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.
Original language | English |
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Pages (from-to) | 137-145 |
Number of pages | 9 |
Journal | Journal of Nutrition |
Volume | 144 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2014 |
Keywords
- MUSCLE-LENGTHENING CONTRACTIONS
- MYOGENIC GENE-EXPRESSION
- HUMAN SKELETAL-MUSCLE
- SATELLITE CELL
- MESSENGER-RNA
- OLDER MEN
- SUPPLEMENTATION AUGMENTS
- MYOFIBER HYPERTROPHY
- ECCENTRIC EXERCISE
- HUMANS