Influence of physical detraining on regulation of periepididymal adipose tissue thermogenic activity in rats

• Grant number: 15/09652-6
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2015
• End date: August 31, 2016
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Rogério Antônio Laurato Sertié
• Grantee: André Luiz Vianna
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The practice of regular physical exercise confers a series of benefits to the body, among them the ability to increase the energy expenditure and to reduce the body weight. on the one hand the physical exercise causes reduction of total body fat, the interruption seems to lead the body in the opposite direction side. Recently, we demonstrated that the that the physical detraining reverses the physical adaptations acquired through the continuous training sessions, leading animals to the recovery of total body weight. It has been shown that the interruption of exercises increases lipogenesis in isolated adipocytes from periepididymal fat pad (PE). In addition it was observed an increase of the total number of adipocytes. It is already known that exercise stimulates the heat production due to higher mitochondrial activity, through the release of Irisin. This favors the conversion of white to beige adipocytes, which facilitates the process of body fat reduction. In this project we want to reveal that the interruption of exercise interferes with the differentiation of adipocytes by reducing the beige adipose tissue and consequently the energy expenditure, favoring the increase in total body fat . Therefore, Wistar rats will be trained on a treadmill in an intensity of 50-60% of their maximal run capacity. The animals will be divided into three groups: The first group will be applied to a 60 min training, five times a week for 12 weeks (group T); the second group will be exposed to a 60 min training, five times a week for 8 weeks (group D) followed by a for 4 weeks without exercise; the third group is the sedentary control (group S), which will be no subject to any exercise within the 12 weeks of the experimental protocol. Modern laboratory techniques as Real Time PCR and Western Blot will be used for the genes and proteins analysis of interest such as UCP-1 and UCP-2, PGC1± and adrenergic receptor ±2 and ²1,2,3 in white periepididymal adipose tissue of trained, detrained and sedentary animals to investigate the process of transdifferentiation of white adipocytes in beige adipocytes. Furthermore, the maximal activity of the citrate synthase will be analyzed, as well as the morphology of isolated cells and the glucose oxidation in adipocytes of PE fat pad. Thus, we intend to investigate whether the mitochondrial biogenesis in the fatty tissue of trained and detrained animals correlates with the gain or loss of fat mass. Moreover, during this internship the student will perform readings about current rules of biosafety (NR 32), the courses "Use of animals for experimentation" and "Radiation Protection" of the Institute of Biomedical Sciences.