Expression of the key metabolic regulators in the white adipose tissue of rats; the role of high-fat diet and aerobic training

摘要

Lipid metabolism, especially in the white adipose tissue as an active metabolic organ, is tightly regulated by the key transcription factors, such as the sterol regulatory element binding protein lc (SREBP-lc) and the Farnesoid X Receptor (FXR). We havestudied the expression of these genes in the white adipose tissue to see how a high fat diet (HFD) and two intensities of aerobic training change the lipogenic and lipolytic pathways. 44 male Wistar rats randomly divided into the normal (12% calories from fat) and HFD (56% calories from fat) groups. Each group included control (n=6), moderate trained (n=8, -65% Vo_(2max)) and high intensity trained (n=8, -75% Vo_(2max)) rats. After 8 weeks of training, the weight changes, plasma insulin and lipid profile levels and the relative gene expression of SREBP-lc and FXR in the adipose tissue was measured. Data were analysed by 2-way ANOVA (P<0.05). HFD fed rats showed higher levels of insulin and dyslipidemia that was correlated with the higher weight gain. Also, the adipose expression of SREBP-lc was higher in the HFD fed rats that it was strongly correlated with the lower FXR expression. Trained rats independent of the intensity of the training showed lower SREBP-lc and higher FXR expression, but no changewas observed in the lipid profile levels. HFD-induced dyslipidemia could occur via SREBP-lc activation in the adipose tissue while the aerobic training activates FXR and inhibits the lipogenic pathways. Despite the activation of lipolytic pathways in the trained rats, it seems that diet has more effect on the lipid profile than the aerobic training.