High-intensity endurance exercise influences browning of white adipose tissue in a mouse model of high-fat diet induced obesity
Li Yujiao, Su Kunxia
Public Education Department of Zhongyuan Institute of Science and Technology, Zhengzhou 451400, Henan Province, China
Abstract: BACKGROUND: Studies have shown that uncoupling protein 1 (UCP-1), peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and fibronectin type III domain containing protein 5 (FNDC5) are the key proteins that influence the browning of white adipocytes. Endurance exercise can effectively reduce the body mass of mice, but there is no conclusion on the impact of high-intensity endurance exercise on the expression of UCP-1, PGC-1α, and FNDC5 proteins in white adipose tissue of obese mice induced by high-fat diet.
OBJECTIVE: To study the effects of high-intensity endurance exercise on the expression of UCP-1, PGC-1α and FNDC5 related to the browning of white adipocytes in mice with high-fat diet induced obesity.
METHODS: Four-week-old male C57BL/6J mice were fed normal diet for 1 week and then fed 8 weeks of high-fat diet to establish a mouse model of nutritional obesity. The control mice were fed normal diet. After 1 week of adaptive treadmill exercise, obese mice were subjected to high-intensity endurance treadmill exercise, while the control mice did not have exercise. After 8 weeks, epididymal and groin white adipose tissue of mice was separated and the fat mass changes were compared between groups. A portion of adipose tissue was taken for hematoxylin-eosin staining, and the remaining adipose tissue was used to detect the expression of UCP-1, PGC-1α, and FNDC5 that were related to the browning of white adipocytes by western blot and the expression changes were compared between groups.
RESULTS AND CONCLUSION: (1) High-fat diet could obviously increase the mass and cell volume of white adipose tissue in mice. (2) High-fat diet could remarkably reduce the expression of FNDC5 protein in white adipose tissue and slightly reduce the expression of UCP-1 and PGC-1α. However, there was no significant difference from the normal mice. (3) High-intensity endurance exercise could effectively reduce the mass and cell volume of white adipose tissue in mice with obesity induced by a high-fat diet. (4) High-intensity endurance exercise could considerably increase the expression of UCP-1, PGC-1α, and FNDC5 proteins in white adipose tissue, suggesting that high-intensity endurance exercise could remarkably promote the browning of white adipocytes in mice, thereby accelerating fat thermogenesis to achieve the purpose of reducing white adipose tissue.
Key words: endurance exercise, treadmill, high-intensity, obese mouse, white adipose tissue, brown adipose tissue, browning of white adipocyte, UCP-1 protein, PGC-1α protein, FNDC5 protein