去卵巢山羊长骨生物力学性能的变化

Bio mechanical Property Changes of Long Bone in Ovariectomized Goats

采用生物力学方法研究雌性山羊双侧卵巢切除后１８０天其长骨生物力学性能的变化。１５±岁雌性成都山羊１０只，体重２２±ｋｇ，随机分为对照组（Ｃｏｎｔｒｏｌ５只）和双侧卵巢切除组（ＯＶＸ５只）。术后１８０天处死动物，取出双侧股，胫，跖，肱，桡和掌骨。用三点弯曲法测整体骨弯曲结构力学性能的变化。分别取断端密质骨，用三点弯曲，压缩和拉伸方法测骨试件的材料力学特性的变化。结果显示：与对照组比较，双侧卵巢切除组各长骨相应的骨密度，断端骨组织厚度和整体三点弯曲的破坏荷载均明显下降（Ｐ＜００５）；除股骨外，各长骨的整体三点弯曲极限强度，弹性模量和骨试件的弯曲与压缩极限强度，弹性模量以及部分长骨拉伸极限强度明显低于对照组（Ｐ＜００５）。本研究结果提示：雌性山羊双侧卵巢切除后１８０天，其长骨的整体抗弯强度和骨试件的抗弯，抗压，以及抗拉强度均有不同程度的下降，易于骨折。这与临床绝经后妇女雌激素降低，导致骨质疏松，使骨折的倾向性增大是一致的；也与大鼠双侧卵巢切除骨质疏松模型所表现出的骨结构变化和骨量减少相符合。作者认为，骨生物力学参数是评价骨质疏松的重要指标。切除双侧卵巢的雌性山羊有可能成为骨质疏松的大动物模型。

This paper presents the biomechanical property changes of long bone in goats at 180 days after ovariectomy.10 female goats at the age of 1.5 ± years(average body wight 22kg) were randomly divided into the control group and ovariectomized group. These goats were sacrificed at 180 days after ovariectomy and the femora,tibiae,metatarsus,humeri,radius and metacarpus were taken out bilaterally.The structural mechanical properties of these bones were measured with the three point bending method.The material mechanical properties of flexura,compress and tensile in the compact bone specimens taken from the two broken ends were also measured.The results showed that the bone density,bone thickness in broken ends,and the break load of three point bending for the long bones in the OVX group were obviously lower than those in the control group ( P <0 05).And compared with the control group all the long bones in the OVX group,except the femur,had significantly lower ultimate bending strength,bending elastic modulus;ultimate flexural strength,flexural elastic modulus;ultimate compressing strength,and compressing elastic moduus.Some long bones in the OVX group had significantly decreased ultimate tensile strength ( P <0 05).These indicated that the mechanical properties of long bone in OVX group at 180 days after ovariectomy were reduced in varying degrees and were liable to fracture.This result is in accord with the clinical findings in osteoporosis resulting from postmenopausal estrogen fall and is also consistent with the osteoporotic model of ovariectomized rats.The authors conclude that the bone biomechanical properties are important parameters in assessing osteoporosis and the ovariectomized goat can possibly be a good big animal model of osteoporosis.