Project description:To determine the effect of consumption of a quercetin-rich diet on obesity and dysregulated hepatic gene expression, C56BL/6J mice were fed for 20 weeks on control or a Western diet high in fat, cholesterol and sucrose, both with or without 0.05% quercetin. Chronic dietary intake of quercetin reduced body weight gain and visceral and liver fat accumulation, and improved hyperglyceamia, hyperinsulinaemia, dyslipidaemia in mice fed a Western-style diet. Feeding a Western-style diet altered expression of genes related to inflammatory responses, lipid metabolism and oxidative phosphorylation in C57BL/6J mice after 20 weeks. The results from exhaustive gene expression analysis showed that quercetin minimally influenced hepatic gene expression in mice fed the Western diet. The gene screening results (GSEA) were consistent with the notion that it did improve mitochondrial function to some extent. Quantitative RT-PCR analysis indicated that quercetin did influence important regulators of fat accumulation and metabolic disorders. Our results suggest that quercetin reduces fat accumulation presumably through decreasing oxidative stress and increasing PPARα expression, and the following improvement of gene expression related to steatosis in the liver. C56BL/6J mice were fed for 20 weeks on AIN93G (con) or a Western diet high in fat, cholesterol and sucrose, both with or without 0.05% quercetin for 20 weeks.
Project description:To determine the effect of consumption of a quercetin-rich diet on obesity and dysregulated hepatic gene expression, C56BL/6J mice were fed for 20 weeks on control or a Western diet high in fat, cholesterol and sucrose, both with or without 0.05% quercetin. Chronic dietary intake of quercetin reduced body weight gain and visceral and liver fat accumulation, and improved hyperglyceamia, hyperinsulinaemia, dyslipidaemia in mice fed a Western-style diet. Feeding a Western-style diet altered expression of genes related to inflammatory responses, lipid metabolism and oxidative phosphorylation in C57BL/6J mice after 20 weeks. The results from exhaustive gene expression analysis showed that quercetin minimally influenced hepatic gene expression in mice fed the Western diet. The gene screening results (GSEA) were consistent with the notion that it did improve mitochondrial function to some extent. Quantitative RT-PCR analysis indicated that quercetin did influence important regulators of fat accumulation and metabolic disorders. Our results suggest that quercetin reduces fat accumulation presumably through decreasing oxidative stress and increasing PPARα expression, and the following improvement of gene expression related to steatosis in the liver.
Project description:Dietary flavonoids are supposed to be protective against cardiovascular diseases (CVD). Elevated circulating lipid levels and hepatic lipid accumulation are known risk factors for CVD. We investigated the effects and underlying molecular mechanisms of the flavonoid quercetin on hepatic lipid metabolism in mice with diet induced body weight gain and hepatic lipid accumulation. Adult male mice received a high-fat diet without or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Body weight gain was 29% lower in quercetin-fed mice (p<0.01), while the energy intake was not significantly different. Quercetin supplementation reduced hepatic lipid accumulation with 71% (p<0.05). 1H nuclear magnetic resonance serum lipid profiling revealed that the supplementation lowered serum lipids (p<0.0001). Global gene expression profiling of liver showed that key target genes of the transcription factor Constitutive androstane receptor (Car; official symbol Nr1i3) were regulated, in particular Cytochrome P450 2b (Cyp2b) genes. Quercetin can decrease high-fat diet induced body weight gain, hepatic lipid accumulation and serum lipid levels, which might be explained by the regulation of Cytochrome P450 genes under transcriptional control of CAR, an effect which is likely dependent on dietary background. Liver samples were obtained from 24 C57BL/6J male adult mice. All mice started with a three week adaptation phase, in which they were fed a normal-fat diet. During the intervention of 12 weeks, the mice received a high-fat diet without (HF) or with supplementation of 0.33% (w/w) quercetin (HF-Q). Based on visual inspection, three arrays lacked homogenous hybridization and were therefore excluded.
Project description:Elevated circulating lipid levels are known risk factors for cardiovascular diseases (CVD). In order to examine the effects of quercetin on hepatic lipid metabolism and detailed serum lipid profiles, mice received a mild-high-fat diet without (control) or with supplementation of 0.33% (w/w) quercetin for 12 weeks. Gas chromatography and 1H nuclear magnetic resonance were used to measure quantitatively serum lipid profiles and whole genome microarray analysis was used to identify the responsible mechanisms in liver. There were no significant differences found in mean body weight, energy intake and hepatic lipid accumulation between the quercetin and control group. In serum of quercetin-fed mice, TG levels were decreased with 15%, poly unsaturated fatty acids (PUFA) were increased with 14% and saturated fatty acids were decreased. Palmitic acid, oleic acid, and linoleic acid were all decreased in quercetin-fed mice by 9-15%. Both palmitic acid and oleic acid can be oxidized by omega-oxidation. Indeed, gene expression profiling showed that quercetin increased hepatic lipid metabolism, especially omega-oxidation. At the gene level, this was reflected by the up regulation of cytochrome P450 (Cyp) 4a10, Cyp4a14, Cyp4a31 and Acyl-CoA thioesterase 3 (Acot3). Two relevant regulators, Cytochrome P450 oxidoreductase (Por, rate limiting for cytochrome P450s) and the transcription factor Constitutive androstane receptor (Car; official symbol Nr1i3) were also up regulated in the quercetin-fed mice. We conclude that quercetin intake increased hepatic lipid omega-oxidation and lowered corresponding circulating lipid levels, a process that may involve Por and Car, and results in a potential beneficial CVD preventive effect. Liver samples were obtained from 36 C57BL/6J male adult mice. All mice started with a three week adaptation phase, in which they were fed a mild-high-fat diet. 12 mice were sacrificed immediately after the adaptation phase (t=0). The other 24 mice received the mild-high-fat diet without (HF) or with supplementation of 0.33% (w/w) quercetin (HF-Q) for 12 weeks.
Project description:We showed that diets containing 0.1% or 0.5% quercetin lowered the STZ-induced increase in blood glucose levels and improved plasma insulin levels. A cluster analysis of the hepatic gene expressions showed that 0.5% quercetin diet suppressed STZ-induced alteration of gene expression. Gene set enrichment analysis (GSEA) and quantitative RT-PCR analysis showed that the quercetin diets had their greatest suppressive effect on the STZ-induced elevation of expression of cyclin dependent kinase inhibitor p21(WAF1/Cip1) (Cdkn1a). In this experiment, we determined the effect of quercetin on healthy control BALB/c mice that were fed the AIN93G diet containing 0, 0.1, 0.5 or 1% quercetin for 2 weeks. GSEA and one-way ANOVA did not detect any significant changes in hepatic gene expression in normal mice as a result of a quercetin diet. Using a linear modeling approach and the empirical Bayes statistics, we found that Ubc were significantly reduced by both the 0.5% and 1% quercetin. Six-week-old male mice were divided into 4 groups of 6 mice each, housed in groups of 3 per cage, and fed a standard purified AIN-93G diet containing 0% (Control), 0.1% (0.1), 0.5% (0.5), or 1% quercertin (1.0) for 2 weeks.
Project description:Quercetin is a food component that may ameliorate the diabetic symptoms. We examined hepatic gene expression of BALB/c mice with streptozotocin (STZ)-induced diabetes to elucidate the mechanism of the protective effect of dietary quercetin on diabetes-associated liver injury. We fed STZ-induced diabetic mice with diets containing 0.1% or 0.5% quercetin for 2 weeks and compared the patterns of hepatic gene expression in these groups of mice using a DNA microarray. Diets containing 0.1% or 0.5% quercetin lowered the STZ-induced increase in blood glucose levels and improved plasma insulin levels. A cluster analysis of the hepatic gene expressions showed that 0.5% quercetin diet suppressed STZ-induced alteration of gene expression. Gene set enrichment analysis (GSEA) and quantitative RT-PCR analysis showed that the quercetin diets had their greatest suppressive effect on the STZ-induced elevation of expression of cyclin dependent kinase inhibitor p21(WAF1/Cip1) (Cdkn1a). Six-week-old male mice were divided into 4 groups of 6 mice each, housed in groups of 3 per cage. After 1 week mice were intraperitoneally injected with STZ. Mice (n=6) in the untreated control group did not receive any treatment. After 1 week, 18 mice showing non-fasting blood glucose levels of 230-400 mg/dL were divided into 3 groups: one group was fed with AIN93G only (control group), the others with an AIN93G diet containing 0.1% or 0.5% quercetin (Funakoshi, Tokyo, Japan) for 2 weeks.
Project description:We showed that diets containing 0.1% or 0.5% quercetin lowered the STZ-induced increase in blood glucose levels and improved plasma insulin levels. A cluster analysis of the hepatic gene expressions showed that 0.5% quercetin diet suppressed STZ-induced alteration of gene expression. Gene set enrichment analysis (GSEA) and quantitative RT-PCR analysis showed that the quercetin diets had their greatest suppressive effect on the STZ-induced elevation of expression of cyclin dependent kinase inhibitor p21(WAF1/Cip1) (Cdkn1a). In this experiment, we determined the effect of quercetin on healthy control BALB/c mice that were fed the AIN93G diet containing 0, 0.1, 0.5 or 1% quercetin for 2 weeks. GSEA and one-way ANOVA did not detect any significant changes in hepatic gene expression in normal mice as a result of a quercetin diet. Using a linear modeling approach and the empirical Bayes statistics, we found that Ubc were significantly reduced by both the 0.5% and 1% quercetin.
Project description:Both the 0.05% and 1% querceitn diets did not significantly affect the body weight, fat accumulation, and blood components. However, 0.05% quercetin significantly increased the glutathione/oxidized glutathione ratio in the liver. Moreover, the 1% quercetin diet reduced the lipid peroxidation markers 8-isoprostane in plasma and malondialdehyde in the liver, epididymal adipose tissues, and small intestine. Although comprehensive gene expression analysis dot not detect the genes with significantly different expression levels among the groups of mice, RT-PCR analysis showed that the 1% quercetin diet significantly induced the expression of the antioxidant enzymes Gpx1, Cat, and Sod1 in the liver and Gpx1 and Cat in the epididymal adipose tissues. The transcription factor nuclear factor E2-related factor 2 (Nrf2) was slightly induced in the nuclear fraction of the livers of mice fed the 1% quercetin diet. Quercetin may induce antioxidant enzymes by directly or indirectly activating the Nrf2 pathway in the liver. Five-week-old male mice were fed a AIN-93G diet containing 0% (Control), 0.05% (0.05% quercetin diet), or 1% quercertin (1% quercetin diet) for 20 weeks.