Fructose-enriched diet modifies antioxidant status and lipid metabolism in spontaneously hypertensive rats

OBJECTIVE: High-fructose consumption in industrial countries has been shown to induce metabolic abnormalities or syndrome X. Changes in antioxidant defense are unknown in hypertension associated with metabolic disorders induced by high-fructose feeding. METHODS: Twenty spontaneously hypertensive rats were assigned to one of two groups; one received a fructose-enriched diet (60% fructose) and the other a starch diet. After a 13-wk diet period, total antioxidant status was assessed in the blood and liver by monitoring the rate of free radical-induced red blood cell hemolysis. Antioxidants (enzymes and vitamins) were determined in blood and liver. Gene expression of antioxidant enzymes (copper/zinc superoxide dismutase and glutathione peroxidase) were also investigated in hepatic tissue. RESULTS: Fructose-fed rats showed blood pressure values similar to that of control rats but had increased glycemia and insulinemia. The antioxidant capacity in the blood of the fructose-fed group represented by copper/zinc superoxide dismutase and glutathione peroxidase activities and ascorbic acid was lower. However, the fructose diet enhanced the total antioxidant capacity of liver correlated with increased antioxidant enzyme activities and retinol concentrations. Gutathione peroxidase mRNA expression was decreased in livers of spontaneously hypertensive rats fed the fructose diet. CONCLUSION: Fructose feeding negatively affects antioxidant capacity in the blood of hypertensive rats but improves this capacity in the liver.