Synergistic Effects of the Aerobic Training and Capsaicin on the Expression level of AMP-Activated Protein Kinase and Protein Kinase B Gene of Liver Tissue in Rat Fed a High-Fat Diet

Background & objectives: Obesity and a high-fat diet (HFD) lead to metabolic disorders in the liver by affecting the signaling pathways of fat and glucose metabolism. Exercise and dietary habits are of special interest to prevent and counteract obesity and its associated metabolic disorders. Also, Capsaicin ameliorates diet-induced obesity in rodents and humans. The aim of the present study was to examine the effect of aerobic exercise and capsaicin on the gene expression level of AMP-activated protein kinase (AMPK) and protein kinase B (Akt) in the liver of HFD rats. Methods: in this experimental study, 40 male Wistar rats were fed a normal diet (ND, n=8) or high-fat diet (HFD) (n=32) for 8 weeks. After 8 weeks, all rats were divided into 5 groups: normal diet (ND), high-fat diet (HFD), high-fat diet-training (HFDT), high-fat diet-capsaicin (HFDCap), high-fat diet-training-capsaicin (HFDTCap). Training groups have performed a moderate- intensity aerobic running program (60-50% VO2max, at 15-25 m/min, 30-60 min/day, and 5 days/week) on a motor-driven treadmill for eight weeks. Capsaicin (4 mg/kg/day) was administered orally, by gavage, once a day. Results: Induction of diabetes was associated with decreased AMPK expression ( p =0.0001) and increased Akt ( p =0.0001). The results showed that training and capsaicin significantly increased AMPK expression ( p =0.032 and p =0.045, respectively) and decreased Akt expression ( p =0.045 and p =0.049, respectively) in HFD rat hepatocytes. Also, the interaction of training and capsaicin had a significant effect on the expression of AMPK ( p =0.017) and Akt ( p =0.0001). Conclusion: The results showed that HFD impaired hepatocyte function and that aerobic exercise and capsaicin increased lipogenesis with increasing AMPK and decreasing Akt expression. However, the interaction effect of training with capsaicin was greater.