尾悬吊法小鼠骨质疏松模型的建立与评价

摘要

目的：通过尾悬吊法建立一种废用性小鼠骨质疏松模型并对其进行评价。方法32只C57BL／6J雄性小鼠，采用随机数表法分为4组，即尾悬吊（ tail－suspension， TS）14 d 组及其对照组（ control 1， C1），尾悬吊14 d后解除悬吊14 d组（tail－suspension＋rest， TS＋R）及其对照组（control 2， C2）。采用显微计算机断层扫描（ computed tomography， CT），生物力学和形态学方法评估小鼠骨质流失情况。结果 TS组和TS＋R组股骨长度较各自对照组分别下降8．23％和7．68％。两悬吊组股骨小梁骨密度与各自对照组相比分别下降26．80％和20．52％，骨体积分数，骨小梁厚度、数目也明显下降，骨小梁间隙显著升高， TS组皮质骨密度较C1组下降8．51％。两悬吊组的股骨最大载荷较其对照组分别下降23．01％和18．54％， TS组弯曲弹性模量较C1组下降21．99％， TS与TS＋R两组的下降程度之间比较，差异有统计学意义（ t＝6．462， P＝0．008）。形态学方面， TS和TS＋R组成骨细胞数比各自对照组低47．76％和41．44％，破骨细胞数较各自对照组高30．06％和16．93％，生长板厚度以及软骨细胞数等明显少于各自对照组， TS组胶原纤维面积较其余3组明显缩小。结论雄性C57小鼠尾悬吊14 d表现出显著骨质疏松，解除悬吊14 d后骨质流失状况未显著改善，尾悬吊法小鼠骨质疏松模型具有造模时间短，效果明显、作用稳定等特点，值得进一步推广运用。%Objective To establish a disuse osteoporosis mouse model by tail-suspension and observe its struc-tural and morphological changes and mechanical properties of mice.Methods Thirty two male C57BL/6J mice were randomly divided into 4 groups.TS group:mice were tail-suspended for 14 days.TS+R group: mice were tail-suspen-ded and rest for 14 days respectively.C1 and C2 groups:mice were normally feed for 14 days or 28 days.All mice were sacrificed at predetermined time points.Then micro-CT, biomechanic tests and morphological observations were comple-ted.Results The femural length of TS-treated groups decreased by 8.23%and 7.68%, and bone mineral density de-creased by 26.80%and 20.52% compared with C1 and C2 groups respectively.The bone volume fraction, trabecular bone thickness and number in TS-treated groups were significantly lower than the control groups, while the trabecular se-peration was higher than the control groups.The cortical BMD of TS group declined by 8.51%compared with C1 group. By biomechanical tests, the maximal load of femur in TS-treated groups dropped by 23.01% and 18.54% respectively, the elastic modulus of TS group failed by 21.99%compared with C1 group, and the diversities between TS and TS+R groups and their respective control groups showed a signifcant difference (t=6.462, P=0.008).The results of biome-chanical parameters showed high risk of fracture in TS-treated groups.By histological observation, the number of osteo-blasts decreased by 47.76% and 41.44%, while number of osteoclasts increased by 30.06% and 16.93% compared with C1 and C2 groups respectively.Furthermore, the number of chondrocytes and thickness of growth plate in TS-treated groups were obviously lower than that in the control groups, and the area of collagen in TS group was less than the other three groups.Conclusion Significant changes of mice femurs were seen in TS group, the trabecular bone structure and biomechanical properties were damaged, and histological degeneration was found.Most of bone-associated parameters in TS+R group were stable, even the mice were released for 14 days.These results demonstrate that it is worthful to pro-mote the new osteoporotic mouse model in the furture, because it is effective, steady and timesaving obviously.