Alterações estruturais cardíaca e aórtica na menopausa cirúrgica associada à hipertensão renovascular em ratos

• Autor(a) principal: Mendonça, Leonardo de Souza
• Data de Publicação: 2007
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/7866
• topic: Menopause; Renovascular hypertension; Rats; Cardiac remodeling; Aorta; Menopausa; Hipertensão renovascular; Remodelação ventricular; Aorta; Ratos; Menopausa; Hipertensão Renovascular; Ratos; Remodelamento cardíaco; Aorta; CNPQ::CIENCIAS BIOLOGICAS::MORFOLOGIA

Menopause and hypertension independently may alter cardiovascular remodeling, but little is known about their association on left ventricular and aortic wall remodeling. Rats were separated into four groups of six animals each: Sham group, OVX group (ovariectomized rats), 2K1C (two kidneys one clip rats), and OVX+2K1C group, and leaved for 11 weeks. Left ventricle (LV) and thoracic aorta were removed and analyzed (light microscopy, immunohistochemistry and stereology). Vaginal cytology showed Sham and 2K1C rats cycling normally, whereas OVX and OVX+2K1C rats were persistently in diestrus or proestrus. Blood pressure compared to the Sham group increased 12% in the OVX group, 35% higher in both the 2K1C and OVX+2K1C groups. The LV mass/tibia length ratio and the cross-sectional area of cardiomyocytes increased in all groups except the Sham group. The intramyocardial vascularization was reduced around 30% in relation to the Sham group, with no difference among OVX, 2K1C and OVX+2K1C groups. The cardiac interstitium increased more than 45% in groups 2K1C and OVX+2K1C comparing to the Sham group, but no significant difference was seen between the Sham and the OVX groups. The number of LV cardiomyocyte nuclei was gradually smaller in the OVX group followed by the 2K1C group and the OVX+2K1C group, with no difference between the 2K1C and the OVX+2K1C groups. Positive immunostaining for angiotensin II AT1 receptor was observed in smooth muscle cell layer of the aortic tunica media in all groups. Present findings demonstrated that ovariectomy and renovascular hypertension act independently enhancing BP in rats, the stimulus to elevated BP being stronger, as well as the consequences to the adverse cardiac remodeling, in renovascular hypertension than in surgically-induced menopause.