Shaw S R, Zernicke R F, Vailas A C, DeLuna D, Thomason D B, Baldwin K M
J Biomech. 1987;20(3):225-34. doi: 10.1016/0021-9290(87)90289-2.
The influences of weightbearing forces on the structural remodeling, matrix biochemistry, and mechanical characteristics of the rat tibia and femur and surrounding musculature were examined by means of a hindlimb suspension protocol and highly intensive treadmill running. Female, young adult, Sprague-Dawley rats were designated as either normal control, sedentary suspended, or exercise suspended rats. For 4 weeks, sedentary suspended rats were deprived of hindlimb-to-ground contact forces, while the exercise suspended rats experienced hindlimb ground reaction forces only during daily intensive treadmill training sessions. The suspension produced generalized atrophy of hindlimb skeletal muscles, with greater atrophy occurring in predominantly slow-twitch extensors and adductors, as compared with the mixed fiber-type extensors and flexors. Region-specific cortical thinning and endosteal resorption in tibial and femoral diaphyses occurred in conjunction with decrements in bone mechanical properties. Tibial and femoral regional remodeling was related to both the absence of cyclic bending strains due to normal weightbearing forces and the decrease in forces applied to bone by antigravity muscles. To a moderate extent, the superimposed strenuous running counteracted muscular atrophy during the suspension, particularly in the predominantly slow-twitch extensor and adductor muscles. The exercise did not, however, mitigate changes in bone mechanical properties and cross-sectional morphologies, and in some cases exacerbated the changes. Suspension with or without exercise did not alter the normal concentrations of collagen, phosphorus, and calcium in either tibia or femur.
通过后肢悬吊方案和高强度跑步机跑步，研究了负重力量对大鼠胫骨、股骨及其周围肌肉组织的结构重塑、基质生物化学和力学特性的影响。将雌性成年Sprague-Dawley大鼠分为正常对照组、久坐悬吊组或运动悬吊组。在4周的时间里，久坐悬吊组大鼠被剥夺后肢与地面的接触力，而运动悬吊组大鼠仅在每日高强度跑步机训练期间受到后肢地面反作用力。悬吊导致后肢骨骼肌普遍萎缩，与混合纤维类型的伸肌和屈肌相比，主要为慢肌纤维的伸肌和内收肌萎缩更严重。胫骨和股骨干的特定区域皮质变薄和骨内膜吸收与骨力学性能下降同时发生。胫骨和股骨的区域重塑与正常负重力量导致的周期性弯曲应变缺失以及抗重力肌肉施加于骨的力量减少有关。在一定程度上，叠加的剧烈跑步抵消了悬吊期间的肌肉萎缩，尤其是在主要为慢肌纤维的伸肌和内收肌中。然而，运动并没有减轻骨力学性能和横截面形态的变化，在某些情况下还加剧了这些变化。无论有无运动，悬吊均未改变胫骨或股骨中胶原蛋白、磷和钙的正常浓度。
