Affiliation

• ¹School of Nutrition, Laval University, Institute of Nutraceuticals and Functional Foods, Laval University, Quebec Qc G1V 0A6, Canada
• ²Department of Rehabilitation, Laval University, University Hospital Centre, Laval University, Laurier Blvd, Quebec Qc G1V 4G2, Canada

Corresponding Author

Helene Jacques, School of Nutrition, Paul-Comtois Building, 2425 Agriculture Street, Laval University,Quebec, Canada, Tel: 418-656-2131, ext. 3864; Fax: 418-656-3353; E-mail: helene.jacques@fsaa.ulaval.ca

Citation

Jacques, H., et al. Dietary Cod Protein Improves the IGF1-Akt/PKB Signaling Pathway in Rat Skeletal Muscle during Recovery from Injury. (2015) Int J Food Nutr Sci 2(2): 140-146.

Copy rights

©2015 Jacques, H. This is an Open access article distributed under the terms of Creative Commons Attribution 4.0 International License.

Keywords

Abstract

  The objective of this study was to identify molecular mechanisms underlying the beneficial effects of cod protein feeding on skeletal muscle recovery through detailed analyses of the IGF1-Akt/PKB signaling pathway. Acute mucle injury was induced by injecting bupivacaine in one tibialis anterior of Wistar rats fed isoenergetic diets containing either casein (C), cod protein (CP), or casein supplemented with a mixture of arginine, glycine, taurine and lysine (C⁺), matching their respective levels as in CP; downstream IGF1-Akt/PKB (protein kinase B) effectors were measured post-injury. Rats fed the CP-diet exhibited a  50% reduction of the muscle ring finger1 (MuRF1) level compared with those fed the C-diet (p=0.01), while the reduction induced by the C⁺-diet was intermediary to, but did not differ significantly (p=0.07) from the C-diet at day 2 post-injury. These findings indicate a decrease in the ubiquitination of muscle proteins and their degradation in the CP-group partly because of its high levels of arginine, glycine, taurine and lysine. Futhermore, phospho-Akt Ser⁴⁷³, a phosphorylation required for maximum activation of Akt, was increased in the CP-group at day 5 (p<0.0001) and day 28 post-injury (p=0.002) compared with C, and at day 5 compared with C⁺ (p=0.0005). The phosphorylated form of GSK-3 was also increased with CP feeding at day 28 post-injury compared with C (p=0.05), suggesting enhanced protein synthesis in the CP group. C⁺ enhanced phospho-Akt Ser⁴⁷³ compared with C (p=0.008) only at day 28 post-injury, with no effect on GSK-3 phosphorylation. Therefore, CP may reduce protein degradation induced by muscle injury through early modulation of the ubiquitination process, while enhancing muscle protein synthesis through Akt phosphorylation at later time points.