흰쥐의 탈신경근 위축에 미치는 운동의 효과

Exercise Effects on the Atrophy of Denervated Muscles in Rat

The purpose of this study was to determine the effects of mild-intensity exercise training on the denervated muscle atrophy in the sciatic nerve injured rat. Thirty-six male Sprague-Dawley rats (250∼300 g) were randomly assigned into three groups; sham-denervated group (n=8), denervated group (n=8), and denervated-exercised group (n=20). Exercise consisted of treadmill running at 20 m/min speed with 0% grade of 30 min/day. the animals were decapitated at the second and sixth weeks postcrush. Soleus and medial gastrocnemius were immediately excised to be weighed. Type I and Ⅱ fibers of the muscles were differentiated by m-ATPase (pH 9.4) stain, and fiber diameters were evaluated. The results were as follows: 1) the weight of the soleus and medial gastrocnemius muscles showed a tendency to increase in both the denervation-exercised groups compared to the denervated groups. 2) In the 2-week denervation-exercised group, type Ⅱfiber diameter of soleus and type Ⅰfiber diameter of medial gastrocnemius were increased significantly compared to the denervated control group. 3) In the 6-week denervated-exercised group, type Ⅰ fiber diameter of soleus and type Ⅱ fiber diameter of medial gastrocnemius were hypertrophied significantly compared to sham-denervated group. The results of this study suggested that treadmill exercise partially prevented denervation atrophy in the soleus and medial gastrocnemius of the rat.