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目的：研究长期模拟失重对骨的影响．方法：作者使用本室改进的长期尾部悬吊模拟失重大鼠模型，利用物理测量、显微硬度及三点弯曲等试验，观察了９０ｄ模拟失重对大鼠长骨生长及生物力学特性的影响．结果：９０ｄ悬吊组大鼠股骨直径为２．７±０．２ｍｍ，低于对照组的相应值３．３±０．２ｍｍ（Ｐ＜０．０５）；悬吊组股骨的长度为３８．８±１．０ｍｍ，显著长于对照组的相应值３７．５±０．５ｍｍ（Ｐ＜０．０５）．悬吊组大鼠股骨骨干皮质的显微硬度为３０．６±４．１Ｈｖ，显著低于对照组相应值３８．６±４．４Ｈｖ（Ｐ＜０．０５）．经９０ｄ尾部悬吊，大鼠股骨的强度与刚度均较对照组明显降低（Ｐ＜０．０５或Ｐ＜０．０１）．但在肱骨，上述指标在两组大鼠间无明显差异．结论：长期尾悬吊模拟失重使大鼠承重骨机械性能降低，其生长受到明显的影响，骨变细长．但此种作用仅限于后肢的股骨，对前肢肱骨的生长及其力学特性并无此影响．
Objective: To study the effect of long-term simulated weightlessness on bone. METHODS: The authors used this modified long-term tail suspension simulated weightlessness rat model to investigate the effect of 90-day simulated weightlessness on the growth and biomechanical properties of long bones in rats using physical measurements, microhardness and three-point bending tests. Results: The diameter of the femur in the suspension group was 2.7 ± 0.2 mm at 90 days, which was 3.3 ± 0.2 mm lower than that of the control group (P <0.05). The length of the femur in the suspension group was 38. 8 ± 1.0 mm, significantly longer than the corresponding value of the control group 37.5 ± 0.5 mm (P <0.05). The microhardness of the femoral diaphyseal cortex of the suspension group was 30.6 ± 4.1Hv, which was significantly lower than that of the control group (38.6 ± 4.4Hv, P <0.05). After 90 days tail suspension, the strength and stiffness of the femur in rats were significantly lower than those in the control group (P <0.05 or P <0.01). However, in the humerus, there was no significant difference in the above indexes between the two groups of rats. Conclusion: Long-term tail suspension simulated weightlessness reduced the mechanical properties of the bearing bone in rats, its growth was significantly affected, slender slender. However, this effect is limited to the hindlimb of the femur, the forelimb humerus growth and mechanical properties did not affect this.