title: Acute dietary protein intake restriction is associated with changes in myostatin expression after a single bout of resistance exercise in healthy young men.
abstract: Skeletal muscle satellite cells (SCs) play an important role in the myogenic adaptive response to exercise. It remains to be established whether nutrition plays a role in SC activation in response to exercise. In the present study, we assessed whether dietary protein alters the SC response to a single bout of resistance exercise. Twenty healthy young (aged 21 ± 2 y) males were randomly assigned to consume a 4-d controlled diet that provided either 1.2 g protein ⋅ kg body weight(-1) ⋅ d(-1) [normal protein diet (NPD)] or 0.1 g protein ⋅ kg body weight(-1) ⋅ d(-1) [low protein diet (LPD)]. On the second day of the controlled diet, participants performed a single bout of resistance exercise. Muscle biopsies from the vastus lateralis were collected before and after 12, 24, 48, and 72 h of post-exercise recovery. SC content and activation status were determined using immunohistochemistry. Protein and mRNA expression were determined using Western blotting and reverse transcription polymerase chain reaction. The number of myostatin + SCs decreased significantly at 12, 24, and 48 h (range, -14 to -49%; P < 0.05) after exercise cessation, with no differences between groups. Although the number of myostatin + SCs returned to baseline in the type II fibers on the NPD after 72 h of recovery, the number remained low on the LPD. At the 48 and 72 h time points, myostatin protein expression was elevated (86 ± 26% and 88 ± 29%, respectively) on the NPD (P < 0.05), whereas it was reduced at 72 h (-36 ± 12% compared with baseline) in the LPD group (P < 0.05). This study demonstrates that dietary protein intake does not modulate the post-exercise increase in SC content but modifies myostatin expression in skeletal muscle tissue. This trial was registered at clinicaltrials.gov as NCT01220037.
authors.affiliation: NUTRIM School for Nutrition, Toxicology, and Metabolism, Maastricht University, Maastricht, The Netherlands.
authors.forename: Tim
authors.initials: T
authors.lastname: Snijders
authors.forename: Lex B
authors.initials: LB
authors.lastname: Verdijk
authors.forename: Bryon R
authors.initials: BR
authors.lastname: McKay
authors.forename: Joey S J
authors.initials: JS
authors.lastname: Smeets
authors.forename: Janneau
authors.initials: J
authors.lastname: van Kranenburg
authors.forename: Bart B B
authors.initials: BB
authors.lastname: Groen
authors.forename: Gianni
authors.initials: G
authors.lastname: Parise
authors.forename: Paul
authors.initials: P
authors.lastname: Greenhaff
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D000222:Adaptation, Physiological; D000328:Adult; D004044:Dietary Proteins / Q000008:administration & dosage / Q000494:pharmacology*; D002149:Energy Intake; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D055435:Myostatin / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D012016:Reference Values; D055070:Resistance Training; D012146:Rest / Q000502:physiology; D032496:Satellite Cells, Skeletal Muscle / Q000187:drug effects* / Q000378:metabolism; D055815:Young Adult
chemical_list: D004044:Dietary Proteins; D055435:Myostatin; D012333:RNA, Messenger