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

我们研究了自愿阻力运动（攀登）和高蛋白零食（脉冲模式）对糖皮质激素注射（2 mg/kg/天）大鼠骨量和强度的影响，作为年龄相关性骨质减少的模型。将10周龄Wistar大鼠分为低蛋白质（占总食物摄入量的15%）和正常蛋白质（占总食物摄入量的20%）两组。一半大鼠每天在黑暗时段（20:00- 8:00 h）运动。这些组被进一步分成两组，一组在休息期间不吃零食，另一组吃脉冲型高蛋白零食（膳食蛋白质的75%）。各组分别于8:30 ~ 9:30 h和20:30 ~ 21:30 h饲喂正餐，12:30 ~ 13:30 h饲喂零食，连续8周。各组的能量摄入基本相等。锻炼组被迫爬上一个直径20厘米、高200厘米的金属网塔式笼子，从顶部的一个瓶子里喝水。用脉冲型高蛋白零食攀爬可提高骨重和钙含量。攀爬显著增加骨的最大负荷和结构刚度。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，阻力运动可以防止与衰老相关的骨质疏松症的发生。脉冲型高蛋白零食可以增强运动效果。

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.