Wang Zhen, Yu Liang, Fu Yue
School of Sport Science, Beijing Sport University, Beijing 100084, China.
Zhongguo Ying Yong Sheng Li Xue Za Zhi. 2020 Jul;36(4):289-295. doi: 10.12047/j.cjap.5942.2020.063.
To observe the effect of weight control of intermittent fasting in different time course (14 d, 28 d)and explore its effect on skeletal muscle mass and autophagy.
Sixty SD rats (male) were randomly divided into sedentary group (Sed), intermittent fasting group (InF) and exercise group (Exe), 20 rats of each group, intervention duration is 14 d and 28 d. Animals of InF group were fasted every other day, animals of Exe group underwent aerobic exercise on treadmill, the weight was recorded every week. The body fat mass was recorded by DEXA and then the fat mass index was calculated. The wet weight of bilateral soleus muscle was weighed and wet weight index was calculated. Immunofluorescence was used to detect laminin and light chain 3 (LC3), which reflect muscle fiber cross-sectional area and autophagosome respectively. Transmission electron microscopy was used to observe the number and morphology of autophagosomes. The expression levels of autophagy related proteins Unc-51 like kinase 1 (ULK1), LC3, sequestosome1 protein (p62), AMP activated protein kinase (AMPKα) and p-AMPKα (Thr172) were detected by Western blot.
① From the 7th day of intervention, the body weight of rats in InF and Exe groups was significantly lower than that in Sed group, and the body weight of InF group was significantly lower than that in Exe group (＜0.01). After 28 days of intervention, the fat mass index in InF and Exe groups was significantly lower than that in Sed group, the fat mass index of InF group was significantly lower than that in Exe group (＜0.05).② After 28 days of intervention, the cross-sectional of muscle fibers in Exe group was significantly larger than that in Sed and InF groups (＜0.01). ③The expressions of AMPKα, p-AMPKα (Thr172) and ULK1 in InF and Exe groups were significantly higher than those in Sed group (＜0.05). However, at 14 days, only InF group showed the increase of LC3-II/LC3-I ratio and the decrease of p62 level (＜0.05). The same indicators of Exe group were only significant changed at 28 d.
① Intermittent fasting is superior to exercise in controlling the growth of body weight and body fat in rats. ② In terms of skeletal muscle autophagy activation, the length of intervention required for intermittent fasting (14 days) is shorter than aerobic exercise (28 days).
观察不同时程（14天、28天）间歇性禁食体重控制效果，探讨其对骨骼肌质量及自噬的影响。
将60只雄性SD大鼠随机分为安静组（Sed）、间歇性禁食组（InF）和运动组（Exe），每组20只，干预时长为14天和28天。InF组动物隔日禁食，Exe组动物在跑步机上进行有氧运动，每周记录体重。采用双能X线吸收法（DEXA）记录体脂质量并计算脂肪质量指数。称量双侧比目鱼肌湿重并计算湿重指数。采用免疫荧光法检测分别反映肌纤维横截面积和自噬体的层粘连蛋白和轻链3（LC3）。采用透射电子显微镜观察自噬体的数量和形态。采用蛋白质免疫印迹法检测自噬相关蛋白Unc-51样激酶1（ULK1）、LC3、聚集体蛋白1（p62）、腺苷酸活化蛋白激酶（AMPKα）和磷酸化AMPKα（Thr172）的表达水平。
①干预第7天起，InF组和Exe组大鼠体重显著低于Sed组，且InF组大鼠体重显著低于Exe组（P＜0.01）。干预28天后，InF组和Exe组脂肪质量指数显著低于Sed组，InF组脂肪质量指数显著低于Exe组（P＜0.05）。②干预28天后，Exe组肌纤维横截面积显著大于Sed组和InF组（P＜0.01）。③InF组和Exe组AMPKα、磷酸化AMPKα（Thr172）和ULK1的表达水平显著高于Sed组（P＜0.05）。然而，在14天时，仅InF组LC3-II/LC3-I比值升高且p62水平降低（P＜0.05）。Exe组相同指标仅在28天时显著变化。
①间歇性禁食在控制大鼠体重和体脂增长方面优于运动。②在激活骨骼肌自噬方面，间歇性禁食所需干预时长（14天）短于有氧运动（28天）。
