去卵巢大鼠椎骨组织形态计量学、生物力学特点及相关性研究

采用骨组织形态计量学、骨生物力学和骨矿含量测定等方法研究 10 .5月龄至 16月龄 SD大鼠和双侧卵巢去除术后椎骨的骨质量变化以及它们之间的相关关系。雌性 SD大鼠随机分为 6组 :(1) 10 .5月龄基础组 ;(2 )13月龄假手术组 (sham - 1) ;(3) 13月龄去卵巢组 (OVX- 2 ) ;(4) 16月龄假手术组 (sham - 2 ) ;(5 ) 16月龄去卵巢组(OVX- 2 )和 (6 )雌激素治疗组 :去卵巢 10周后给予雌激素治疗 12周 (OVX- 2 +EE)。所有大鼠在处死前 14、13d和4、3d分别皮下注射四环素和钙黄绿素作体内荧光标记。实验终止时取大鼠第 4腰椎行骨组织形态计量学测量 ,第5腰椎体作试件压缩试验 ,试验后的椎体进行骨矿物元素测定。结果发现 10 .5月龄至 16月龄大鼠椎体骨干重、冠状径、骨小梁面积骨小梁厚度有增加趋势 ,骨的破坏荷载 ,破坏应力和弹性模量也有增加趋势 ,以 13月龄为高峰值。去卵巢 10周后 ,上述指标明显下降 ,2 2周后 ,下降更明显。雌激素治疗后上述指标明显改善。相关研究表明 ,骨小梁面积与骨的破坏应力呈正相关 (P<0 .0 5 ) ,而骨的破坏应力又与骨矿 (主要成分 Ca)含量呈正相关 (P<0 .0 1)。去卵巢后 ,骨小梁面积的下降比骨破坏应力的下降更明显 ,出现的时间更早。本研究表明 ,骨组织形态计量学检测和骨生物力学检

Correlative Changes of Histomorphometry and Biomechanical Property of Lumbar Vertebrae Body in Ovariectomized Rats

This paper presents the correlative changes of cancellous bone histomorphometry, biomechanical property and bone mineral contents of lumbar vertebrae in ovariectomized rats. Forty eight 10.5-month-old female SD rats were randomized to six groups: 1) Basal: at 10.5 mon. of age; 2) sham-1: sham-operated at 13 mon. of age; 3) OVX-1: ovariectomized at 13 mon. of age; 4) sham-2: sham-operated at 16 mon. of age; 5) OVX-2: ovariectomized at 16 mon. of age; and 6) OVX-2 + EE: ovariectomized and treated with 17 alpha-ethynylestradiol (100 micrograms.kg-1.d-1) starting at 13 mon. of age for 12 weeks. Double in vivo fluorochrome labeling was administered to all rats. At the end-point of study, the undecalcified longitudinal fourth lumbar vertebra (LV4) sections were cut and stained with Goldner's Trichrome for bone histomorphometric analyses. The mechanical properties of the compact fifth lumbar vertebra body (LV5) were measured with compression test, the LV5 bodies then were dried constantly with high temperature and digested with acid for testing of bone mineral content. A trend in trabecular bone volume (BV/TV), trabecular thickness (Tb.Th) of LV4, bone break load, break stress, elastic moduli and bone calcium content of LV5 to increase with the increase of age was revealed in the intact rats, but the highest value was at 13 mon. of age. A positive correlation was seen between histomophormetry and bone bio-mechanical properties in the intact rats. Compared with the data from the sham-operated rats, the BV/TV and Tb. Th significantly decreased and bone turnover rate significantly increased in OVX rats at 10 weeks, and the above parameters further decreased 22 weeks post OVX. Correspondingly, the bone break load, break stress, elastic moduli and bone calcium content significantly decreased with the increase of time post OVX was compared with those of sham-operated rats. A positive correlation between histomophormetry and bone biomechanical properties was also observed in OVX rats (r = 0.399, P = 0.018). Bone histomorphometry is good for predicting early physiological and pathological changes and bone biomechanical properties are good parameters for predicting corresponding function of bone such as fracture. Both of them are useful and needful in the animal studies on osteoporosis and related pharmacodynamic observations on new drugs.