Efeitos cardiovasculares e antioxidantes do tratamento crônico com extrato hidroalcoólico de romã (punica granatum) em ratas hipertensas
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Data
2014-12-18
Autores
Lima, Nathalie Tristão Banhos Delgado de
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Universidade Federal do Espírito Santo
Resumo
Punica granatum or pomegranate (PG), a phytoestrogen, possesses several biological actions and may be beneficial for the prevention of disease, including cardiovascular disease. We hypothesised that treatment with pomegranate would improve cardiovascular parameters. The purpose of this study was to examine the cardiovascular and antioxidant effects of treatment with pomegranate in hypertensive and ovariectomized rats. Four weeks after their births, SHR females were divided into two groups, Sham and OVX, and were then subdivided into groups treated with pomegranate extract (250 mg/ kg) or filtered water (Vehicle) for 30 days by gavage. The systolic blood pressure (SBP) was measured by tail plethysmography at the beginning and end of treatment, when the animals were 8 weeks of age. The animals were killed by decapitation; the heart was removed and perfused according to the Langendorff method. The blood and tissues were collected for biochemical analysis. The protein expression of SOD-2, catalase, and eNOS were analysed in coronary arteries by western blot. The baseline coronary perfusion pressure (CPP) was determined. A dose-response curve to bradykinin (BK) was performed followed by inhibition with L-NAME. After 30 days, we observed a significant increase in systolic blood pressure only in the OVX group, and treatment promoted a significant reduction in SBP in both groups. The baseline CPP was reduced in the Sham group. The bradykinin-induced relaxation was significantly higher in the treated group. Ovariectomy significantly reduced the relaxation, which was restored by treatment with pomegranate, and L-NAME abolished the BK-induced relaxation in all groups, showing this result is a NO-dependent effect. There was an increase in SOD expression in the OVX-PG group and no change in the catalase level. However, the ovariectomy significantly reduced eNOS and gp91phox levels when compared to the Sham group. The MDA levels were significantly reduced in the Sham-PG group, indicating decreased oxidative stress. We observed a reduction in total cholesterol and LDL in the Sham-PG group compared to the Vehicle group. There was a reduction in triglyceride levels in the OVX-PG group. In addition to these effects, we observed an increase in oestrogen levels only in the OVX group and progesterone in Sham and OVX groups. Therefore, we suggest a therapeutic role of pomegranate extract on the cardiovascular system because it was shown to lower blood pressure, improve relaxation and a lipid profile that may be linked to a reduction in oxidative stress. We also observed that treatment promoted an increase in body weight of the OVX group and did not change the relative weight of the uterus in both groups. Furthermore, the treatment increased the weight of all fat cushions in both groups, except mesenteric which was increased only in the OVX group. Therefore, we suggest a therapeutic role of pomegranate extract on the cardiovascular system, since it has been shown that lowering blood pressure, improvement in relaxation and lipid profile may be associated to a reduction in oxidative stress
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Pomegranate extract , Antioxidant enzymes , Phytoestrogen , Vasorelaxation , Reactive oxygen species , Hypertension , Extrato de romã , Enzimas antioxidantes , Fitoestrógenos , Vaso relaxamento , Espécies reativas de oxigênio , Hipertensão