Many conditions are associated with muscle atrophy including inactivity, aging, sepsis, diabetes, cancer and steroid therapy. All these conditions produce muscle atrophy due to increase of protein degradation and/or reduction of protein synthesis involving at least five systems: lisosomal, calpains, caspases, metalloproteinase, and ubiquitin-proteosome. The steroids produce atrophy acting in almost all theses systems. Considering that the steroids have been used commonly in the medical practice, the identification of drugs or nutritional supplements that are able to alleviate the side effects of the steroids under the skeletal muscle would be very important for the medical practice. The Fatty Acid Ômega-3 has been showing be effective in attenuating muscle atrophy in cachexia Cancer, among others benefits to human body systems. The objective of this study is to assess the effect of the Omega-3 fatty acid supplementation on the prevention of the muscle atrophy induced by the steroid Dexamethasone. Treated and non treated rats with Omega-3 will be subjected to the dexamethasone administration. The cross sectional area of the muscle fiber types, the expression of the proteins related to the Akt/mTOR pathway, and the muscular transcriptional factors MyoD and myogenin will be assessed using histological, immunohistochemical and Western blot methods. The expression of atrogenes (atrogin-1 e MuRF1) and transcription factors MyoD and myogenin will be analyzed by Real-Time PCR. The identification of the nutritional supplements that are able to alleviate the side effects of steroids on skeletal muscle, i.e. muscle atrophy, and the potential molecular pathways involved in this process, will be very important for the medical practice.
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