RESUMO
<p><b>AIM</b>To study the effect of radix-astragali compound(RC) on muscle atrophy in tail-suspended rats. Muscle weight, fiber type distribution, cross-sectional area (CSA), and activity of myosin adenosine triphosphatase (ATPase) in rat soleus muscle were investigated.</p><p><b>METHODS</b>The tail-suspended rats were subjected to a 14 days simulated weightlessness, during which period, RC or saltwater was given via intragastric instillation during tail suspension. The changes of soleus muscle weight were scaled by muscle-to-body weight ratio. The activities of myosin ATPase of muscle fibers were detected by method of Ca(2+) -ATPase.</p><p><b>RESULTS</b>After a 14 days tail suspension it was found: in rats treated with RC, soleus muscle-to-body weight ratio rose by 33.33% (P < 0.01), both CSA of type I and II fiber drastically enhanced by(143.03%, P < 0.01; 83.25%, P < 0.01), the percentage of type I fiber significantly declined compared to the untreated rats.</p><p><b>CONCLUSION</b>RC is able to effectively prevent muscle atrophy caused by tail suspension and restrain the increase in the myosin ATPase activities caused by simulated weightlessness.</p>