Sport nutritional study concerning inhibition of sarcopenia and osteopenia with aging in rats

我们研究了自愿抗阻运动（攀登）和高蛋白零食（脉冲模式）对大鼠骨量和强度的影响，这些大鼠接受糖皮质激素注射（2 mg/kg/天），作为年龄相关性骨质减少的模型。Wistar大鼠，10周龄，被分配到低蛋白质（总食物摄入量的15%）或正常蛋白质（20%）饮食组。一半大鼠在黑暗期（20：00-8：00 h）每天运动。这些组被进一步分为在休息期间不接受零食或接受脉冲模式高蛋白质零食（75%的膳食蛋白质）的组。各组分别于8：30-9：30 h和20：30-21：30 h喂食，12：30-13：30 h喂食零食，共8周。所有组的能量摄入量大致相等。运动组被迫爬上一个金属丝网塔笼（直径20厘米×高200厘米），从顶部的瓶子里喝水。骨骼重量和钙含量增加攀登与脉冲模式高蛋白零食。攀爬显著增加了骨骼最大载荷和结构刚度。然而，在低蛋白质喂养组和正常蛋白质喂养组之间没有观察到骨量或强度的差异。这些结果表明，抗阻运动可以防止与衰老相关的骨质疏松症的发展。脉冲式高蛋白零食可以增强运动的效果。

We examined the effects of a voluntary resistance exercise (climbing) together with high-protein snacks (pulse pattern) on bone mass and strength in rats given glucocorticoid-injections (2 mg/kg/day) as a model of age-related osteopenia. Wistar rats, 10 weeks of age, were assigned to low protein (15% of total food intake) or normal protein (20%) diet groups. Half of the rats were exercised daily during dark period (20:00-8 : 00 h). These groups were further divided into groups that received no snack or a pulse pattern high-protein snack (75% of dietary protein) during resting period. All groups were meal-fed at 8:30-9:30 h and 20:30-21:30 h and the snack was fed at 12:30-13:30 h for 8 weeks. Energy intake was approximately equal in all groups. The exercise groups were forced to climb a wire-mesh tower cage (20 cm diameter x 200 cm height) to drink water from a bottle set at the top. Bone weight and calcium content were increased by climbing with pulse pattern high-protein snacks. Climbing significantly increased bone maximum load and structural stiffness. However, no differences in bone mass or strength were observed between low and normal protein feeding groups. These results suggest that resistance exercise protects against the development of osteoporosis associated with aging. Pulse pattern high-protein snacks may enhance the effects of exercise.