Cardiovascular changes to water deprivation in rats fed a high-fat diet: possible mechanisms

• Grant number: 23/04381-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Débora Simões de Almeida Colombari
• Grantee: Helena Oliveira Deróbio
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

Overweight and obesity are major risk factors for many chronic diseases, including cardiovascular diseases such as hypertension. There is a high prevalence of obesity and hypertension in postmenopausal women. Women also ingest more sodium than men, correlating with higher blood pressure (BP) values. In this study, using an animal model, we will verify if obese female rats with free access to 0.3 M NaCl solution, have a higher BP level than non-obese female rats, and if with ovariectomy (surgical menopause) obese female rats will have an even higher levels of BP. The role of estrogen will be studied in this situation with hormone replacement. In addition to the study in a situation of euhydration (EU), we will also verify cardiovascular alterations in a situation of water deprivation (WD), a natural occurrence in humans and animals. The peripheral mechanisms involved with cardiovascular changes, whether in a situation of EU or WD will be studied. Holtzman female rats will be used with initial weight between 280-300 g fed a standard diet (SD; 11% of calories from fat) or a high-fat diet (HFD; 46% of calories from fat). Part of the SD and HFD female rats will be ovariectomized (OVX) and after 6 weeks, part of the SD-OVX and HFD-OVX rats will be treated for 7 days with estradiol and in the following 4 days, still under treatment, cardiovascular experiments will be carried out in an EU or WD rats. Our hypothesis is that HFD-OVX rats will have higher BP values than the other groups and that WD potentiates this response, whether due to hyperactivity of the renin-angiotensin or sympathetic system.