Sun L W, Blottner D, Luan H Q, Salanova M, Wang C, Niu H J, Felsenberg D, Fan Y B
Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China.
J Musculoskelet Neuronal Interact. 2013 Jun;13(2):166-77.
Human performance in microgravity is characterized by reversed skeletal muscle actions in terms of active vs. passive mode contractions of agonist/antagonist groups that may challenge principal biodynamics (biomechanical forces translated from muscle to bone) of the skeletal muscle-bone unit. We investigated active vs. passive muscle motions of the unloaded hindlimb skeletal muscle-bone unit in the 21 days tail-suspended (TS) rat using a newly designed stepper exercise device. The regimen included both active mode motions (TSA) and passive mode motions (TSP). A TS-only group and a normal cage group (CON) served as positive or negative controls. The muscle and bone decrements observed in TS-only group were not seen in the other groups except TSP. Active mode motions supported femur and tibia bone quality (5% BMD, 10% microtrabecular BV/TV, Tb.Th., Tb.N. parameters), whole soleus muscle/myofiber size and type II distribution, 20% increased sarcolemma NOS1 immunosignals vs. CON, with 25% more hybrid fiber formation (remodeling sign) for all TS groups. We propose a new custom-made stepper device to be used in the TS rat model that allows for detailed investigations of the unique biodynamic properties of the muscle-bone unit during resistive-load exercise countermeasure trials on the ground or in microgravity.
在微重力环境下，人类的表现具有以下特点：在主动肌/拮抗肌群的主动收缩与被动收缩模式方面，骨骼肌动作发生逆转，这可能会对骨骼肌-骨骼单元的主要生物动力学（从肌肉传递到骨骼的生物力学力）构成挑战。我们使用一种新设计的步进运动装置，研究了21天尾悬吊（TS）大鼠中后肢无负荷骨骼肌-骨骼单元的主动与被动肌肉运动。该方案包括主动模式运动（TSA）和被动模式运动（TSP）。仅尾悬吊组和正常笼养组（CON）分别作为阳性或阴性对照。除TSP组外，其他组未观察到仅尾悬吊组出现的肌肉和骨骼减量情况。主动模式运动维持了股骨和胫骨的骨质（骨密度5%、微小梁骨体积分数10%、骨小梁厚度、骨小梁数量等参数）、比目鱼肌整体/肌纤维大小以及II型肌纤维分布，与CON组相比，肌膜一氧化氮合酶1免疫信号增加了20%，所有TS组的混合纤维形成（重塑标志）增加了25%。我们提出一种新的定制步进装置，用于TS大鼠模型，该装置可在地面或微重力环境下的抗阻负荷运动对策试验中，对肌肉-骨骼单元独特的生物动力学特性进行详细研究。
