| Summary: | 碩士 === 臺北市立大學 === 運動科學研究所 === 104 === Purpose: The purpose of the study was to investigate the effect of endurance exercise training with or without protein-based supplementation on muscle mass and mitochondria enzyme activity in disuse skeletal muscle atrophy caused by hindlimb suspension (HS). Method: Thirty-two male Sprague-Dawley (SD) rats (230-280g) were weight-matched and assigned to the following 4 groups: Free control (FC), Hindlimb Suspension Placebo (H), Hindlimb Suspension + Exercise (HE), Hindlimb Suspension + Exercise+ Nutrition supplementation (HEN). After 10-days hindlimb suspension (HS) period, all rats were reloaded following one day of rest, thereafter endurance exercise procedure [treadmill running at a speed of 0.6 km/h to 1.2 km/h (+ 0.2 km/h per 3 days), 25 min/day (+ 5 min/3 days), 0% grade] and supplementation (10 ml/kg body wt of solution, containing 300 mg/kg body wt of leucine, 400 mg/kg of HMB, 400 mg/kg of whey protein, 200 mg/kg of casein, 600 mg/kg of glucose) were processed during the two-weeks reloading period. At the end of intervention, the soleus muscle mass and soleus cross-section area (CSA) were measured, and the intracellular level oxidative stress status, PGC-1α, 4-Hydroxynonenal, interleukin-6, and interleukin-10 protein were measured. Result: After two weeks of intervention, body weight, muscle mass and muscle fiber CSA in H, HE, and HEN groups could not be restored, and these parameters were still significantly lower than those of control group (p < 0.01). Endurance exercise training increased oxidative stress (TBARS) in HE and HEN (p < 0.05). PGC1-α protein level and mitochondria enzyme activity (CS) were greater in HE and HEN groups than FC and H groups (p < 0.05). Moreover, provision of protein supplementation during exercise training significantly induced a greater improvement in mitochondria enzyme activity (CS) in soleus muscle (p < 0.05). Conclusion: We demonstrated that two weeks of hindlimb suspension caused muscle atrophy, decreasing body weight, muscle mass, and muscle fiber cross-section area. However, although endurance exercise training and/or combined with protein supplementation could not full recover unused muscular structure but still shown the minor benefits of increasing mitochondria enzyme activity, which might improve muscular metabolic function.
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