IGF-1 receptor evaluation on dexamethasone-induced muscle atrophy associated and non-associated to previous omega-3 fatty acid supplementation

• Grant number: 16/10915-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): August 01, 2016
• Effective date (End): July 31, 2017
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Principal Investigator: Edmar Zanoteli
• Grantee: Pedro Victor Massaroto e Silva
• Host Institution: Faculdade de Medicina (FM). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The mass muscle regulation depends essentially on two regulatory processes dynamic that are opposite: the synthesis and protein degradation. The molecular evaluation pathways responsible for this balance is of great interest to the medical practice as it opens up possibilities for therapeutic and various pathologies including side effects of drugs such as, for example, glucocorticoids (myopathy most common drug). Scientific evidences show interference in various regulatory mechanisms as the transport of amino acids, myogenin, including influence on IGF-1/PI3K/ Akt/mTOR pathway by decreasing the synthesis and increased muscle degradation leading to muscle atrophy. Several therapeutic compounds have been tested in order to prevent muscle atrophy induced by glucocorticoids, however, some without success and others like omega-3, have shown potentiate glucocorticoid-induced muscle atrophy. One of the explanations for this effect is the increase atrogenes (Atrogin-1) reflecting a greater possible blocking the IGF-1 pathway, hypotheses which has not been evaluated. Objective: To evaluate the impact of dexamethasone (DX) on muscle atrophy in supplemented and not supplemented rats with omega-3 (EPA / DHA) and the influence of this combination on the total and phosphorylated IGF-1 receptor expression in skeletal muscle. Methods: The muscle atrophy level will be measure by mATPase technique and expression of the IGF-1 receptor (total and phosphorylated) by western blotting technique.