posted on 2021-07-21, 10:29authored byJinxin Liu, Yu Wang, Lamei Xue, Chenzhipeng Nie, Juan Sun, Mingcong Fan, Haifeng Qian, Li Wang, Yan Li
Hypercholesterolemia
is a major
risk factor for chronic metabolic diseases. Nevertheless, a whole-grain
diet could ameliorate this issue in a number of ways, including by
regulating bile acid metabolism. However, the potential mechanism
is unclear. The aim of the current study is to explore the effects
of whole-grain diets (brown rice diet and whole wheat diet) on bile
acid homeostasis. After intervention for 8 weeks in mouse model, whole-grain
diets showed reduced feed conversion ratio, and the lipid levels (total
cholesterol (TC) and triglycerides (TG)) were also meliorated in the
serum and liver of mice. Moreover, whole-grain diets reduced the expression
of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) (cholesterol synthesis)
in the liver of mice. Interestingly, whole-grain diets not only promoted
the mRNA expressions of low-density lipoprotein receptor (LDLR), ATP
binding cassette transporter G1 (ABCG1), and scavenger receptor class
B type I (SR-BI) (reverse cholesterol transport) but also facilitated
the expressions of cytochrome P450, family 7, subfamily a, polypeptide
1 (CYP7a1) and cytochrome P450, family 27, subfamily a, polypeptide
1 (CYP27a1) (bile acid synthesis). Further study found that whole-grain
diets promoted intestinal bile acid reabsorption and reduced bile
acid excretion. Our study provided a novel metabolic regulation of
bile acids in response to reduced cholesterol levels induced by whole-grain
diets.