Lactoferrin Alleviates the Progression of Atherosclerosis in ApoE-/- Mice Fed with High-Fat/Cholesterol Diet Through Cholesterol Homeostasis.

Abstract

Lactoferrin (LF) is a multifunctional glycoprotein and has beneficial effects on the regulation of lipid metabolism. However, whether LF supplementation alleviates the development of atherosclerosis (AS) remains unclear. In the present study, all of 48 male Apolipoprotein E-/- mice were fed with high-fat diet with 1.25% added cholesterol and divided to four treatment groups with either distilled water (HFCD), LF solutions at 2\u2009mg/mL (low LF), 10\u2009mg/mL (middle LF or MLF), or 20\u2009mg/mL (high LF or HLF) for 12 weeks. Oral glucose tolerance tests (OGTT) were performed at weeks 0, 4, 8, and 12. At the end of the experiment, lipids in serum, liver, and feces were determined. The livers, whole aortas, and aortic sinuses were pathologically examined. The protein expression of factors related to cholesterol synthesis, absorption, and excretion were detected through western blot. No significant difference in body weight, food intake, and OGTT was observed among the four groups. Compared with the HFCD group, the MLF and HLF groups had significantly decreased serum and hepatic cholesterol levels and significantly increased fecal cholesterol contents. LF alleviated the hepatic steatosis and lipid droplet, especially in the MLF group. LF also significantly decreased the average lesion areas in the whole aorta, especially in the MLF group. On the other hand, LF downregulated hepatic protein expression of HMG-CoA reductase (the rate-limiting enzyme in cholesterol synthesis) and upregulated cholesterol 7-alpha hydroxylase (the rate-limiting enzyme in bile acid synthesis from cholesterol). LF also downregulated the intestinal expression of Niemann-Pick C1-like 1 protein, which is known to bind to a critical mediator of cholesterol absorption. In conclusion, LF supplementation alleviates the AS in mice on HFCD likely by reducing the synthesis and absorption of cholesterol and increasing cholesterol excretion.