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一项重要任务。对于长期卧床的患者来说，很难适应身体承受的过重负荷。间歇性负重(IWB)被发现是维持此类患者腿部肌肉的一种安全的干预手段。然而，由于仅用IWB很难完全预防萎缩，作者先前曾报道过使用IWB和瘦肉精(CB)的联合治疗。本研究旨在评估间歇拉伸(IST)和CB的组合效果。方法：雄性Wistar大鼠分为对照组(CON)、后肢减重(HU)、CB治疗(CB)、HU期间IST(IST)和CB+IST(CB+IST)组。分析：治疗14天后取出比目鱼肌，测量肌纤维横截面积(CSA)、各纤维类型的百分比和收缩特性。结果：与CON组相比，CB组、IST组和CB+IST组的CsA分别为81.0%、58：3%和74.2%。收缩张力：CB组为33.9%，IST组为50.3%，CB+IST组为45.9%。讨论和结论：IWB包括通过拉伸比目鱼肌和诱导适当的肌肉工作来锻炼患者，以承担体重。IST只涉及肌肉伸展和等长抗力训练，这并不能提供足够的刺激来加强CB的疗效。然而，由于IST是一种可用于诱导肌肉张力的物理治疗技术，因此有可能通过改进该联合治疗的应用方法来提高CB+IST的疗效。

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.