Bagi C M, Ammann P, Rizzoli R, Miller S C
Bayer Corporation, Institute of Bone and Joint Disorders, 400 Morgan Lane, West Haven, Connecticut 06516-4175, USA.
Calcif Tissue Int. 1997 Oct;61(4):336-44. doi: 10.1007/s002239900344.
Eighty mature Sprague-Dawley rats were weight matched before ovariectomy (Ovx) or Sham surgery (Sham). Sham rats had free access to food and water throughout the experiment, whereas Ovx rats were kept on the pair-fed diet. Rats were euthanized at 4, 8, and 12 weeks after surgery, and had received fluorochrome bone markers at 9 and 2 days prior to euthanasia. In addition 10 rats were euthanized at the time of surgery serving as baseline controls. All rats were also scanned for body composition and bone mineral parameters by DEXA before surgery and euthanasia. Left proximal femurs (femoral necks) were used for bone histomorphometry, whereas right femurs were used for in vitro DEXA measurements and mechanical testing. Despite pair-feeding, ovariectomized rats had increased body weights and fat body mass, whereas the percent lean body mass steadily declined throughout the experiment. Mineral density of the whole femur and femoral neck was significantly higher in the Sham rats relative to Ovx animals. Ovariectomy reduced trabecular number and thickness, and increased trabecular separation and bone marrow space at the femoral midneck location. The structure of the remaining trabeculae was dramatically changed toward simpler struts as revealed by nodal analyses. Cortical thickness in Ovx rats was reduced because of the high endocortical resorption, which, in addition to cancellous bone resorption, resulted in fewer endocortico-trabecular connections. Femoral necks obtained from ovariectomized rats had reduced strength and were less stiff relative to controls. Because of the enormous clinical significance of the proximal femur for osteoporosis in humans, and the opportunity for studying bone BMD, mass, structure, and strength at the same skeletal location, the femoral neck appears superior to other skeletal sites routinely used for bone histomorphometry or mechanical testing in the Ovx rat model.
80只成年斯普拉格-道利大鼠在卵巢切除术（Ovx）或假手术（Sham）前进行体重匹配。假手术组大鼠在整个实验过程中可自由获取食物和水，而卵巢切除组大鼠则采用配对喂食饮食。大鼠在手术后4周、8周和12周时实施安乐死，并在安乐死之前9天和2天接受荧光骨标记物。此外，10只大鼠在手术时实施安乐死作为基线对照。所有大鼠在手术前和安乐死时均通过双能X线吸收法（DEXA）扫描身体成分和骨矿物质参数。左近端股骨（股骨颈）用于骨组织形态计量学分析，而右股骨用于体外DEXA测量和力学测试。尽管采用了配对喂食，但卵巢切除组大鼠的体重和脂肪量增加，而瘦体重百分比在整个实验过程中稳步下降。与卵巢切除组动物相比，假手术组大鼠全股骨和股骨颈的矿物质密度显著更高。卵巢切除术减少了股骨中颈部位的小梁数量和厚度，并增加了小梁间距和骨髓腔。节点分析显示，其余小梁的结构向更简单的支柱结构发生了显著变化。卵巢切除组大鼠的皮质厚度因高内皮质吸收而降低，这除了导致松质骨吸收外，还导致内皮质-小梁连接减少。与对照组相比，卵巢切除组大鼠的股骨颈强度降低且刚度较小。由于近端股骨对人类骨质疏松症具有巨大的临床意义，且有机会在同一骨骼部位研究骨密度、质量、结构和强度，因此在卵巢切除大鼠模型中，股骨颈似乎优于其他常用于骨组织形态计量学或力学测试的骨骼部位。
