AIMTo 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.

METHODSThe 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.

RESULTSAfter 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.

CONCLUSIONRC is able to effectively prevent muscle atrophy caused by tail suspension and restrain the increase in the myosin ATPase activities caused by simulated weightlessness.

Animals ; Drugs, Chinese Herbal ; pharmacology ; Hindlimb Suspension ; Male ; Muscle Fibers, Skeletal ; enzymology ; Muscle, Skeletal ; drug effects ; enzymology ; Muscular Atrophy ; prevention & control ; Myosins ; metabolism ; Rats ; Rats, Sprague-Dawley ; Weightlessness Simulation ; methods