目的 研究模拟微重力条件对小鼠骨代谢的影响。方法 8周龄野生型C57小鼠,分别尾悬吊0周(对照组)、2周、4周,检测小鼠血清生化指标(Ca²⁺、ALP、BGP);分离股骨行Micro-CT扫描,检测股骨微观结构的改变;三点弯曲试验检测股骨的力学性能。所得数据用SPSS18.0进行统计学分析。结果 与对照组相比,尾悬吊2、4周组小鼠血清Ca²⁺浓度依次升高,而血清ALP、BGP浓度逐渐降低:血清Ca²⁺在悬吊0、2、4周值为(2.134±0.081)mmol/L,(2.261±0.079)mmol/L,(2.388±0.061)mmol/L,与对照组相比具有统计学意义(P<0.05);血清ALP浓度为(4.598±0.478)U/100 ml,(3.447±0.393)U/100 ml,(3.142±0.328)U/100 ml,差异具有统计学意义;血清BGP浓度(8.529±0.523)ng/ml、(8.108±0.392)ng/ml、(7.832±0.282)ng/ml。股骨Micro-CT扫描结果显示:悬吊组小鼠股骨骨小梁数量减少,间隙增大,厚度降低,其中以骨体积比下降最为明显,悬吊2、4周值为对照组的47.3%、14.3%。三点弯曲结果显示尾悬吊后股骨极限强度及弹性模量均降低,对力耐受减弱,对照组、悬吊2、4周股骨骨折断裂能量为(6.220±0.482)mJ;(4.395±0.301)mJ;(2.855±0.425)mJ,与对照组相比具有统计学意义(P<0.05)。结论 尾悬吊法能造成小鼠骨钙流失和骨质疏松,且严重程度与悬吊时间成正相关。

Objective To study the effect of microgravity on the bone itself and metabolism.Methods 8-week-old widetype C57 mice were tail-suspended for 0, 2, 4, weeks. Related serum biochemical indices (Ca²⁺, ALP, BGP) were measured. Microstructure of bone was observed by micro-CT scanning. Three point bending test on the femurs by material testing machine helped to compare the changes of mechanical parameters. All the data were analysed.by SPSS18.0.Results Compared with control group, tail-suspended groups had a higher concentration in calcium in serum,the values of which were (2.134±0.08114) mmol/L, (2.261±0.07913) mmol/L, and (2.388±0.06112) mmol/L; lower levels of serum ALP and BGP, the difference was significant with a longer tail-suspension. The values of ALP was (4.598±0.4783) U/100 ml, (3.447±0.3930) U/100 ml, and (3.142±0.3280) U/100 ml; and the values of BGP were (8.529±0.5233) ng/ml, (8.108±0.3920) ng/ml, and (7.832±0.2821) ng/ml, which had statistically significant difference compared with control group (P<0.05).The scanning of femur showed obviously osteoporosis in tail-suspended mice. Compared with control group, number of bone trabecular reduced, the gap between them widened, thickness decreased simultaneously in the tail-suspended mice. Among which, BV/TV decreased most, the values of tailed-suspension for 2 and 4 weeks were 47.3% and 14.3% in the control group; There was a positive relationship between the osteoporosis and the time of tail-suspension. Mechanical parameters showed that the force decreased as well. Simulated microgravity promoted the loss of calcium in bone, mechanical properties of femurs of suspended-mice decreased, their capability of resistance to force decreasedas well. The forces to bone fracture in tailed-suspension for 0, 2 and 4 weeks were (6.220±0.482)mJ, (4.395±0.301)mJ, and (2.855±0.425)mJ, which had statistically significant difference compared with control group (P<0.05).Conclusions Simulated microgravity promotes the loss of calcium in bone, which can lead to osteoporosis, and the degree of that has a positive relationship to the time.