Chinese Journal of Tissue Engineering Research ›› 2021, Vol. 25 ›› Issue (35): 5638-5643.doi: 10.12307/2021.293

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Effect of calorie restriction and its combined exercise on fat reduction and irisin expression in obese rats 

Bu Jianhua1, 2, Wang Zhen2, Liu Ziming3, Li Lin4, Yu Liang2   

  1. 1School of Physical Education, Qiqihar University, Qiqihar 161006, Heilongjiang Province, China; 2Beijing Sport University, Beijing 100084, China; 3Tennis Management Center of the General Administration of Sports of China, Beijing 100763, China; 4Jiuzhou Polytechnic, Xuzhou 221116, Jiangsu Province, China
  • Received:2021-01-30 Revised:2021-02-04 Accepted:2021-03-09 Online:2021-12-18 Published:2021-08-03
  • Contact: Yu Liang, MD, Associate professor, Doctoral supervisor, Beijing Sport University, Beijing 100084, China
  • About author:Bu Jianhua, Master, Lecturer, School of Physical Education, Qiqihar University, Qiqihar 161006, Heilongjiang Province, China; Beijing Sport University, Beijing 100084, China
  • Supported by:
    the National Natural Science Foundation of China, No. 31500964 (to YL)

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Abstract: BACKGROUND: Calorie restriction is a very effective way to reduce fat and weight, but it is unclear whether it is related to irisin.
OBJECTIVE: Using calorie restriction and its combined exercise as an intervention method, to establish a high-fat diet obese rat model to explore the possible fat-reducing mechanism of calorie restriction and its combined exercise via AMPKα-PGC-1α-FNDC5 pathway. 
METHODS: Sixty male Sprague-Dawley rats underwent an 8-week high-fat diet to establish an obesity model, 30 of which were randomly divided into continued high-fat diet group, calorie restriction group (70% of food intake during the modeling period was given daily), calorie restriction combined exercise group (70% of food intake during the modeling period was given daily, and aerobic treadmill exercise was performed, once a day, 6 days per week). All interventions were given for 4 weeks. Body mass and body fat content were recorded weekly, soleus muscle and fat wet weight were weighed, serum irisin level and the expression levels of peroxisome proliferator-activated receptor gamma coactivated 1α (PGC-1α), adenosine 5-monophosphate (AMP)-activated protein kinase α (AMPKα), p-AMPKα (Thr172), fibronectin type III domain containing protein 5 (FNDC5) in soleus muscle and p38 MAPK, and uncoupling protein 1 (UCP1) protein in adipose tissue were detected. An ethics approval was obtained from the Experimental Animal Ethics Committee of Beijing Sport University.
RESULTS AND CONCLUSION: Compared with continued high-fat diet group, body mass, body fat and wet weight of perinephric, epididymis, and scapular fat were significantly reduced in calorie restriction group and calorie restriction combined exercise group (P < 0.05). There was no significant difference in the wet weight of soleus muscle among groups (P > 0.05). Serum irisin level in the calorie restriction combined exercise group was higher than that in the continued high-fat diet group (P < 0.05). Compared with the continued high-fat diet group, the expression levels of PGC-1α, AMPKα, p-AMPKα (Thr172), FNDC5 protein in soleus muscle and p38 MAPK, UCP1 in adipose tissue were significantly higher in the calorie restriction group and calorie restriction combined exercise group (P < 0.05), especially in the calorie restriction combined exercise group. To conclude, a 4-week caloric restriction can effectively reduce body mass and body fat content; calorie restriction combined with exercise shows a better effect on fat reduction and upregulate the expression of FNDC5 in skeletal muscle via AMPKα-PGC-1α pathway. FNDC5 is cut into irisin and released into the blood to promote the browning of white fat through the p38 MAPK-UCP1 pathway, which improves the efficiency of lipolysis and energy supply and reduce body fat level in the body.

Key words: obesity, calorie restriction, exercise, fat reduction, irisin

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