大鼠股骨干骺端弯曲试验：一种用于骨质疏松症的新型生物力学测试方案的介绍与验证

Femoral metaphysis bending test of rat: introduction and validation of a novel biomechanical testing protocol for osteoporosis.

作者信息

Chen BaiLing, Li YiQiang, Yang XiaoXi, Xie DengHui

机构信息

Department of Spine Surgery, The First Affiliated Hospital of Sun Yat-sen University, 510080 Guangzhou, China.

出版信息

J Orthop Sci. 2012 Jan;17(1):70-6. doi: 10.1007/s00776-011-0167-7. Epub 2011 Nov 2.

DOI:10.1007/s00776-011-0167-7

PMID:22045451

Abstract

BACKGROUND

The diaphysis bending test is generally accepted to assess the biomechanical properties of bone in osteoporotic animals. However, bone strength loss was more pronounced at the metaphysis than diaphysis. Therefore, the biomechanical test should be focused on the metaphysis. This study aimed to validate a novel biomechanical test for femoral metaphysis in ovariectomized rats.

METHODS

Twenty 5-month-old female Sprague-Dawley rats were randomly divided into the ovariectomized (OVX) and sham-operated (Sham) groups. Examination of femur bone mineral density (BMD) and histomorphometry of the distal femur were performed. Femur biomechanical parameters (maximal load, yield load, and stiffness) were determined by the diaphysis bending test and a novel designed metaphysis bending test. Pearson's correlations were used to analyze the relationships between the biomechanical parameters and BMD or bone histomorphometry indexes (%Tb.Ar, Tb.N, Tb.Th), respectively.

RESULTS

The femur BMD, bone histomorphometry indexes, and biomechanical parameters of OVX were inferior to those of the Sham group (P < 0.05). In the diaphysis bending test, the mean difference of the maximum load and yield load between the OVX and Sham groups were 13.83 ± 5.27 and 15.69 ± 4.15 N, which were significantly lower than in the metaphysis bending test (43.34 ± 4.27, 48.90 ± 4.35 N; all P < 0.05). Positive correlations between biomechanical parameters and femur BMD or bone histomorphometry indexes were observed in both the diaphysis bending and metaphysis bending test. The biomechanical parameters in the metaphysis bending test showed stronger correlations with BMD and bone histomorphometry indexes.

CONCLUSIONS

The femoral metaphysis bending test was validated to assess osteoporosis in our study, and it was more sensitive than the diaphysis bending test in evaluating the change of biomechanical properties of the femur in osteoporotic rats.

摘要

背景

骨干弯曲试验通常被用于评估骨质疏松动物模型中骨的生物力学特性。然而，干骺端的骨强度损失比骨干更为明显。因此，生物力学测试应聚焦于干骺端。本研究旨在验证一种针对去卵巢大鼠股骨干骺端的新型生物力学测试方法。

方法

将20只5月龄雌性Sprague-Dawley大鼠随机分为去卵巢（OVX）组和假手术（Sham）组。对股骨骨密度（BMD）进行检测，并对股骨远端进行组织形态计量学分析。通过骨干弯曲试验和一种新设计的干骺端弯曲试验来测定股骨生物力学参数（最大载荷、屈服载荷和刚度）。分别采用Pearson相关性分析生物力学参数与BMD或骨组织形态计量学指标（%Tb.Ar、Tb.N、Tb.Th）之间的关系。

结果

OVX组的股骨BMD、骨组织形态计量学指标和生物力学参数均低于Sham组（P < 0.05）。在骨干弯曲试验中，OVX组与Sham组之间最大载荷和屈服载荷的平均差异分别为13.83±5.27 N和15.69±4.15 N，显著低于干骺端弯曲试验（43.34±4.27 N、48.90±4.35 N；均P < 0.05）。在骨干弯曲试验和干骺端弯曲试验中均观察到生物力学参数与股骨BMD或骨组织形态计量学指标之间存在正相关。干骺端弯曲试验中的生物力学参数与BMD和骨组织形态计量学指标显示出更强的相关性。