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Immunomodulatory effects of acute stress in toads from Genus Rhinella

Grant number: 15/23801-4
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): June 01, 2016
Effective date (End): July 31, 2019
Field of knowledge:Biological Sciences - Physiology
Principal Investigator:Fernando Ribeiro Gomes
Grantee:Vania Regina de Assis
Home Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:14/16320-7 - Impacts of climate/environmental change on the fauna: an integrative approach, AP.PFPMCG.TEM
Associated scholarship(s):17/04802-5 - Long-term corticosterone treatment effects on stress and immune response in cane toads (Rhinella marina), BE.EP.PD

Abstract

Glucocorticoids modulate immune response in complex ways with both immuno-enhancing and immunosuppressive effects in vertebrates exposed to different stressors. Such bimodal effects have been associated with variation in duration and intensity of the stress response. Given that natural populations have been exposed to a multitude of stressors, a better understanding of the functional association between duration and intensity of the stress response, the resulting changes in glucocorticoid plasma levels and their impact on different aspects of immune response emerges as a keystone for vertebrate conservation strategies. We will investigate the interrelationships between corticosterone plasma levels (hereinafter referred to as CORT), and the innate immune response. Therefore, we will use the transdermal corticosterone application, to simulate the changes related to the increase in CORT in an acute stress event, in order to understand the immunomodulatory effects on different parameters of cellular and humoral immune response. Additionally, after a challenge with lipopolysaccharide (LPS), we will quantify the production of proteins related to the inflammatory immune response. Our study model will be male toads from genus Rhinella. We will test the following predictions: 1) Transdermal application of low concentrations of corticosterone should cause an increase in CORT and immune response; 2) Transdermal application of high concentrations of corticosterone should cause an even higher increase in CORT and decrease immune response; 3) After LPS challenge, animals that received corticosterone should have a decreased production of proteins related to inflammatory immune response than animals that did not receive the hormone; and 4) After LPS challenge animals that received low concentrations of corticosterone should have a higher production of proteins related to inflammatory immune response than animals that received higher concentrations of the hormone. (AU)