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目的:观察急性大强度跑台运动及低频电刺激后大鼠骨骼肌及血清CAⅢ表达的变化,探讨CAⅢ与骨骼肌疲劳之间的关系。方法:36只雄性SD大鼠随机分为对照组、运动组和刺激组。运动组参照Bedford方案进行一次大强度跑台运动,造成大鼠运动性疲劳;刺激组采用低频电刺激的方法诱发大鼠腓肠肌疲劳。Western blot检测大鼠骨骼肌及血清CAⅢ的表达水平。结果:(1)与对照组相比,运动组大鼠比目鱼肌CAⅢ的表达水平明显降低(P<0.05),但趾长伸肌及血清CAⅢ的表达水平与对照组相比差异无统计学意义(P>0.05)。(2)随刺激时间的延长,大鼠腓肠肌的肌张力峰-峰(P-P)值逐渐降低,与刺激开始时相比,刺激10min即显著降低(P<0.05);而疲劳指数(FI)则随刺激时间的延长逐渐增加,刺激40min时FI高达52.14%左右。(3)与对照组相比,刺激组大鼠腓肠肌CAⅢ的表达水平显著降低(P<0.05),而比目鱼肌及趾长伸肌CAⅢ的表达水平虽均有下降,但差异无统计学意义(P>0.05)。结论:急性大强度跑台运动及低频电刺激诱发疲劳后均可引起相应骨骼肌CAⅢ表达下调(前者表现为比目鱼肌,后者为腓肠肌),表明骨骼肌疲劳的发生可能与其CAⅢ表达下调有关。
OBJECTIVE: To observe the changes of the expression of CAⅢ in skeletal muscle and serum after treadmill exercise and low-frequency electrical stimulation in acute high-intensity treadmill exercise, and to explore the relationship between CA Ⅲ and skeletal muscle fatigue. Methods: Thirty-six male SD rats were randomly divided into control group, exercise group and stimulation group. Exercise group reference Bedford program to conduct a large treadmill exercise, resulting in exercise-induced fatigue in rats; stimulation group using low-frequency electrical stimulation induced gastrocnemius fatigue in rats. Western blot was used to detect the expression of CA Ⅲ in skeletal muscle and serum of rats. Results: (1) Compared with the control group, the expression of CA Ⅲ in the soleus muscle of exercise group was significantly lower than that of the control group (P <0.05), but there was no significant difference in the expression level of CAⅢ between the extensor digitorum longus and the serum CA Ⅲ (P> 0.05). (2) The peak-peak (PP) value of gastrocnemius decreased gradually with the time of stimulation, and decreased significantly (P <0.05) 10 min after stimulus, while the fatigue index With the extension of stimulation time gradually increased, 40min stimulated FI up to 52.14%. (3) Compared with the control group, CA Ⅲ expression in the gastrocnemius muscle of the rats in the stimulation group was significantly decreased (P <0.05), while the expression level of CA Ⅲ in the soleus muscle and the extensor digitorum longus was decreased, but the difference was not statistically significant P> 0.05). CONCLUSION: Acute high-intensity treadmill exercise and fatigue induced by low-frequency electrical stimulation can all induce the down-regulation of CAⅢ expression in the corresponding skeletal muscle (the former shows soleus muscle and the latter gastrocnemius muscle), indicating that the occurrence of skeletal muscle fatigue may be related to the down-regulation of CA Ⅲ expression.