EFFECTS OF PHYSIOLOGICAL DEPRIVATION OF OVARIAN HORMONES ON CORONARY BED REACTIVITY AND CARDIAC CONTRACTILITY IN SPONTANEOUSLY HYPERTENSIVE RATS - ROLE OF AGING

• Grant number: 23/13420-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: February 01, 2024
• End date: January 31, 2025
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Hugo Celso Dutra de Souza
• Grantee: Giulia Vitória Andrade
• Host Institution: Faculdade de Medicina de Ribeirão Preto (FMRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

Introduction: Systemic arterial hypertension (SAH) is accompanied by a reduction in the cardiac contractile capacity and alterations in the reactivity of the coronary bed. However, in women of reproductive age, this condition may be less severe due to the cardiovascular protection exerted by ovarian hormones. In this context, physiological ovarian failure (menopause) would represent a watershed in this protection, which may result in the development of more severe changes in cardiac contractility and reactivity of the coronary bed. However, it is necessary to separate the effects inherent to the aging process. Objective: To investigate whether physiological ovarian failure in spontaneously hypertensive rats (SHR) results in more severe impairments in cardiac contractility and coronary bed reactivity when compared to normotensive rats (WK), or if aging is a condition that prevails over the impairments in such aspects. Methods: 32 animals (40 weeks old) will be divided into two large groups; group of Wistar Kyoto rats (WK; N=16) and group of spontaneously hypertensive rats (SHR; N=16). Half of each group will undergo ovarian hormone deprivation through ovariectomy (N=8) or SHAM surgery (N=8) at the 60th week of life. All animals will be evaluated using the following protocols: recording of blood pressure and heart rate by plethysmography to be performed on the 40th, 48th, 56th, 64th and 72nd weeks of life and analysis of coronary bed reactivity and ventricular contractility left heart in isolated heart by increasing flow and administration of ²-adrenergic agonists, dobutamine (0.5 - 50 nmol) and salbutamol (1 - 100 nmol).