A single oral dose of fructose induces some features of metabolic syndrome in rats: role of oxidative stress

Abstract

Background and aims: To determine if a single oral dose of fructose to rats reproduces some features of metabolic syndrome observed after chronic administration and if so, to investigate its mechanisms.

Methods and results: Systolic blood pressure was measured in rats before and after oral administration of fructose, and in animals pretreated with lipoic acid, methyldopa, losartan or streptozotocin. In other rats, glucose, insulin, uric acid, and insulin sensitivity index, were determined before and after fructose or lipoic acid plus fructose. Glutathione was measured in liver before and after fructose administration. In aortic rings from other rats, incubation with mannitol, fructose, or fructose plus lipoic acid was evaluated on the relaxation by acetylcholine. Fructose produced a moderate increase in blood pressure, which was prevented by lipoic acid or streptozotocin. Methyldopa and losartan decreased the pressor response minimally. Fructose increased oxidized glutathione, plasma glucose, insulin and uric acid, and diminished the insulin sensitivity index, and the reduced glutathione. Lipoic acid prevented hyperglycemia and hyperuricemia, and improved the insulin sensitivity index. Finally, endothelial dysfunction was prevented by lipoic acid.

Conclusion: A single dose of fructose reproduces some of the features of metabolic syndrome, most changes were caused by oxidative stress and insulin resistance.