01-11-2007 | Original Article
The influence of eccentric exercise on mRNA expression of skeletal muscle regulators
Published in: European Journal of Applied Physiology | Issue 4/2007
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To evaluate change in myostatin, follistatin, MyoD and SGT mRNA gene expression using eccentric exercise to study mechanisms of skeletal muscle hypertrophy. Young (28 ± 5 years) and older (68 ± 6 years) men participated in a bout of maximal single-leg eccentric knee extension on an isokinetic dynamometer at 60°/s: six sets, 12–16 maximal eccentric repetitions. Muscle biopsies of the vastus lateralis were obtained from the dominant leg before exercise and 24 h after exercise. Paired t tests were used to compare change (pre versus post-exercise) for normalized gene expression in all variables. Independent t tests were performed to test group differences (young vs. older). A probability level of P ≤ 0.05 was used to determine statistical significance with Bonferroni adjustments. We observed no significant change in myostatin (−0.59 ± 2.1 arbitrary units (AU); P = 0.42), follistatin (0.22 ± 3.4; P = 0.85), MyoD (0.23 ± 3.1; P = 0.82), or SGT (1.2 ± 6.4; P = 0.58) mRNA expression in young subjects 24 h after eccentric exercise. Similarly, we did not observe significant change in myostatin (−3.83 ± 8.8; P = 0.23), follistatin (−2.66 ± 5.2; P = 0.17), MyoD (−0.13 ± 3.1; P = 0.90), or SGT (−1.6 ± 3.5; P = 0.19) mRNA expression in older subjects. Furthermore, the non-significant changes in mRNA expression were not different between young and older subjects, P > 0.23 for all variables. Our data suggests that a single bout of maximal eccentric exercise does not alter myostatin, follistatin, MyoD or SGT mRNA gene expression in young or older subjects.