Effects of the association of physical exercise and photobiomodulation in an obese rat experimental model

• Grant number: 19/22970-8
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): October 01, 2020
• Effective date (End): September 30, 2021
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal researcher: Ana Claudia Muniz Renno
• Grantee: Luany Oliveira Costa
• Home Institution: Instituto de Saúde e Sociedade (ISS). Universidade Federal de São Paulo (UNIFESP). Campus Baixada Santista. Santos , SP, Brazil

Abstract

Obesity is a multifactorial disease conditioned by ingesting poor food and physical inactivity thus generating an energy imbalance caused by the bigger accumulation of adipose tissue in relation to energy expenditure, which result in secondary disorders (for example dyslipidemia, and damage resulting by the inflammatory process). Physical exercise is already proven to be the most effective non-pharmacological method for stimulating lipid metabolism and consequent decrease in BMI, obesity control and treatment of diseases associated with overweight. While photobiomodulation works with absorbing electromagnetic irradiation in a specific molecule known as chromophore, which is located on the mitochondrial crest of the cell. Its action therefore becomes effective in modulating and decreasing the inflammatory process and the possibility of converting white adipose tissue to brown. According to previous studies, it is proven that exercise-associated PBM is capable of promoting weight loss and metabolic profile changes, as well as attenuating inflammatory processes, thus helping to control obesity-related risks. Therefore, the objective of the present study is to evaluate the efficacy of enhancing the beneficial effect of exercise using PBM in the treatment of obesity with an experimental model of hyperlipidic diet-induced obesity in rats to resemble the dietary pattern of obese humans. For this, 24 male Wistar rats, three months old and with an average body weight of 300-350 grams will be used at the beginning of the experiment, which will be submitted to the obesity induction model, with water and food at will and divided into three groups of eight obese rats in each randomly arranged: Control group (G1); Physical exercises (G2); Physical exercise + FBM (G3). Training sessions will begin 4 weeks after the initiation of the obesity induction protocol and will be performed on a treadmill with a speed of 16 m / m, 50 min time, 3 days a week for 8 weeks and FBM treatment will begin 24 concomitant with the initiation of the training protocol. The irradiation will be performed using a low intensity laser unit with the following irradiation parameters: semiconductor Gallium Aluminum Arsenide Diode (GaAlAs), 808 nm wavelength, 30 mW optical output power. The laser application will be held 3 times a week and / or after physical training. There will be a total of 14 sessions within 8 weeks. The above parameters had been chosen in view of the results of previous studies. Metabolic profile data will be analyzed through glycemic curve test and insulin resistance test, mitochondrial activity through Western blotting, evaluation of inflammatory infiltrate through histopathological analysis, adipocyte area through histomorphometry and the presence of anti-inflammatory factors through immunohistochemistry.