title: The effects of omega-3 fatty acid supplementation on dexamethasone-induced muscle atrophy.
abstract: 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 of Wistar rats 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, and Atrogin-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 of Myogenin, and increased the expression of Atrogin-1. Conclusion. Food supplements containing n-3 are usually healthful, but they may potentiate some of the side effects of glucocorticoids.
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Alan
authors: 0000-0003-4015-9262
authors: A
authors: Fappi
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Tiago S
authors: TS
authors: Godoy
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Jessica R
authors: JR
authors: Maximino
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Vanessa R
authors: VR
authors: Rizzato
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Juliana de C
authors: Jde C
authors: Neves
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Gerson
authors: 0000-0002-9667-0716
authors: G
authors: Chadi
authors: Department of Neurology, University of São Paulo, No. 455, Dr. Arnaldo Avenue, 01246-903 São Paulo, SP, Brazil.
authors: Edmar
authors: 0000-0002-4991-6760
authors: E
authors: Zanoteli
mesh_terms: D000818:Animals; D002849:Chromatography, Gas; D003907:Dexamethasone; D019587:Dietary Supplements; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology* / Q000627:therapeutic use*; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000473:pathology; D009124:Muscle Proteins / Q000378:metabolism; D009133:Muscular Atrophy / Q000139:chemically induced* / Q000188:drug therapy* / Q000473:pathology; D009929:Organ Size / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017208:Rats, Wistar; D044843:SKP Cullin F-Box Protein Ligases / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015431:Weight Loss / Q000187:drug effects
chemical_list: D015525:Fatty Acids, Omega-3; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; C474033:FoxO3 protein, mouse; D009124:Muscle Proteins; D014157:Transcription Factors; D003907:Dexamethasone; C486691:Fbxo32 protein, mouse; D044843:SKP Cullin F-Box Protein Ligases; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3