The Effects of Omega-3 Fatty Acid Supplementation on Dexamethasone-Induced Muscle Atrophy

Corticosteroids cause muscle atrophy by acting on proteasomal and lysosomal systems and by affecting pathways related to muscular trophysm, such as the IGF-1/PI-3k/Akt/mTOR. Omega-3 fatty acid (n-3) has been used beneficially to attenuate muscle atrophy linked to sepsis and cachexia; however, its effect on dexamethasone-induced muscle atrophy has not been evaluated.Objectives. We evaluated whether n-3 supplementation could mitigate the development of dexamethasone-induced muscle atrophy.Methods. Two groups ofWistarrats were orally supplemented with n-3 or vehicle solution for 40 days. In the last 10 days, dexamethasone, or saline solution, was administrated establishing four groups: control, dexamethasone, n-3, and dexamethasone + n-3. The cross-sectional areas of muscle fibers, gene expression (MyoD, Myogenin, MuRF-1, andAtrogin-1), and protein expression (Akt, GSK3β, FOXO3a, and mTOR) were assessed.Results. Dexamethasone induced a significant loss in body and muscle weight, atrophy in type 2B fibers, and decreased expression of P-Akt, P-GSK3β, and P-FOXO3a. N-3 supplementation did not attenuate the negative effects of dexamethasone on skeletal muscle; instead, it caused atrophy in type 1, 2A, reduced the expression ofMyogenin, and increased the expression ofAtrogin-1.Conclusion. Food supplements containing n-3 are usually healthful, but they may potentiate some of the side effects of glucocorticoids.

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Omega-3 Levels and Nicotine Dependence: A Cross-Sectional Study and Clinical Trial

European Addiction Research ◽

10.1159/000439525 ◽

2015 ◽

Vol 22 (3) ◽

pp. 153-162 ◽

Cited By ~ 11

Author(s):

Juçara X. Zaparoli ◽

Eduardo K. Sugawara ◽

Altay A.L. de Souza ◽

Sérgio Tufik ◽

José Carlos F. Galduróz

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Fish Oil ◽

Nicotine Dependence ◽

Cross Sectional Study ◽

Omega 3 Fatty Acids ◽

Omega 3 ◽

Double Blind ◽

Cross Sectional ◽

Omega 3 Fatty Acid

Background: High oxidative stress, which is caused by smoking, can alter omega-3 fatty acid concentrations. Since omega-3 fatty acids play a role in dopaminergic neurotransmission related to dependence, it is important to understand their effects on nicotine dependence. Methods: This research comprised 2 studies. The first one consisted of a cross-sectional evaluation, in which the levels of the most important omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were compared between smokers and non-smokers in a sample of 171 individuals; of them, 120 were smokers and 51 were non-smokers. The other study was a clinical, double-blind, randomized, placebo controlled, in which 63 smokers received daily treatment with capsules of fish oil (a source of omega-3/3 g/day) or mineral oil (used as placebo, also 3 g/day), taken 3 times a day for 90 days. Each fish oil capsules contained approximately 210.99 mg EPA and 129.84 mg of DHA. The outcome was evaluated by means of psychometric and biological measures as well as self-reports of tobacco use. The evaluations were carried out at the beginning of treatment and once a month thereafter (total of 4 times). Outcomes: The omega-3 fatty acid lipid profile showed that smokers present lower concentrations of DHA. After treatment, the omega-3 group showed a significant reduction in their levels of dependence. Interpretation: Smokers showed lower peripheral levels of omega-3, and treatment with the most important omega-3 fatty acids brought about a reduction in nicotine dependence.

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