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

前言：预防或抑制废用性肌肉萎缩是物理治疗的重要任务。长期卧床的病人，身体承受的负荷过大，实在难以适应。间歇性负重（IWB）被认为是一种安全的干预手段，以保持腿部肌肉的患者。然而，由于单独使用IWB很难完全预防萎缩，因此作者以前曾报道过使用IWB和克伦特罗（Cb）联合治疗。本研究的目的是评估间歇性伸展（IST）和Cb组合的效果。方法：将雄性Wistar大鼠分为5组：对照组（CON），后肢减重（HU），HU期间Cb治疗组（Cb），HU期间IST（IST），HU期间Cb + IST联合治疗组（Cb+IST）。分析：比目鱼肌在治疗开始后14天被移除，以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：与CON组（=100%）相比，Cb组的1型纤维CSA为81.0%，IST组为58.3%，Cb +IST组为74.2%。与CON组相比，Cb组、IST组和Cb+IST组的Twitch张力分别为33.9%、50.3%和45.9%。讨论和结论：IWB涉及通过拉伸比目鱼肌并诱导承受体重所需的适当肌肉工作来锻炼患者。IST仅涉及肌肉拉伸和等长阻力运动，其不提供足够的刺激来加强Cb的功效。然而，由于IST是一种可用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联合Cb+IST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.