The effects of wild blueberry consumption on plasma markers and gene expression related to glucose metabolism in the obese Zucker rat.
Impaired fasting blood glucose is one of the landmark signs of metabolic syndrome, together with hyperinsulinemia, dyslipidemia, hypertension, and a chronic proinflammatory, pro-oxidative, and prothrombotic environment. This study investigates the effect of wild blueberry (WB) consumption on blood glucose levels and other parameters involved in glucose metabolism in the obese Zucker rat (OZR), an experimental model of metabolic syndrome. Sixteen OZRs and 16 lean littermate controls (lean Zucker rat [LZR]) were fed an 8% enriched WB diet or a control (C) diet for 8 weeks. Plasma concentrations of glucose, insulin, glycated hemoglobin GHbA1c, resistin, and retinol-binding protein 4 (RBP4) were measured. Expression of the resistin, RBP4, and glucose transporter GLUT4 genes was also determined both in the liver and the abdominal adipose tissue (AAT). Plasma glycated hemoglobin HbA1c, RBP4, and resistin concentrations were significantly lower in OZRs following the WB diet (-20%, -22%, and -27%, respectively, compared to C diet, P<.05). Following WB consumption, resistin expression was significantly downregulated in the liver of both OZRs and LZRs (-28% and -61%, respectively, P<.05), while RBP4 expression was significantly downregulated in the AAT of both OZRs and LZRs (-87% and -43%, respectively, P<.05). All other markers were not significantly affected following WB consumption. In conclusion, WB consumption normalizes some markers related to glucose metabolism in the OZR model of metabolic syndrome, but has no effect on fasting blood glucose or insulin concentrations.
1Department of Food Science and Human Nutrition, University of Maine, Orono, Maine.
Stefano
S
Vendrame
2Division of Human Nutrition, Department of Food, Environmental and Nutritional Sciences, Università degli Studi di Milano, Milan, Italy.
Alice
A
Zhao
1Department of Food Science and Human Nutrition, University of Maine, Orono, Maine.
Thomas
T
Merrow
1Department of Food Science and Human Nutrition, University of Maine, Orono, Maine.
Dorothy
D
Klimis-Zacas
D050153:Abdominal Fat / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D029798:Blueberry Plants; D004032:Diet; D015536:Down-Regulation; D005638:Fruit; D015870:Gene Expression; D051275:Glucose Transporter Type 4 / Q000378:metabolism; D006442:Glycated Hemoglobin / Q000378:metabolism*; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D008099:Liver / Q000378:metabolism; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism; D011924:Rats, Zucker; D052243:Resistin / Q000097:blood*; D054839:Retinol-Binding Proteins, Plasma / Q000378:metabolism*
D015415:Biomarkers; D001786:Blood Glucose; D051275:Glucose Transporter Type 4; D006442:Glycated Hemoglobin; D007328:Insulin; D052243:Resistin; D054839:Retinol-Binding Proteins, Plasma; C532035:Rbp4 protein, rat; C495694:Slc2a4 protein, rat
GLUT4; RBP4; anthocyanins; insulin; metabolic syndrome; resistin