EBT were much smaller than those of OVX. The results of mechanical test showed that the maximum forioe (Fmax), the maximum stress (sigmamax) and the elastic modeulus (E) of the lumbar vertebral cancellous bone of OVX were declined sharply, while the aforesaid biomechanical index of EBT was improved distinctly. The performance of three-dimensional micro-CT and the mechanical testing to assess microarchitecture of cancellous bone are useful for evaluating the state of osteoporosis and the antiosteoporotic effect of agents.
本研究旨在观察去卵巢及雌二醇对松质骨微观结构的影响，并探讨微观结构变化对生物力学性能的影响。将30只6月龄未交配的雌性SD大鼠随机分为3组（每组10只）：假手术对照组（Sham）、去卵巢组（OVX）和苯甲酸雌二醇治疗组（EBT）。所有大鼠均饲养在标准环境条件下。术后5个月，处死大鼠。对第三腰椎（L3）进行体外压缩试验以测量其生物力学性能。对第四腰椎（L4）进行体外Micro-CT扫描。与Sham组的相应变量相比，OVX组的骨体积分数（BV/TV）和骨小梁数量（Tb.N）显著降低，而OVX组的骨小梁间距（Tb.Sp）和结构模型指数（SMI）明显增加。这些事实表明OVX组的骨小梁板状结构减少。EBT组的BV/TV、Tb.N和骨小梁厚度（Tb.Th）均大于OVX组。EBT组的Tb.Sp和SMI远小于OVX组。力学测试结果表明，OVX组腰椎松质骨的最大力（Fmax）、最大应力（sigmamax）和弹性模量（E）急剧下降，而EBT组的上述生物力学指标明显改善。三维Micro-CT和力学测试评估松质骨微观结构的性能有助于评估骨质疏松状态及药物的抗骨质疏松效果。
