【作者】 张楠楠；

【导师】 李世昌；

【作者基本信息】 华东师范大学 ， 运动人体科学， 2010， 硕士

【摘要】 本实验旨在探索纵跳和游泳对于模拟失重大鼠骨代谢所起的作用及其机制,并将这两种运动模式相比较,分析其对骨代谢影响的差异,通过模拟宇航员登入太空前的预防性训练,对大鼠的骨密度、骨代谢、及成骨细胞特异性转录因子Osterix (Osx)进行定量研究,探究其原因,间接的为环境对发育中骨量的影响、骨量丢失过程中各种干预手段的运用以及运动方式的选择等提供必要的理论依据,为宇航员模拟失重、升入太空之前的训练模式提供一些参考。【目的】1、探讨不同形式的运动对模拟失重大鼠骨密度的影响；2、探讨不同形式的运动对模拟失重大鼠骨代谢生化指标(骨钙素,抗酒石酸酸性磷酸酶)的影响；3、探讨不同形式的运动对模拟失重大鼠成骨细胞特异性转录因子Osterix的影响；4、分析运动对模拟失重是否有预防作用,并探讨哪种运动方式所起的作用更佳,从而为骨质流失过程中运动干预手段的选择以及运动处方的制订提供理论依据。【方法】建立大鼠纵跳、游泳运动模型,以24只4周龄SD大鼠为实验对象,随机分为3组：安静悬吊组、纵跳悬吊组、游泳悬吊组,每组8只。训练8周后,参照陈杰等改良式大鼠尾部悬吊法,进行2周的尾吊模拟失重,称量体重后将大鼠处死,测骨密度、骨形态结构指标及骨代谢指标。1、观察运动期间大鼠的饮食、活动、毛色、体重变化及尾吊期间大鼠的反应,并做记录。2、运用HOLOGIC Discover A骨密度仪检测大鼠股骨、腰椎骨的骨密度。3、用游标卡尺测量股骨、胫骨的如下形态学指标：长度,中段宽度,中段厚度。4、用酶标仪和南京建成生物公司试剂盒检测模拟失重后大鼠血清中抗酒石酸酸性磷酸酶的水平,用上海锐聪公司试剂盒测血清中骨钙素水平。5、用实时荧光定量PCR技术测定大鼠股骨软骨组织内Osterix表达水平,并探讨其变化机制。【结果】1、实验期间大鼠活动自如、进食不受限。实验开始时测量各组大鼠体重,各组之间无显著差异。经过8周训练后,三组大鼠的体重均有增加,其中纵跳悬吊组和游泳悬吊组大鼠体重较安静悬吊组有显著差异(P<0.05)。尾吊2周后三组大鼠体重均比悬吊前有所下降,但各组大鼠体重之间无显著差异(P>0.05)。2、股骨、胫骨形态计量学指标方面,总体上各组大鼠没有统计学意义上的差异(P>0.05),但是可以发现纵跳悬吊组的股骨长度、胫骨中段宽度和胫骨中段厚度这三项指标与安静悬吊组相比有一定的增高趋势,其他几项无明显增高趋势。3、在股骨的骨密度指标上,纵跳悬吊组明显高于安静悬吊组,二者之间存在极显著性差异(P<0.01)；游泳悬吊组与安静悬吊组之间无统计学差异,但有降低的趋势。4、在椎骨的骨密度指标上,纵跳悬吊组与安静悬吊组相比具有显著性差异(P<0.05)；游泳悬吊组与安静悬吊组相比无显著性差异,有轻微降低的趋势。5、反映骨形成的生化指标骨钙素(OT)水平比较显示,在8周训练加2周模拟失重后,纵跳悬吊组的OT水平与安静悬吊组相比显著升高(P<0.05),游泳悬吊组的OT水平有升高趋势,但差异无统计学意义(P>0.05)。6、反映骨吸收的生化指标抗酒石酸酸性磷酸酶(StrACP)水平比较显示,与安静悬吊组相比,纵跳悬吊组的StrACP水平与安静悬吊组相比有极显著性下降(P<0.01)；游泳悬吊组与安静悬吊组相比有显著性差异(P<0.05)。7、实时荧光定量PCR检测Osx mRNA发现,与安静悬吊组相比,纵跳悬吊组的OsxmRNA含量增高,呈显著性趋势(P<0.05),游泳悬吊组大鼠虽有增高趋势,但无统计学意义上的差异(P>0.05)。【结论】1、研究发现悬吊可以使骨密度、骨形成活动、血清骨代谢生化指标及股骨、胫骨形态学指标降低；悬吊对骨发育的作用机理主要是抑制骨形成,而运动能在很大程度上抑制该过程的发生。2、比较了纵跳与游泳两种运动方式之间的差异,发现不同形式的运动对模拟失重大鼠骨流失的预防作用有着明显的不同。8周的运动训练对尾吊大鼠的股骨和腰椎骨密度、骨代谢生化指标以及股骨、胫骨形态计量学指标都有明显的改变,其中纵跳悬吊组在大部分指标上优于游泳悬吊组,说明纵跳运动比游泳运动能有效促进骨形成,可以在较小的强度作用下对骨代谢产生较大的影响。3、运动引起的骨代谢变化与局部细胞因子对骨组织的影响有关。初步探索了运动与成骨细胞特异性转录因子Osterix(Osx)之间的联系,分析运动对Osx的影响,以及Osx对骨代谢的影响,认为运动可能通过促进Osx的表达从而促进骨形成,且中等强度的纵跳运动优于游泳运动。更多还原

【Abstract】 This study was designed to explore the mechanism of vertical jump and swimming for the prevention of simulated weightlessness on bone in rats, and compared these two sports models to analyze their different impacts on bone metabolism. By simulating the preventive training before astronauts landing the space, I conducted quantitative research on rats’bone density, bone mechanism and the osteoblast-specific transcription factor Osterix(Osx), so as to explore the causes, and indirectly provide the necessary theoretical basis for the environmental impact on developing bone mass, the use of various interventions in recovery process, and the choices of different movements, as well as offer some references to the pre-training before the astronauts moving into space.[Objective]1. Study the effects of different forms of exercise on BMD in simulated weightlessness rats;2. Study the effects of different forms of exercise on the biochemical indexes of bone metabolism (BGP, StrACP) in simulated weightlessness rats;3. Study the effects of different forms of exercise on the osteoblast-specific transcription factor Osterix(Osx) in simulated weightlessness rats.4. Analysed whether exercise have precautionary effects, and which movement pattern is much better, so as to offer a theoretical basis for the choice of movement and the formulation of exercises prescriptions during bone loss.[Method]Set up the rat vertical jump, swimming exercise model, choose twenty four 4-week-old SD rats as subjects and randomly divide them into 3 groups:Quiet & tail-suspended group, jump & tail-suspended group, and swimming & tail-suspended group. After 8 weeks training, make 2 weeks of tail-suspension according to Chen jie’s model of the rat tail-suspension and improved methods. After 2 weeks of tail-suspension, test their body weight, then killing the rats, test their bone mineral density, bone morphology index and bone metabolic markers.1. Observe the rats’diet, activity, coat color, weight and their response during exercise and tail-suspension, and take notes.2. Using HOLOGIC Discover A to detect the rats’femur bone and lumbar bone’s BMD.3. Measure the length, mid-width and mid-thickness of femur and tibia by using the vernier callipers.4. Use the microplate reader and the kit which bought from Nanjing Jiancheng Biology Company to detect the tartrate-resistant acid phosphatase levels in rats’blood, and use the kit which bought from Shanghai Ruicong Company to detect the osteocalcin levels in blood.5. Measure the level of Osterix (Osx) in femur cartilage tissue by the technique of real-time fluorescence quantitative PCR, and explore the mechanism of the variations.[Result]1. During experiment the rats moved and ate freely. At the outset of the experiment, there are no differences between the three groups on weight. After 8 weeks’training, the weights of them are all increased. The jump & tail-suspended group and swimming & tail-suspended are obviously different from the quiet & tail-suspended group on weight (P<0.05). After 2 weeks tail-suspending the weights of those rats are all decreased, but the difference is not obvious (p>0.05).2. Compare the morphological indicators of femur and tibia in the rat:statistically there are no significant differences in general (P>0.05), but we can find that the length of femur, the mid-width and mid-thickness of tibia in jump & tail-suspended group have an increasing tendency.3. Compare the BMD of femur in the rat:The jump & tail-suspended group has obvious difference compared with the quiet & tail-suspended group (P<0.01); the swimming group shows the decreased trend on BMD compared with the quiet & tail-suspended group, and the difference is not obvious (P>0.05).4. Compare the BMD of tibia in the rat:The jump & tail-suspended group has obvious difference compared with the quiet & tail-suspended group (P<0.05); the swimming group shows the decreased trend on BMD compared with the quiet & tail-suspended group, and the difference is not obvious (P>0.05).5. Compare the level of OT in the rat:The jump & tail-suspended group has obvious difference on the level of OT compared with the quiet & tail-suspended group (P<0.05); the swimming & tail-suspended group has no obvious difference on the level of OT compared with the quiet & tail-suspended group (P>0.05).6. Compare the level of StrACP in the rat:The jump & tail-suspended group have remarkable difference on the level of StrACP compared with the quiet & tail-suspended group (P<0.01); the swimming & tail-suspended group have obvious difference on the level of StrACP compared with the quiet & tail-suspended group (P<0.05).7. Use the real-time fluorescence quantitative PCR to detect the expression of Osterix imRNA. The jump& tail-suspended group has obvious increase on the level of Osx mRNA, compared with the quiet & tail-suspended group (P<0.05); and the swimming & tail-suspended group has an increasing tendency, but has no statistically significant differences(p>0.05).[Conclusion]1. The study found that tail-suspending can lower the level of bone density, bone forming activities, bone metabolic biochemical indicators, and the morphology index of femur and tibia. The main formation mechanism of tail-suspending is inhibiting the bone absorption, and exercise could curb the occurrence of the process to a great extent.2. Compared the difference between vertical jump and swimming, and found that different kinds of movement patterns have different effects on preventing bone loss in simulated weightlessness rats. After 8 weeks of training, the levels of BMD, bone metabolic biochemical indicators, and the morphology index in femur and tibia have obvious changes. The jump & tail-suspended group is better than swimming & tail-suspended group on most indices, thus show that jump can effectively promote the formation of bone, and can make great effects on bone metabolism with smaller strength.3. The metabolic change caused by exercise is relevant to the effect of local factor made to the bone tissue. Make a preliminary exploration on the relationship between exercise and osteoblast specific transcription factor Osterix(Osx), analyze the exercise effect on Osx, and the Osx effect on bone metabolism. Think that sports might promote the bone formation by promoting the expression of Osx, and the moderate jump exercise is superior than swimming.更多还原