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

2006 Fiscal Year Final Research Report Summary

• Project/Area Number: 17500351
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Rehabilitation science/Welfare engineering
• Research Institution: Kanazawa University
• Principal Investigator: YAMAZAKI Toshiaki Gradtiate School of Medical Science, Professor, 医学系研究科, 教授 (00220319)
• Co-Investigator(Kenkyū-buntansha): YOKOGAWA Masami Graduate School of Medical Science, Assistant, 医学系研究科, 助手 (80303288) ; TACHINO Katsuhiko Graduate School of Medical Science, Professor, 医学系研究科, 教授 (40092788)
• Project Period (FY): 2005 – 2006
• Keywords: Rehabilitation / animal / cell-tissue

Research Abstract

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.