Objective: The effects of Alternate-day modified fasting combined exercise on fat mass, muscle mass, and serum Irisin, FNDC5 and UCP1 proteins were investigated in rats with 4 weeks of aerobic exercise and modified alternate-day fasting intervention.
Methods: Thirty-two healthy 8-week-old SPF male SD rats were randomly divided into control group, exercise group, alternate-day modified fasting and alternate-day modified fasting combined with exercise group, 8 rats in each group. The exercise group performed treadmill exercise with moderate exercise intensity(60 min/d,5 d/w), the alternate-day modified fasting group alternated between fasting and free feeding every other day, and fed 25% basal energy feed on fasting days, and the alternate-day modified fasting combined exercise group received two combined interventions. After 4 weeks of intervention, the body fat rate of rats was measured by apical blood sampling and abdominal aortic blood sampling, and the serum was preserved and centrifuged, and the wet weights of bilateral gastrocnemius, bilateral perirenal fat and brown fat at the scapula were weighed, and samples were collected for paraffin sectioning and HE staining, and the cell areas were counted; serum Irisin levels were measured by ELISA, and FNDC5 protein expression in gastrocnemius and UCP1 protein expression in adipose tissue were detected by Western blot.
Results: After 4 weeks of intervention, compared with the Con group, energy intake, body weight and body fat were decreased significantly in the Exer, ADMF and ADMF-Exer groups (P＜0.05), the wet weight/body weight and adipocyte area of white fat were reduced significantly (P＜0.01), and there was no significant difference in scapular fat wet weight/body weight (P＞0.05). Compared with the Con group, the gastrocnemius wet weight/body weight in the ADMF group was reduced significantly (P＜0.05), while that in the ADMF-Exer group was increased significantly (P＜0.05), the muscle cross-sectional areas in the Exer group and the ADMF-Exer group were increased (P＜0.05), and the content of gastrocnemius FNDC5 protein, serum Irisin level and expression of adipose UCP1 protein in the ADMF-Exer group were increased significantly (P＜0.05). After 4 weeks of intervention, energy intake was reduced significantly in both ADMF and ADMF-Exer groups (P＜0.01) and body weight of ADMF-Exer group was decreased (P＜0.05) compared with the Exer group. Compared with the Exer group, there were no significant differences in body fat content, white fat wet weight/body weight and scapular fat wet weight/body weight between ADMF group and ADMF-Exer group (P＞0.05), and adipocyte area in ADMF-Exer group was reduced significantly (P＜0.05). Compared with the Exer group, the gastrocnemius muscle wet weight/body weight was reduced significantly in the ADMF group (P＜0.05), and the expression of FNDC5 protein, serum Irisin and adipose UCP1 protein in the ADMF-Exer group were increased significantly compared with the Exer group (P＜0.05).
Conclusion: Alternate-day modified fasting combined with exercise intervention can effectively control body weight and reduce body fat in rats, and the mechanism may be through the FNDC5/Irisin-UCP1 pathway to induce browning of white adipose tissue and increase thermogenesis of brown fat.
目的: 探究改良隔日禁食联合运动对大鼠脂肪量、肌肉量的影响以及对血清鸢尾素(Irisin)、FNDC5和UCP1蛋白的变化。方法: 选取32只健康的8周龄SPF级雄性SD大鼠,随机分为对照组(Con,8只)、运动组(Exer,8只)、改良隔日禁食组(ADMF,8只)和改良隔日禁食联合运动组(ADMF-Exer,8只),Exer组进行中等运动强度跑台运动(60 min/d,5日/周),ADMF组部分禁食和自由摄食隔天交替进行,禁食日给予25%基础能量的饲料,ADMF-Exer组进行两种联合干预,称量记录大鼠每日进食量,每周测量大鼠体重。干预4周后检测大鼠体脂率,心尖取血和腹主动脉取血致死,保留并离心血清,称量大鼠双侧腓肠肌、双侧肾周脂肪和肩胛处棕色脂肪湿重,并取样制作石蜡切片和进行HE染色,统计细胞面积;用ELISA检测血清Irisin水平,Western blot实验检测腓肠肌中FNDC5蛋白表达,脂肪组织中UCP1蛋白表达。结果: 4周干预后,与Con组相比,Exer组、ADMF组和ADMF-Exer组三个组的能量摄入、体重和体脂都明显降低(P＜0.05),白色脂肪湿重/体重和脂肪细胞面积显著减少(P＜0.01),肩胛脂肪湿重/体重无显著差异(P＞0.05),与Con组相比,ADMF组腓肠肌湿重/体重明显减少(P＜0.05),ADMF-Exer组明显增多(P＜0.05),Exer组和ADMF-Exer组肌肉横截面积增大(P＜0.05),ADMF-Exer组的腓肠肌FNDC5蛋白含量、血清Irisin水平和脂肪UCP1蛋白表达都显著升高(P＜0.05);4周干预后,与Exer组相比,ADMF组和ADMF-Exer组能量摄入都明显降低(P＜0.01),ADMF-Exer组体重明显降低(P＜0.05),与Exer组相比,ADMF组和ADMF-Exer组体脂含量、白色脂肪湿重/体重和肩胛脂肪湿重/体重无显著性差异(P＞0.05),ADMF-Exer组脂肪细胞面积显著减小(P＜0.05),与Exer组相比,ADMF组腓肠肌湿重/体重显著降低(P＜0.05),与Exer组相比,ADMF-Exer组FNDC5蛋白含量、血清Irisin和脂肪UCP1蛋白表达都显著升高(P＜0.05)。结论: 改良隔日禁食联合运动干预可有效控制大鼠的体重、减少体脂,其机制可能是通过FNDC5/Irisin- UCP1通路,诱导白色脂肪组织棕色化和增加棕色脂肪产热作用。.
Keywords: Irisin; alternate-day modified fasting; exercise; lose fat; rats.