悬吊模拟失重及解悬吊对大鼠骨密度及生物力学的影响

目的：观察尾部悬吊模拟失重及解悬吊后大鼠骨密度及生物力学的变化。方法：20只Wistar雄性大鼠随机分成空白组和模型组。模型组尾部悬吊14d,解悬吊后继续饲养14d,空白组则正常饲养28d。实验第14天活体检测各组大鼠颅骨、T2椎体、L4椎体、骨盆、右侧桡尺骨和右侧股骨的骨密度（bone mineral density,BMD）;实验第28天处死大鼠,检测右侧股骨及L4椎体BMD及生物力学强度。结果：与空白组相比,实验第14天,模型组大鼠股骨、骨盆、腰椎BMD明显低,差异有统计学意义（P〈0.001,P〈0.001,P〈0.01）;颅骨、胸椎、桡尺骨BMD无明显变化（P〉0.05）。实验第28天,模型组大鼠股骨、腰椎BMD和股骨最大载荷明显低,差异有统计学意义（P〈0.01,P〈0.001,P〈0.01）。结论：大鼠尾部悬吊14d即可引起骨代谢的紊乱：承重骨骨矿盐大量丢失;即使解悬吊14d后承重骨BMD及力学强度也明显降低,表明骨代谢紊乱短期内不能恢复正常。

Effects on rats' bone mineral density and bone biomechanics by suspensory simulated weightlessness and removing suspension

Objective: To study the effects on rats' bone mineral density and bone biomechanics by suspensory simulated weightlessness and removing suspension. Methods: Twenty Wistar rats were divided into two groups randomly as control group and model group. Suspend the model group rats for 14 days,then remove suspension and continue to feed for another 14 days. Feed control group rats for 28 days. Detect the bone mineral density(BMD)in vivo of cranial bone,second thoracic vertebra,fo- urth lumbar vertebra,pelvis,right radioulna and right femoral bone of each group at the 14th day. At the 28th day,execute all the rats and take out of right femoral bone and fourth lumbar vertebra for detecting BMD and the intensity of biomechanics. Results: At the 14th day in experiment,being compared with control group,the BMD of femoral bone,pelvis and lumbar vertebra in model group decreased significantly(P<0.001,P<0.001,P<0.01)and the change of BMD of cranial bone,thoracic vertebra a- nd radioulna in model group was not remarkable(P>0.05). At the 28th day in experiment,the BMD of femoral bone and lumbar vertebra,the maximal load of femoral bone decreased significantly in model group as compared with control group(P<0.01,P<0.001,P<0.01). Conclusion: BMD in vivo body showed that suspensory simulated weightlessness for 14 days could cause disorder of bone metabolism and remarkable mineral loss of weight bearing bone,even BMD and biomechanical intensity of weight bearing bone decrease obviously when removing suspension for 14 days. The results suggest that the disorder of bone metabolism could not be recovered in short time.