This study was conducted to determine whether low intensity regular exercise following steroid treatment could attenuate steroid-induced muscle atrophy. Thirty-eight Sprague-Dawley rats weighing 165~175g were divided into six groups ; control group(C), dexamethasone administration group(D), sedentary after normal saline administration group(C+Se), exercise after normal saline administration group(C+Ex), sedentary group after dexamethasone administration(D+Se), exercise group after dexamethasone administration(D+Ex). Either dexamethasone(5mg/kg) or normal saline was injected for 7days accordingly. Exercise was started at 10m/min on the 10° grade treadmill and gradually increased up to 15m/min by the 7th day for 60minutes/day(20min×3). The data were analyzed by Kruskal-Wallis test and Mann-Whitney U test using the SPSS WIN 9.0 program.
Body weight, muscle weight and myofibrillar protein content of both plantaris and gastrocnemius, Type Ⅰ, Ⅱ muscle fiber cross-sectional area of plantaris, and Type Ⅱ muscle fiber cross-sectional area of gastrocnemis in D group were significantly lower than those of C group(p<.05) respectively. Hindlimb muscle weight, myofibrillar protein content of both plantaris and gastrocnemius, Type Ⅰ muscle fiber cross-sectional area of soleus and Type Ⅰ, Ⅱ muscle fiber cross-sectional area of plantaris in D+Ex group tended to increase compared to those of D+Se group. Myofibrillar protein content of both plantaris and gastrocnemius, Type Ⅰ muscle fiber cross-sectional area of plantaris in D+Ex group tended to increase compared to those of C+Se group.
Based on these results, it is suggested that regular low-intensity exercise during recovery period after steroid treatment might facilitate the recovery from steroid-induced muscle atrophy.