RESUMO
UNLABELLED: The aim of the present study was to investigate the effect of zinc on the activity of copper-zinc superoxide dismutase (Cu/Zn SOD), the lipid profile, the arterial blood pressure and the morphological changes of the aorta in male spontaneously hypertensive rats (SHR). MATERIALS AND METHODS: The study included 52 male SHR animals. The animals were randomly asigned into three groups to be fed one of three zink diets--in group one animals (G1, control group) the zinc content was 50 mg/kg, in group two (G2)--155 mg/kg and in group three (G3) 250 mg/kg. The laboratory chow zinc content and the zinc and copper serum levels were measured by a direct flame atomic-absorption spectrophotometry. The Cu/Zn SOD activity was measured in the erythrocytes using a reagent from RANSOD (RANDOX Laboratories). Systolic arterial blood pressure was measured on the rat's tail (tail cuff) by an indirect method without anesthesia (Ugo Basile). The lipid profile was determined with ABX reagents (France). Histological investigations of the aortas were performed using histochemical and electron microscopic methods. RESULTS: Statistically significant increase of Cu/Zn SOD activity (p < 0.05) was found in G2 (2276.88 +/- 145.53) and G3 (2337.31 +/- 146.25) in comparison with the control group of animals (2099.46 +/- 111.73). There was significant decrease of serum LDL levels (p < 0.05) in G3 (1.09 +/- 0.32) compared with G2 (1.19 +/- 0.42) and G1 (1.62 +/- 0.28). Increased number of migrated smooth muscle cells was found in G1 animals. Lipid drops were increased in the aortic wall of SHR animals and then decreased after zinc diet was applied. CONCLUSIONS: The results indicate that high zinc content in the diet has a protective effect as it increases Cu/Zn SOD activity, decreases the LDL serum levels and the lipid infiltration of the aorta in male SHR animals.
