Muscle atrophy and bone loss after 90 days' bed rest and the effects of flywheel resistive exercise and pamidronate: Results from the LTBR study
Muscle atrophy and bone loss after 90 days' bed rest and the effects of flywheel resistive exercise and pamidronate: Results from the LTBR study
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DOI：
10.1016/j.bone.2004.11.014
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发表时间：
2005-06-01
期刊：
影响因子：
4.1
通讯作者：
Felsenberg, D
中科院分区：
文献类型：
--
作者：
Rittweger, J;Frost, HM;Felsenberg, D
肌肉萎缩和骨质流失对长期空间飞行和临床固定造成了严重问题。因此，我们测试了飞轮抗阻运动和帕米膦酸盐抵消这种损失的功效。25名年轻健康男性进行了严格的卧床休息，头向下倾斜-6度，持续90天。受试者被随机分为运动组、帕米膦酸二钠组和对照组。运动组每2-3天使用“飞轮”（FW）装置进行抗阻运动，帕米膦酸二钠组在卧床休息前14天静脉注射60 mg帕米膦酸二钠，对照组不接受任何措施。采用外周定量计算机断层扫描（pQCT）测定小腿和前臂骨矿含量（BMC）和肌肉横截面积（mCSA）。在基线数据收集期间、卧床休息28天和89天后以及恢复14天后进行两次测量。在同一天，测定尿吡啶啉排泄量和血清碱性磷酸酶、Ca++和PTH水平。通过弗赖堡问卷对研究前的运动习惯进行评估。（对照：-25.6% +/- 2.5% Pam：-25.6% +/-3.7%，FW：-17.3% +/- 2.7%），但未在前臂mCSA中（Ctrl：-6.4% +/-4.33%，Pam：-7.7% +/-4.1%，FW：-7.6% +/- 3.3%）。股骨干和骨骺的骨矿物质损失的胫骨减轻帕姆和FW相比，ctrl.Inter-individual差异显着，但仅在骨干BMC的变化比mCSA，和相关性的BMC损失是穷人之间的不同位置的胫骨。胫骨骨骺骨矿物质含量变化与血清皮质醇水平呈显著正相关，提示两种措施对卧床期间下肢骨矿物质含量（FW和Pam）和mCSA（FW）的保护作用均不完全有效。飞轮运动的部分功效以及骨骼对卸载本身的反应强调了机械刺激的重要性。然而，BMC变化的巨大差异表明，其他因素影响急性机械废用后全骨强度的变化。(c)2004年爱思唯尔公司All rights reserved.
Muscle atrophy and bone loss pose substantial problems for long-term space flight and in clinical immobilization. We therefore tested the efficacy of flywheel resistive exercise and pamidronate to counteract such losses.Twenty five young healthy males underwent strict bed rest with -6 degrees head-down tilt for 90 days. Subjects were randomized into an exercise group that practiced resistive exercise with a 'flywheel' (FW) device every 2-3 days, a pamidronate group (Pam) that received 60 mg pamidronate i.v. 14 days prior to bed rest and a control group (Ctrl) that received none of these countermeasures.During the study, Ca++ and protein intake were controlled. Peripheral quantitative computed tomography (pQCT) was used to assess bone mineral content (BMC) and muscle cross sectional area (mCSA) of calf and forearm. Measurements were taken twice during baseline data collection, after 28 and after 89 days bed rest, and after 14 days recovery. On the same days, urinary Pyridinoline excretion and serum levels of alkaline phosphatase, Ca++ and PTH were measured. Pre-study exercise habits were assessed through the Freiburg questionnaire.Losses in calf mCSA were significantly reduced in FW (Ctrl: -25.6% +/- 2.5% Pam: -25.6% +/- 3.7%, FW: -17.3% +/- 2.7%), but not in the forearm mCSA (Ctrl: -6.4% +/- 4.33%, Pam: -7.7% +/- 4.1%, FW: -7.6% +/- 3.3%). Both diaphyseal and epiphyseal BMC losses of the tibia were mitigated in Pam and FW as compared to Ctrl, although this was significant only at the diaphysis.Inter-individual variability was significantly greater for changes in BMC than in mCSA, and correlation of BMC losses was poor among different locations of the tibia. A significant positive correlation was found between change in tibia epiphyseal BMC and serum cortisol levels.These findings suggest that both countermeasures are only partly effective to preserve BMC (FW and Pam) and mCSA (FW) of the lower leg during bed rest. The partial efficacy of flywheel exercise as well as the bones' response to unloading per se underlines the importance of mechanical stimuli. The huge variability of BMC changes, however, suggests that other factors affect changes in whole-bone strength following acute mechanical disuse. (c) 2004 Elsevier Inc. All rights reserved.