Electronic Theses and Dissertations

Identifier

6413

Date

2019

Document Type

Thesis

Degree Name

Master of Science

Major

Health and Sport Science

Concentration

Exercise, Sport & Movement Sci

Committee Member

Melissa Puppa

Committee Member

Marie van der Merwe

Committee Member

Keith Martin

Abstract

Background: Omega-3 PUFAs elicit beneficial effects in several muscle atrophy conditions. Objective: Determine if a high-fat diet rich in n-3 is protective of glucocorticoid-induced protein degradation. Methods: Male wild type C57BL/6 mice were randomized into two groups: n-6 (45% fat 177.5 g lard) and n-3 (45% fat 177.5 g Menhaden oil). After 4 weeks on their diets, groups were divided to receive either daily injections of dexamethasone (3 mg/kg/day) or sterile PBS, for 1 week while continuing diets. Results: Dexamethasone reduced gastrocnemius weight by 12% independently of diet. Protein degradation signaling was altered by dexamethasone with increased atrogin-1 expression, decreased phosphorylation of FOXO3a, increased phosphorylation of GSK-3b, and increased myostatin and MURF-1 gene expression. However, the negative effects of dexamethasone were not attenuated by an n-3 high-fat diet. Conclusion: These data support the detrimental effects of dexamethasone on muscle atrophy and report no benefit of an n-3 high-fat diet. Background:Omega-3 PUFAs elicit beneficial effects in several muscle atrophy conditions. Objective: Determine if a high-fat dietrich in n-3 is protective of glucocorticoid-induced protein degradation. Methods: Male wild type C57BL/6 mice wererandomized into two groups: n-6 (45% fat 177.5 g lard) and n-3 (45% fat 177.5 gMenhaden oil). After 4 weeks on their diets, groups were divided to receiveeither daily injections of dexamethasone (3 mg/kg/day) or sterile PBS, for 1week while continuing diets. Results:Dexamethasone reduced gastrocnemius weight by 12% independently of diet.Protein degradation signaling was altered by dexamethasone with increasedatrogin-1 expression, decreased phosphorylation of FOXO3a, increasedphosphorylation of GSK-3b, and increased myostatin and MURF-1 gene expression.However, the negative effects of dexamethasone were not attenuated by an n-3 high-fatdiet. Conclusion: These data supportthe detrimental effects of dexamethasone on muscle atrophy and report nobenefit of an n-3 high-fat diet.

Comments

Data is provided by the student.

Library Comment

Dissertation or thesis originally submitted to the local University of Memphis Electronic Theses & dissertation (ETD) Repository.

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