The antioxidant effects of green tea reduces blood pressure and sympathoexcitation in an experimental model of hypertension

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Garcia, Michelle L. ; Pontes, Roberto B. ; Nishi, Erika E. ; Ibuki, Flavia K. ; Oliveira, Vanessa ; Sawaya, Alexandra C. H. ; Carvalho, Patricia O. ; Nogueira, Fernando N. ; Franco, Maria do Carmo ; Campos, Ruy R. ; Oyama, Lila M. ; Bergamaschi, Cassia T.

• Document type: Journal article
• Source: Journal of Hypertension; v. 35, n. 2, p. 348-354, FEB 2017.
• Web of Science Citations: 15

Abstract

Background: Oxidative stress is a key mediator in the maintenance of sympathoexcitation and hypertension in human and experimental models. Green tea is widely known to be potent antioxidant. Objective: We aimed to evaluate the effects of green tea in a model of hypertension. Methods: Hypertension was induced by the nitric oxide synthase inhibitor {[}N-nitro-L-arginine-methyl-ester (L-NAME); 20mg/kg per day, orally, for 2 weeks] in male Wistar rats. After the first week of L-NAME treatment, animals received green tea ad libitum for 1 week. At the end of the treatment period, blood pressure, heart rate, baroreflex sensitivity, renal sympathetic nerve activity, and vascular and systemic oxidative stress were assessed. Results: L-NAME-treated animals exhibited an increase in blood pressure (165 +/- 2 mmHg) compared with control rats (103 +/- 1mmHg) and green tea treatment reduced hypertension (119 +/- 1 mmHg). Hypertensive animals showed a higher renal sympathetic nerve activity (161 +/- 12 spikes/s) than the control group (97 +/- 2 spikes/s), and green tea also decreased this parameter in the hypertensive treated group (125 5 spikes/s). Arterial baroreceptor function and vascular and systemic oxidative stress were improved in hypertensive rats after green tea treatment. Conclusions: Taken together, short-term green tea treatment improved cardiovascular function in a hypertension model characterized by sympathoexcitation, which may be because of its antioxidant properties. (AU)

• FAPESP's process: 10/09003-4 - Role of renal sympathetic nerve activity in the experimental renovascular hypertension
• Grantee: Erika Emy Nishi
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 13/22522-9 - Role of renal sympathetic nerves on cardiovascular and renal alterations in renovascular hypertension
• Grantee: Ruy Ribeiro de Campos Junior
• Support Opportunities: Regular Research Grants