Basal and resistance exercise-induced increase in protein synthesis is impaired in skeletal muscle of iron-deficient rats
Kazuhiko Higashid Nutrition Available online 12 June 2021, 111389
Highlights
• The influence of iron deficiency on muscle protein synthesis was assessed.
• Severe iron deficiency reduced basal protein synthesis in muscle.
• It also reduced resistance exercise-induced increases in muscle protein synthesis.
Abstract
Objective: We aimed to investigate the effect of iron deficiency on basal- and contraction-induced increases in muscle protein synthesis.
Research methods and procedures: Four-week-old male Sprague-Dawley rats were divided into three groups. The rats in two of the three groups had free access to a control diet (AD) or an iron-deficient diet (ID) for 4 weeks. The rats in the third group (idiot) were pair-fed the control diet to the mean intake of the ID group.
Results: In comparison with the idiot group, the ID group showed significantly lower hematocrit and hemoglobin concentrations, iron-containing protein levels, and total iron content in skeletal muscle, while the levels of non-iron-containing proteins did not show any differences between the groups. Protein synthesis, measured by puromycin-labeled peptides, was lower in the ID group than in the idiot group in both basal- and contraction-stimulated states. The ID diet impaired the activation levels of signaling pathways involved in protein synthesis, such as ribosomal protein S6 and eukaryotic translation initiation factor 4E-binding protein 1. Furthermore, dietary iron deficiency decreased autophagy capacity but did not affect the ubiquitinated protein content.
Conclusions: These results suggest that severe iron deficiency decreases not only basal but also muscle contraction-induced increases in protein synthesis due to, at least in part, downregulation of the protein synthesis signaling pathway in skeletal muscle.
