RESUMO
BACKGROUND: Oxidative stress is closely related to cardiovascular diseases, such as atherosclerosis. Increasing dietary antioxidants, such as alpha-tocopherol, may prevent these diseases. However, in some pathologies, such as hypertension, oxidative stress is enhanced, thus alpha-tocopherol requirements may be raised. MATERIAL/METHODS: In eleven-week-old spontaneously hypertensive rats and normotensive Wistar Kyoto rats, we investigated the effects of a four-week very high alpha-tocopherol dietary enrichment (1,200 mg/kg diet, VH) on blood pressure, resistance to free radical aggression, and VLDL+LDL resistance to lipid peroxidation. Platelet aggregation and plasma lipid profile were also investigated. RESULTS: With either diet, hypertensive rats were more protected against oxidative stress than normotensive rats. Their capacity to withstand free radical aggression was better, and their VLDL+LDL particles were less sensitive to lipid peroxidation. In either group, the VH diet did not modify blood pressure values when resistance to free radical aggression was increased, but not the resistance of VLDL+LDL to lipid peroxidation. With the control diet, platelet aggregation was faster and higher in hypertensive rats vs. normotensive rats. It was decreased with the VH diet in hypertensive rats but increased in normotensive rats, when compared to their respective controls. Whatever the diet, plasma triacylglycerol, phospholipid and cholesterol concentrations were lower in hypertensive than in normotensive rats. Only cholesterol concentrations were diminished with the VH diet in hypertensive rats, but not in normotensive rats. CONCLUSIONS: These results indicate that very high alpha-tocopherol dietary amounts decrease cardiovascular risk in hypertensive rats with high oxidative stress, but have less effect on normotensive rats.
