Effects of β-glucan Rich Barley Flour on Glucose and Lipid Metabolism in the Ileum, Liver, and Adipose Tissues of High-Fat Diet Induced-Obesity Model Male Mice Analyzed by DNA Microarray

Abstract

We evaluated whether intake of β-glucan-rich barley flour affects expression levels of genes related to glucose and lipid metabolism in the ileum, liver, and adipose tissues of mice fed a high-fat diet. C57BL/6J male mice were fed a high-fat diet supplemented with high β-glucan barley, for 92 days. We measured the expression levels of genes involved in glucose and lipid metabolism in the ileum, liver, and adipose tissues using DNA microarray and q-PCR. The concentration of short-chain fatty acids (SCFAs) in the cecum was analyzed by GC/MS. The metabolic syndrome indices were improved by barley flour intake. Microarray analysis showed that the expression of genes related to steroid synthesis was consistently decreased in the liver and adipose tissues. The expression of genes involved in glucose metabolism did not change in these organs. In liver, a negative correlation was showed between some SCFAs and the expression levels of mRNA related to lipid synthesis and degradation. Barley flour affects lipid metabolism at the gene expression levels in both liver and adipose tissues. We suggest that SCFAs are associated with changes in the expression levels of genes related to lipid metabolism in the liver and adipose tissues, which affect lipid accumulation.

High β-Glucan Barley Supplementation Improves Glucose Tolerance by Increasing GLP-1 Secretion in Diet-Induced Obesity Mice

“…These results, together with those from our previous report [ 25 ], suggest that augmentation in the number of L cells and the subsequent elevation in the level of GLP-1 were induced by production of SCFAs. Thus, a new mechanism for increasing GLP-1 secretion by HGB intake is proposed.…”

“…Our previous report showed that barley intake increased the biosynthesis of short-chain fatty acids (SCFAs) by the gut microbiota, but we did not measure gut hormone levels [ 25 ]. Given that high β-glucan barley stimulates SCFA production, we hypothesized that a high β-glucan barley diet might result in greater GLP-1 secretion by comparison to a cellulose based diet.…”

Ingestion of High β-Glucan Barley Flour Enhances the Intestinal Immune System of Diet-Induced Obese Mice by Prebiotic Effects

“…First, we used previously determined DNA microarray data of the ileum [ 28 ] to establish how HGB flour intake affects gene expression related to the immune system in the high-fat diets. KEGG enrichment analysis of DEGs suggested that HGB flour altered gene expression involved in several metabolic pathways of the ileum.…”

“…The procedure was also performed for mice fed a diet not supplemented with β-glucan rich barley flour as a control (supplemented with cellulose). We identified differentially expressed genes (DEGs) using cut-off criteria (Log-ratio > 1.3 fold and < 0.77 fold in the barley group compared with the control group) based on our previous study [ 28 ]. Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed using the DAVID database (accessed on 12 December 2020).…”

“…Here, we focused on the gut fermentability of barley flour and confirmed its effect on the innate immune response under high-fat conditions. Firstly, we investigated gene expression to clarify whether the intake of barley affects the immune system in the ileum using previously published DNA microarray data [ 28 ]. Next, as the main aim of this study, we investigated whether or not IgA secretion and mRNA expression levels of cytokines change following the ingestion of high β-glucan barley (HGB) flour in diet-induced obese mice.…”