title: Effects of high EPA and high DHA fish oils on changes in signaling associated with protein metabolism induced by hindlimb suspension in rats.
abstract: The effects of either eicosapentaenoic (EPA)- or docosahexaenoic (DHA)-rich fish oils on hindlimb suspension (HS)-induced muscle disuse atrophy were compared. Daily oral supplementations (0.3 mL/100 g b.w.) with mineral oil (MO) or high EPA or high DHA fish oils were performed in adult rats. After 2 weeks, the animals were subjected to HS for further 2 weeks. The treatments were maintained alongside HS At the end of 4 weeks, we evaluated: body weight gain, muscle mass and fat depots, composition of fatty acids, cross-sectional areas (CSA) of the soleus muscle and soleus muscle fibers, activities of cathepsin L and 26S proteasome, and content of carbonylated proteins in the soleus muscle. Signaling pathway activities associated with protein synthesis (Akt, p70S6K, S6, 4EBP1, and GSK3-beta) and protein degradation (atrogin-1/MAFbx, and MuRF1) were evaluated. HS decreased muscle mass, CSA of soleus muscle and soleus muscle fibers, and altered signaling associated with protein synthesis (decreased) and protein degradation (increased). The treatment with either fish oil decreased the ratio of omega-6/omega-3 fatty acids and changed protein synthesis-associated signaling. EPA-rich fish oil attenuated the changes induced by HS on 26S proteasome activity, CSA of soleus muscle fibers, and levels of p-Akt, total p70S6K, p-p70S6K/total p70S6K, p-4EBP1, p-GSK3-beta, p-ERK2, and total ERK 1/2 proteins. DHA-rich fish oil attenuated the changes induced by HS on p-4EBP1 and total ERK1 levels. The effects of EPA-rich fish oil on protein synthesis signaling were more pronounced. Both EPA- and DHA-rich fish oils did not impact skeletal muscle mass loss induced by non-inflammatory HS.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil gmarzuca@gmail.com.
authors.forename: Gabriel Nasri
authors.initials: GN
authors.lastname: Marzuca-Nassr
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil Massey Institute of Food Science and Technology, College of Health Massey University, Albany, New Zealand.
authors.forename: Kaio Fernando
authors.initials: KF
authors.lastname: Vitzel
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Luís Gustavo
authors.initials: LG
authors.lastname: De Sousa
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Gilson M
authors.initials: GM
authors.lastname: Murata
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Amanda Rabello
authors.initials: AR
authors.lastname: Crisma
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Carlos Flores
authors.initials: CF
authors.lastname: Rodrigues Junior
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Phablo
authors.initials: P
authors.lastname: Abreu
authors.affiliation: Department of Lipids Laboratory, Food Science & Nutrition, Faculty of Pharmaceutical Science University of São Paulo, São Paulo, Brazil.
authors.forename: Rosângela Pavan
authors.initials: RP
authors.lastname: Torres
authors.affiliation: Department of Lipids Laboratory, Food Science & Nutrition, Faculty of Pharmaceutical Science University of São Paulo, São Paulo, Brazil.
authors.forename: Jorge
authors.initials: J
authors.lastname: Mancini-Filho
authors.affiliation: Institute of Physical Activity Sciences and Sport, Cruzeiro do Sul University, São Paulo, Brazil.
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Hirabara
authors.affiliation: School of Biomedical Sciences, CHIRI Biosciences Curtin University, Perth, Australia.
authors.forename: Philip
authors.initials: P
authors.lastname: Newsholme
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences University of São Paulo, São Paulo, Brazil.
authors.forename: Rui
authors.initials: R
authors.lastname: Curi
mesh_terms: D000818:Animals; D004281:Docosahexaenoic Acids / Q000008:administration & dosage* / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D005395:Fish Oils / Q000737:chemistry*; D053263:Gene Regulatory Networks / Q000187:drug effects; D019417:Hindlimb Suspension / Q000009:adverse effects*; D008297:Male; D018482:Muscle, Skeletal / Q000187:drug effects; D020966:Muscular Disorders, Atrophic / Q000209:etiology / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D005395:Fish Oils; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
keywords: Hindlimb suspension; muscle atrophy; omega‐3 fatty acids; protein synthesis/degradation