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Effects of exercise training in metabolic, hemodynamic and autonomic parameters in experimental model of menopause submitted to high-fat diet

Grant number: 19/06973-7
Support type:Scholarships in Brazil - Scientific Initiation
Effective date (Start): September 01, 2019
Effective date (End): July 31, 2020
Field of knowledge:Health Sciences - Physical Education
Principal Investigator:Iris Callado Sanches
Grantee:Marino Siket de Souza Pereira
Home Institution: Faculdade de Ciências Biológicas e da Saúde. Universidade São Judas Tadeu (USJT). São Paulo , SP, Brazil

Abstract

After menopause, decreased ovarian function alters lipid metabolism, resulting in increased visceral fat mass. Many population studies have shown that excess adipose tissue, especially in the abdomen, is closely related to the risk of cardiovascular complications. In fact, the incidence of cardiovascular disease increases significantly after menopause. Evidence suggests connections of increased blood pressure with reduced levels of estrogen. In addition, there is much evidence that the autonomic nervous system plays a key role in the pathophysiology of metabolic complications, both in humans and in animal models. In this sense, exercise training has been shown to be potentially beneficial for the management of metabolic and cardiovascular complications after menopause. The general objective of the present study will be to investigate the effect of exercise training on metabolic, hemodynamic and autonomic parameters in an experimental model of menopause submitted to a high-fat diet. For this, 32 C57BL/6J mice (approximately 10 weeks-aged) divided into 4 groups (n=8 in each) were used: sedentary submitted to control diet (CSN), sedentary ovariectomized submitted to control diet (OSN), sedentary ovariectomized submitted to high-fat diet (OSD), and trained ovariectomized submitted to high-fat diet (OTD). The high-fat diet will have 60% of the caloric content provided by lipids, and will be offered from the 10th week of life of the animals. After 4 weeks of diet, the oral glucose tolerance test (OGTT) will be performed, which will be repeated at the end of the protocol. After the first OGTT, ovariectomy (bilateral ovarian withdrawal) will be performed to induce ovarian deprivation. One week after surgery, aerobic exercise training will begin, lasting 4 weeks (5d/week, 40min-1h/day, mild to moderate intensity, 50-70% of maximum running capacity). At the end of the training period, the animals will be cannulated for direct recording of arterial pressure (CODAS, 4kHz). Arterial pressure record will be evaluated using the spectral analysis tool (FFT) for analysis of cardiovascular autonomic modulation. At the end of the protocol, the white adipose tissue and the soleus and gastrocnemius muscles will be collected and weighed. The data will be analyzed with the Student t test or ANOVA one way, and values of p <0.05 will be considered significant.