Papel do antioxidante (vitamina C) na modulação da pressão sanguínea em ratos espontaneamente hipertensos (SHR)

• Autor(a) principal: Costa, Milton Vieira
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7784
• topic: Vitamin C; Oxidative stress; Essential hypertension; Spontaneously hypertensive rat; Renin-angiotensin system; Vitamina C; Estresse oxidativo; Hipertensão essencial; Rato espontaneamente hipertenso; Sistema renina-angiotensina; Hipertensão; Vitamina C; Estresse oxidativo; Antioxidantes; Ácido Ascórbico; Ratos Endogâmicos SHR; CNPQ::CIENCIAS BIOLOGICAS::MORFOLOGIA

The essential hypertension, as well as the Spontaneously Hypertensive Rat (SHR), is characterized by the development of high BP (BP) with advancing age, with no identified primary cause. It is well established that this animal model presents OxS concomitant hypertension. The mechanism, by which the antioxidant reduces the pressure, is not clear, for this reason, it is necessary to evaluate the behavior of enzymes involved in the homeostasis of BP. Male Wistar-Kyoto (WKY) rats and SHR received ascorbic acid, 200 mg / kg / day by orogastric gavage with lasted five weeks. The BP, Left Ventricular Hypertrophy (LVH), renin-angiotensin system (RAS), Atrial Natriuretic Peptide (ANP) and OxS results have been extensively compared among groups by plethysmography, stereology, confocal laser scanning microscopy, transmission electron microscopy, western blotting and RT-qPCR analysis. The SHR treated with ascorbic acid reduced BP and LVH. Also, the enzymes involved in the homeostasis of BP, renin and Angiotensin Converting Enzyme (ACE) normalized, as well as Angiotensin II type 1 receptor (AT1R). The large amount of ANP granules in SHR group was reduced by treatment with ascorbic acid. Oxidative balance was reestablished in SHR treated with this antioxidant. OxS in SHR elevates renin levels and BP. These reactive oxygen species may be involved in the signaling mechanism for increased expression in ANP atrial myocytes. These data also show that treatment with antioxidant (vitamin C) reduces OxS and normalizes BP at least partly by reducing rates of renin.