Impact of repeated bouts of eccentric exercise on myogenic gene expression |
| |
Authors: | Andreas Costa Hicham Dalloul Hargita Hegyesi Peter Apor Zsolt Csende Levente Racz Mark Vaczi Jozsef Tihanyi |
| |
Institution: | (1) Department of Biomechanics, Faculty of Physical Education and Sport Sciences, Semmelweis University, Budapest, Hungary;(2) Department of Genetics, Cell and Immunobiology, Semmelweis University, Budapest, Hungary |
| |
Abstract: | Evidence indicates that repeated-bouts of eccentric exercise (EE) do not exacerbate the extent of muscle damage indices, as
compared to a single-bout. We hypothesized that molecular adaptations, under repeated-bouts of EE, would include suppression
of muscle repair inhibitory factors such as myostatin and up-regulation of muscle repair positive regulatory factors such
as myogenic regulatory factors (MRFs). Fifteen males were recruited for this study. The exercise group (n = 9) successfully completed six sets of 15 reps of maximum voluntary eccentric contractions, for six consecutive days, using
a dynamometer (Multicont-II). Blood and muscle biopsy samples were obtained from each subject 1 week prior to exercise, 2 days
post the first training session, and 24 h after the last training session. Gene expression levels were determined using real-time
RT-PCR. Blood samples were analyzed for creatine kinase (CK) and lactate-dehydrogenase (LDH) activity. Repeated-bouts of EE
induced a large down-regulation of myostatin mRNA (−73%) which persisted throughout the study. The responses of MRFs were
mild. At day 3 only myogenin increased significantly (1.9 fold) while MyoD decreased by 45%. Surprisingly, at day 7, despite
the presence of muscle damage indices, all MRFs returned to the pre-exercise levels. The results of the present study showed
that repeated-bouts of EE, for six consecutive days, dramatically decreased Myostatin mRNA expression but impaired the expression
patterns of MRFs such that, with the exception of myogenin that showed a moderate non-sustained increase, MyoD and MYf5 response
was minimal.
Grants: Funding was provided by the Ministry of Health of the Hungarian Government. Grant number: ETT 388/2003. |
| |
Keywords: | Muscle damage Myostatin Myogenic regulatory factors Ki-67 p21 |
本文献已被 PubMed SpringerLink 等数据库收录! |
|