Effects of Four-week Intermittent Fasting on Skeletal Muscle Mass and Autophagy in Rats / 中国运动医学杂志

ABSTRACT

Objective To observe the changes of body weight,fat mass and skeletal muscle mass of rats after 4 weeks of intermittent fasting,and explore relationship with autophagy in skeletal muscle,so as to provide theoretical basis for intermittent fasting.Method Twenty male Sprague Dawley rats were randomly divided into a control group (Con) and an intermittent fasting group (IF),each of 10.The rats of IF group were forbidden to eat food every Wednesday and Friday,and the body weight of both groups was recorded weekly.After 4 weeks,Dual-Energy X-Ray Absorption (DEXA) was used to analyze the body fat mass,then the bilateral soleus was separated to record the wet weight and measure the cross-sectional area of the soleus fibers by testing laminin with immunofluorescence confocal laser scanning microscope.The form of autophagic vacuole of soleus was observed using a transmission electron microscopy.The expression of autophagy-related protein LC3,p62 and regulating protein AMPK,pAMPK and ULK1 were measured using Western blotting.Result After 4 weeks of intermittent fasting,the weight and fat mass of IF were significantly lower than those of Con (P＜0.01),but there were no significant differences between them in wet weight and cross-sectional area of soleus (P＞0.05).The expressions of AMPK,p-AMPK,ULK1 in IF were significantly higher than those in Con (P＜0.01).Compared with Con,the expression of LC3-Ⅱ/LC3-Ⅰ of IF increased significantly,while the expression of p62 decreased significantly (P＜0.01).Conclusion Four weeks of intermittent fasting decreases the fat mass significantly,and control the weight efficiently.Intermittent fasting can maintain the skeletal muscle mass by promoting moderate autophagy through the AMPK-ULK1 pathway.It should be a potential lose weight method for further research.