Effects of Combined Intermittent Stretching and Clenbuterol on Disuse Atrophy in Rat Soleus Muscle.

预防或抑制废用性肌萎缩是物理治疗的重要任务。对于长时间躺在床上的病人来说，他们的身体很难承受过重的负荷。间歇性负重（IWB）被认为是一种安全的干预手段，以维持这类患者的腿部肌肉。然而，由于单独使用IWB很难完全预防萎缩，作者以前报道过使用IWB和瘦肉精（Cb）联合治疗。本研究旨在评估间歇性拉伸（IST）和Cb结合的效果。方法：雄性Wistar大鼠分为5组：对照组（CON）、后肢减重组（HU）、HU组（Cb）中Cb处理组（Cb）、HU组（IST）中IST组（Cb+IST）和HU组（Cb+IST）中Cb+IST联合处理组（Cb+IST）。分析：治疗开始后14天切除比目鱼肌，测量肌纤维的横截面积（CSA）、每种纤维类型的百分比和收缩特性。结果：1型纤维CSA相对于CON组（=100%），Cb组为81.0%，IST组为58:3%，Cb+IST组为74.2%。相对于CON组，Cb组抽搐张力为33.9%，IST组为50.3%，Cb+IST组为45.9%。讨论与结论：IWB包括通过拉伸比目鱼肌来锻炼患者，并诱导适当的肌肉工作来承受体重。IST仅涉及肌肉拉伸和等长阻力运动，这些运动不能提供足够的刺激来增强Cb的功效。然而，由于IST是一种有助于诱导肌肉紧张的物理治疗技术，因此可以通过修改应用这种联合治疗的方法来提高Cb+IST联合治疗的有效性。

INTRODUCTION: Prevention or suppression of disuse muscle atrophy is an important task of physical therapy. For patients lying on bed for prolonged periods of time, it is difficult to accommodate the excessive loads borne on their body. Intermittent weight bearing (IWB) is found to be a safe means of intervention to maintain the leg muscles of such patients. However, since complete prevention of atrophy is difficult to achieve with IWB alone, the authors have previously reported on treatment using a combination of IWB and clenbuterol (Cb). The present study was aimed at evaluating the effects of a combination of intermittent stretching (IST) and Cb. METHODS: Male Wistar rats were divided into five groups: control (CON), hindlimb unweighting (HU), Cb treatment during HU (Cb), IST during HU (IST), and combined Cb+IST during HU (Cb+IST) group.ANALYSIS: The soleus muscle was removed 14 days after the start of treatment to measure cross-sectional area (CSA) of muscle fibers, percentage of each fiber type, and contractile properties. RESULTS: The CSA of type 1 fiber, relative to CON group (=100%), was 81.0% in Cb group, 58:3% in IST group and 74.2% in Cb+IST group. Twitch tension, relative to CON group, was 33.9% in Cb group, 50.3% in IST group and 45.9% in Cb+IST group. DISCUSSION and CONCLUSION: IWB involves exercising the patient by means of stretching the soleus muscle and inducing the appropriate muscle work needed to bear the body weight. IST involves only muscular stretching and isometric resistant exercise, which do not provide adequate stimulus to reinforce the efficacy of Cb. However, since IST is a technique of physical therapy useful for inducing muscular tension, it may be possible to elevate the effectiveness of combined Cb+IST by modifying the method of applying this combined therapy.