Efeitos vasculares promovidos pela estrona em ratas Wistar ovariectomizadas
Nenhuma Miniatura disponível
Data
2018-08-31
Autores
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Federal de Goiás
Resumo
Estrone (E1), the major component of Premarin® and predominant estrogen in
postmenopausal women, does not have its vascular effects involving its vasodilatory
mechanism of action completely elucidated. Therefore, the aim of this study was to evaluate
the effects of E1 treatment on the vascular reactivity of isolated aortic rings and blood
pressure in ovariectomized Wistar rats (OVX). For this purpose, 12 week-old Wistar rats were
divided into four experimental groups, Sham (physiological estrous rats treated with vehicle),
OVX (OVX rats treated with vehicle), OVX + E1 (OVX rats treated with 825μg / kg of E1) and
OVX + 17β-estradiol (E2) (OVX rats treated with 15μg / kg of E2). The treatments started
after the 8 weeks of surgery trough subcutaneous pathway for 30 days. At the end of
treatment, blood pressure measurement by tail plethysmograph was performed. In addition,
aortic rings were isolated to evaluate contractile response to phenylephrine (Phe), relaxation
to acetylcholine (ACh) or sodium nitroprusside (NPS) by means of concentration curves. The
response to ACh in rings previously incubated with superoxide dismutase (SOD), catalase
(CAT) or apocynin (NADPH oxidase inhibitor) was also evaluated. The protein expression of
SOD, CAT, NOX 1, NOX 2 and NOX 4 were quantified by Western blotting. Follow-up of the
weight gain after the OVX or Sham procedure was also performed. After euthanasia, the
weight of retroperitoneal fat, uterus and heart were evaluated. E1 treatment decreased body
weight and retroperitoneal fat, increased uterine weight, and corrected both the increased
blood pressure, and the decreased hyperreactivity to Phe vasoconstrictor agent and also
increased endothelium-dependent vasodilatory response to ACh. The effects presented by this
hormone are related to compensatory mechanisms in the activity of antioxidant enzymes such
as SOD and catalase besides the reduction in the expression of the NADPH oxidase NOX 4
isoform. In addition, E1 reverses the increase in total and LDL cholesterol in the OVX group.
Our study confirms the role of oxidative stress in endothelial dysfunction of OVX rats and
further demonstrates that E1 reverses elevation of blood pressure and restores endothelial
function in OVX rats.
Descrição
Palavras-chave
Citação
OLIVEIRA, T. S. Efeitos vasculares promovidos pela estrona em ratas Wistar ovariectomizadas. 2018. 117 f.
Tese (Doutorado em Biologia) - Universidade Federal de Goiás, Goiânia, 2018.