Effect of Regular Exercise during Recovery Period Following Steroid Treatment on the Atrophied Type II Muscles Induced by Steroid in Young Rats

Choe, Myoung Ae; Shin, Gi Soo; An, Gyeong Ju; Choi, Jung An; Lee, Yoon Kyong

Abstract

PURPOSE: This study was conducted to determine whether low intensity regular exercise following dexamethasone treatment could attenuate steroid-induced muscle atrophy. METHOD: 36 Wistar-rats(90-110g) were divided into six groups: control group(C), dexamethasone treatment group(D), sedentary group after normal sedentary period(C+S), sedentary group after dexamethasone treatment period(D+S), exercise group after normal sedentary period(C+E), and excercise group after dexamethasone treatment period(D+E). D, D+S, and D+E groups received dexamethasone injection(5mg/Kg) for seven days whereas C, C+S, and C+E groups received normal saline injection. Both C+E and D+E groups ran on a treadmill for 60 minutes/day(20minutes/4hours) at 15m/min and a 10degreegrade for seven recovery days. RESULT: Post-weight(body weight before muscle dissection) of D group significantly decreased by 16.03%, and that of D+E group significantly increased by 15.51% compared with pre-weight(body weight before steroid treatment). Type II muscle(plantaris and gastrocnemius) weights of D group were significantly lower than those of C group. Myofibrillar protein contents of type II muscles of D group tended to decrease comparing with C group. In D+E groups, body weights and relative weights of typeII muscles(muscle weight(mg)/post-weight(g)) tended to increase comparing with D+S group.
CONCLUSION
It is suggested that steroid- induced muscle atrophy can be ameliorated through low intensity regular exercise after dexamethasone treatment.