[Effects of exercise before steroid treatment on type i and type ii hindlimb muscles in a rat model].
OBJECTIVE
The purpose of this study was to examine the effects of daily exercise before steroid treatment on mass, the type I and II fiber cross-sectional area, and myofibrillar protein content of hindlimb muscles in a rat model.


METHODS
Adult male Sprague-Dawley rats were randomly assigned to one of three groups: a control group(n=10) that had a normal saline injection for 7 days, a steroid group(n=10) that had a steroid injection for 7 days, and an exercise-steroid group(n=10) that ran on the treadmill for 7 days before a steroid treatment. Body weight and food intake were measured every day. At 15 days all rats were anesthetized and the soleus, plantaris and gastrocnemius muscles were dissected.


RESULTS
The exercise-steroid group showed significant increases as compared with the steroid group in body weight, muscle weight of the soleus and gastrocnemius, type II muscle fiber cross-sectional area of plantaris, and myofibrillar protein content of the soleus, plantaris, and gastrocnemius. As compared with the control group, the steroid group showed significant decreases in body weight and diet intake, muscle weight, the type II fiber cross-sectional area and myofibrillar protein content of the soleus, plantaris, and gastrocnemius muscles.


CONCLUSIONS
Daily exercise before steroid treatment attenuates hindlimb muscle atrophy, with type II muscle changes more apparent than type I muscle changes.
Choe
Myoung-Ae
MA
College of Nursing, Seoul National University, Seoul, Korea. machoe@snu.ac.kr
An
Gyeong Ju
GJ
D000818:Animals; D001835:Body Weight; D003131:Combined Modality Therapy; D003907:Dexamethasone / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005081:Exercise Therapy; D006614:Hindlimb; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D018485:Muscle Fibers, Skeletal / Q000187:drug effects* / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000502:physiology; D009133:Muscular Atrophy / Q000209:etiology / Q000473:pathology / Q000628:therapy*; D009929:Organ Size; D051381:Rats; D017207:Rats, Sprague-Dawley
D003907:Dexamethasone