Wheat Bran Protein Improves Lipid Metabolism by Downregulating the Amount of HMG-CoA Reductase in the Liver of High-Fat Diet-Fed Rats

Abstract

Background. The hypolipidemic effects of wheat bran have been widely documented; however, limited research has concurrently revealed the hypolipidemic and antioxidant properties of wheat bran protein (WBP). Objective. This study investigates the impact of WBP (5% daily dietary intake) on antioxidant activity, cholesterol metabolism, and serum/hepatic lipids in high-fat diet-fed rats. Methodology. In our animal experiment, we used 12 male Wistar rats that were 4 weeks old. Biochemical indicators of fecal, serum, intestinal, and liver were tested by kits or chemical techniques. The experiment on cholesterol micellar solubility was also carried out in vitro. Results. After 28 days of feeding, the results revealed that WBP significantly reduced the levels of total cholesterol ($P<0.05$) in serum and liver, the levels of triglycerides ($P<0.05$), the levels of MDA ($P<0.05$), and the levels of very low-density lipoprotein and low-density lipoprotein ($P<0.05$), and significantly increased the levels of high-density lipoprotein ($P<0.05$), the levels of glutathione peroxidase, and the level of total antioxidant capability. By downregulating the level of sterol regulatory element-binding protein-2 ($P<0.05$), WBP also reduced the content of 3-hydroxy-3-methylglutaryl-coenzyme A ($P<0.05$). Conclusion. In vivo, WBP demonstrated a substantial hypolipidemic and antioxidant impact ($P<0.05$), while in vitro, it significantly decreased the micellar solubility of cholesterol ($P<0.001$).