Evaluation of renal function in the juvenile obesity induced by fat diet after weaning in rats: role of the renin angiotensin system

• Grant number: 12/11698-6
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: July 01, 2012
• End date: April 30, 2016
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Mirian Aparecida Boim
• Grantee: Rosemara Silva Ribeiro
• Host Institution: Escola Paulista de Medicina (EPM). Universidade Federal de São Paulo (UNIFESP). Campus São Paulo. São Paulo , SP, Brazil
• Associated research grant: 10/51904-9 - Renin angiotensin and kallikrein kinin systems in hypertension, obesity, diabetes, desnutrition and sepsis: molecular, cellular and physiopathologic mechanisms, AP.TEM

Abstract

Obesity is defined as a disorder of the systems regulating body weight and is often associated with Metabolic Syndrome (MS), defined as a set of diseases that severely affect the organism. Both obesity and MS are responsible for the development of many diseases such as dyslipidemia, hypertension, inflammation, nephropathy and others. Among the mechanisms involved in the development of these pathologies the Renin Angiotensin System (RAS) is of relevance, since obesity is associated with hyper stimulation of the RAS. It is well established that physical exercise has many beneficial effects including renoprotection. Thus, this study will to evaluate the relationship between obesity induced early after weaning on the renal function and then effects of RAS suppression and the physical exercise. Three weeks old male Wistar rats will be fed with a high fat diet during 8 weeks. Then animals will be divided into the following groups: control (CT); control + exercise (CTEX), high fat diet (FD); high fat diet + exercise (FDEX); high fat diet+losartan (FDLos) and standard diet (SD), which will receive a standard diet instead fat diet. The exercise will consist of treadmill running and will last eight weeks. It will be analyzed the hemodynamic parameters, renal function, lipid profile and glycemia. Body weight, food intake and water and tail blood pressure (plethysmography) will be tested weekly. The animals will be placed in metabolic cage at the beginning, middle and end of the protocol for collection of urine for determination of proteinuria, creatinine and electrolytes. At the end of the protocol blood sample will be collected for analysis of lipid profile, glucose, creatinine and electrolytes. The kidneys, liver and adipose tissue are removed for histological and immunohistochemical detection of inflammatory markers and components of the RAS. Preliminary results showed that after 8 weeks of fat diet, there was no difference in body weight gain and systolic blood pressure between groups CT and FD, but the animals of the FD group showed macroscopic increase in abdominal fat content. In addition, they presented decreased urinary volume and lower water intake. (AU)