Muscle composition after 14-day hindlimb unloading in rats: effects of two herbal compounds.
OBJECTIVE
We studied the potential of two herbal compounds (HC-1 and HC-2) in different dosages (HC-1, containing ligustrazine; HC-2, containing radix astragali) as a countermeasure against muscle atrophy in a hindlimb unloading rat model. Soleus muscle weight, fiber type distribution, cross-sectional area (CSA), and myosin ATPase activity were measured.


METHODS
Six rats each were assigned to a nine-group design: Control (CON); hindlimb unloading only (HLU); hindlimb unloading plus intragastric water instillation (HLU-W); and hindlimb unloading plus different dosages of instilled HC-1 (HLU-HC-1l, HLU-HC-1m, HLU-HC-1h) or HC-2 (HLU-HC-2l, HLU-HC-2m, HLU-HC-2h).


RESULTS
As expected, in HLU and HLU-W, soleus muscle-to-body weight ratio and CSA of type I and II fiber went down, and myosin ATPase activity and the percentage of type II fibers went up, all compared with CON. Compared to untreated rats, high-dose HC-1 enhanced type I and II fiber CSA by 77% and 55%, respectively; myosin ATPase activity (type II fiber percentage) were lower, but soleus muscle-to-body weight ratio did not change. High-dose HC-2 enhanced soleus muscle-to-body weight ratio by 33%; and type I / type II fiber CSA by 143% and 83% above HLU-W values, respectively, and resulted in a slower myosin ATPase activity (corresponding to a lower type II fiber percentage). Low- to mid-dose HC-1 and HC-2 showed some preventive effects as well.


CONCLUSIONS
HC-1 and HC-2 in proper dosages diminished muscle atrophy that otherwise occurs in simulated weightlessness.
Zhang
Haixiang
H
College of Life Sciences, Northwest University, Xi'an, China.
He
Zhixian
Z
Gao
Yunfang
Y
Hinghofer-Szalkay
Helmut G
HG
Fan
Xiaoli
X
D000704:Analysis of Variance; D000818:Animals; D027885:Astragalus propinquus; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005260:Female; D019417:Hindlimb Suspension; D018482:Muscle, Skeletal / Q000187:drug effects*; D009133:Muscular Atrophy / Q000517:prevention & control*; D009218:Myosins / Q000032:analysis; D011719:Pyrazines / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D018474:Weightlessness Simulation
D004365:Drugs, Chinese Herbal; D011719:Pyrazines; C027492:Huang Qi; D009218:Myosins; C017953:tetramethylpyrazine