Effects of Resistance Exercise and Fermented Soybean Intake on Protein Expression Markers Related to Browning of White Adipose Tissue in Diet-induced Obese Rats

PURPOSE This study aimed to analyze the combined treatment effect of fermented soybean intake (for additional protein intake) and resistance exercise (for muscle metabolism activation) on the molecular biological response index of white adipose tissue (WAT) browning. METHODS The study included twenty 50-week-old male Wistar rats, who were made obese by being fed a high-fat diet for 8 weeks and then were randomly divided into four groups, control (Con), fermented soybean intake (Soy), resistance exercise (RT), and fermented soybean intake and resistance exercise combination (Soy+RT). After 12 weeks of Soy and RT treatment, body composition, and protein expression patterns such as peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α), fibronectin type III domain-containing protein 5 (FNDC5), interleukin-6 (IL-6), and uncoupling protein-1 (UCP1) were compared in extensor digitorum longus and retroperitoneal fat. RESULTS The obese rats demonstrated a reduction in body weight and body fat mass, as well as maintenance of lean mass. Interestingly, the groups treated with Soy, RT, and Soy+RT displayed enhanced protein expression of PGC-1α, FNDC5, UCP1, and IL-6 in the extensor digitorum longus and retroperitoneal fat tissue than Con. In particular, the Soy+RT group displayed the most remarkable activation of the aforementioned protein levels in the muscle and adipose tissues. CONCLUSION This study concluded that resistance exercise and fermented soybean intake can partly contribute to the browning of WAT.