Effects of omega-3 rich fish oil supplementation on lymphocytes of the Goto-Kakizaki rats

• Grant number: 22/01256-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2022
• End date: December 31, 2023
• Field of knowledge: Biological Sciences - Physiology - General Physiology
• Principal Investigator: Renata Gorjao
• Grantee: Elvirah Samantha de Sousa Santos
• Host Institution: Pró-Reitoria de Pós-Graduação e Pesquisa. Universidade Cruzeiro do Sul (UNICSUL). São Paulo , SP, Brazil
• Associated research grant: 18/09868-7 - Cellular and molecular mechanisms of insulin resistance and inflammation in obese Wistar rats and lean Goto-Kakizaki rats: causes and associations with diet and physical exercise, AP.TEM

Abstract

Type II diabetes mellitus (T2DM2) is the most prevalent form of diabetes and is related to genetic and environmental factors. The development of obesity has been one of the main causes associated with insulin resistance (IR) and T2DM. However, there is a high number of non-obese patients who present this pathology. The Goto-Kakizaki (GK) rats are an experimental model that develop a well-defined picture of IR and DM2, without being obese. Thus, the aim of this study is to investigate the effects of n-3 fatty acid supplementation on the polarization process of T lymphocytes. Goto-Kakizaki (GK) rats (n=16) will be selected and compared to Wistar rats (n=16). Supplementation with n-3 fatty acids will be performed in 8 weeks of age animals and will be continued for 8 weeks. In the groups supplemented with n-3 fatty acids, fish oil containing 540 mg of EPA and 100 mg of DHA (HiOMEGA, Naturalis, São Paulo) will be used, at a dose of 2 g per kg of body mass, three times a week, administered by gavage. The respective non-supplemented groups will receive the same volume of water. The glucose tolerance test (GTT) and the insulin tolerance test (ITT) will be performed in the seventh week of the experimental protocol. On the day of euthanasia, the animals will be weighed, and the naso-anal length will be evaluated. After euthanasia, the following adipose tissues will be removed and weighed: epididymal, retroperitoneal and subcutaneous. Lymphocytes will be isolated from the spleen and the following parameters will be evaluated: immunophenotyping of Th1, Th2, Th17 and T regulatory lymphocytes by flow cytometry; analysis of the expression of genes involved in lymphocyte polarization (IL-10, IL-4, TNF-±, INF-gamma, IL-17, Gata-3, T-bet, FoxP3, Ror-gamma) by real-time PCR and phosphorylation of proteins involved in lymphocyte activation such as Akt, ERK1/2, IkB and STAT3 by Western-blotting. Our hypothesis is that supplementation with n-3 fatty acids should decrease the polarization for the Th1 and Th17 profile, increasing the profile of Treg cells and modulating the expression of genes involved with this polarization. In this way, we will be able to evaluate the application of n-3 fatty acid supplementation in the treatment of immunological alterations promoted by DM2 in the absence of obesity.(AU)