Conclusions
SY could reduce fat mass, decrease glucose levels and improve insulin sensitivity in high-fat diet-induced obese mice. The probable mechanism is to increase PPARγ2 expression by stimulating PPARγ2 promoter activities, further increasing the expression of insulin signaling pathway-related genes in subcutaneous adipose tissue.
Methods
High-fat diet-induced obese mice were given 120 mg/kg/day SY for 8 weeks. Glucose and insulin tolerance tests were carried out. Fat mass and serum levels of glucose and insulin were measured. The expression of insulin signaling pathway-related genes and PPARγ2 in the adipose tissue was measured. In vitro, the effects of SY (0-500 mg/L) and hydroxysafflor yellow A (0-100 mg/L) on PPARγ2 promoter activities and PPARγ2 messenger ribonucleic acid (mRNA) levels in 3T3-L1 preadipocytes or adipocytes were also detected.
Results
Safflower yellow reduced fat mass, decreased glucose levels and improved insulin sensitivity in obese mice. SY also increased the mRNA levels of insulin signaling pathway-related genes, and increased PPARγ2 mRNA levels by 39.1% in subcutaneous adipose tissue (P < 0.05). In vitro, SY and hydroxysafflor yellow A significantly enhanced PPARγ2 promoter activities by 1.3-2.1-fold, and increased PPARγ2 mRNA levels by 1.2-1.6-fold in 3T3-L1 preadipocytes or adipocytes (P < 0.05). Conclusions: SY could reduce fat mass, decrease glucose levels and improve insulin sensitivity in high-fat diet-induced obese mice. The probable mechanism is to increase PPARγ2 expression by stimulating PPARγ2 promoter activities, further increasing the expression of insulin signaling pathway-related genes in subcutaneous adipose tissue.