european college of sport science

Thursday, June 25th, 2009
content. However, it is not clear which factor is important to increase satellite cell content. Therefore, this study investigated the effects of
difference in intensity and duration of endurance training on satellite cell content in rat plantaris muscle.
Methods: Forty-one 17-week-old female Sprague Dawely rats were assigned to one of four groups: control (CON: n=8), high intensity and
high duration (H90: n=7), high intensity and low duration (H30: n=8), low intensity and high duration (L90: n=9) and low intensity and low
duration (L30: n=9) group. Exercise intensities were controlled by running speed and grade (High: 25-30m / min · 0-18%, Low: 25-30m /
min · 0-3%). Exercise durations were 90 and 30min for high and low duration, respectively. Training groups exercised 5 days / week on a
motor driven treadmill for 10 weeks. After the training period, the plantaris muscle was removed under anesthesia, weighted and frozen
with liquid nitrogen. Serial transverse sections (7µm thick) were made using a microtome at -20ºC. Satellite cells were immunohistochemically
stained, visualized and identified by using anti-Pax7 and anti-laminin antibody and DAPI. The number of muscle fibers, mean
fiber area, myonuclei and satellite cells were measured. To determine mean fiber area for each fiber types, mATPase staining was performed.
Results: Endurance training increased percentage of satellite cells (CON: 1.42 ± 0.35%, L30: 1.56 ± 0.30%, L90: 1.73 ± 0.34%, H30: 2.21 ±
0.31%, H90: 2.49 ± 0.29%), however, there were no significant differences in muscle weight, mean muscle fiber area and myonuclei per
muscle fiber between groups. The percentage of satellite cells was no significant difference between H30 and H90, but there was significantly
higher in both H30 and H90 groups compared with L30, L90 and CON group (P < 0.05).
Conclusion
It was concluded that intensity of the endurance training affect an increase in number of satellite cells in the rat plantaris muscle.
EXERCISE TRAINING IMPROVES AGING-INDUCED DECREASE OF PPAR-ALPHA AND PGC-1ALPHA PROTEIN LEVELS IN
CARDIAC AND SKELETAL MUSCLES
IEMITSU, M., MAEDA, S.
INTERNATIONAL PACIFIC UNIVERSITY
Background and Purpose: Exercise training improves aging-induced decrease of oxidative metabolic capacity in mitochondria of cardiac
and skeletal muscle1. However, the mechanisms underlying improving oxidative metabolic capacity in the cardiac and skeletal muscles
by exercise training are unclear. Peroxisome proliferator-activated receptor (PPAR)-alpha regulates 3-hydroxyacyl CoA dehydrogenase
(HSD) gene expression via PPRE transcriptional activation. Peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-
1alpha) regulates cytochrome oxidase (COX) gene expression via transcriptional activation of nuclear respiratory factor-1 (NRF-1). We
investigated whether aging-induced alteration in PPAR-alpha and PGC-1alpha protein levels and these signals in cardiac and skeletal
muscle is improved by exercise training.
Methods: We used cardiac and epitrochlearis muscles of sedentary young rat (4-month old), sedentary aged rat (23-month old), and
swim-trained aged rat (23-month old, swimming training for 8-week, 5days/wk, 90min/day). PPAR-alpha and PGC-1alpha protein expressions
were detected by immunoblot analysis. For determination of HSD, NRF-1 and COX mRNA, reverse transcription-polymerase
chain reaction (RT-PCR) was used. Furthermore, enzyme activities of HSD and COX were measured.
Result: The activity of HSD and COX, which are key enzymes of energy metabolic capacity, in cardiac and epitrochlearis muscles were
significantly lower in the sedentary aged rats compared with the sedentary young rats, and were higher in the trained-aged rats than the
sedentary-aged rats. PPAR-alpha and PGC-1alpha protein levels in cardiac and epitrochlearis muscles were significantly lower in the
sedentary aged rats than the sedentary young rats, and were higher in the trained-aged rats than the sedentary-aged rats. Additionally,
in the heart, activity of PPRE DNA binding to the transcriptional regulating region and mRNA expression of HSD altered in association with
changes of the PPAR-alpha protein levels. Moreover, the mRNA expression of NRF-1, activity of NRF DNA binding to the transcriptional
regulating region and mRNA expression of COX altered in association with changes of the PGC-1alpha protein levels.
Conclusion: These findings suggest that exercise training may improve aging-induced impairment of metabolic enzyme activity associated
with PPAR-alpha and PGC-1alpha proteins in cardiac and skeletal muscles.
Grant: Supported by grants from the Ministry of Education, Culture, Sports, Science and Technology of Japan (20700563) and the Sasagawa
Scientific Research Grant from The Japan Science Society.
Reference:
1. Iemitsu M, et al. Exercise training improves aging-induced downregulation of VEGF angiogenic signaling cascade in hearts. Am J
Physiol Heart Circ Physiol 2006;291:H1290-H1298.
SIRTUIN ACTIVATOR INCREASES ENDURANCE FOR RATS ARTIFICIALLY SELECTED TO HIGH RUNNING CAPACITY
HART, N., SARGA, L., KOLTAI, E., BRITTON, S., KOCH, L., LAMBERT, P., RADAK, Z.
SEMMELWEIS UNIVERSITY
Sirtuins are NAD+ dependent protein deacetylases and suggested regulators of aging, fat and sugar metabolisms, DNA repair, mitochondrial
biogenesis and fiber type differentiation of skeletal muscle. SIRT activators like caloric restriction or supplementation of resveratrol
have been shown to increase mean life span via alteration of central cellular processes. In the present study we trained selectively
bred 24 generations for intrinsic aerobic high running capacity (HCR) or low running capacity (LCR) rats and some groups were supplemented
by SIRT activator for 4 month. Twelve weeks exercise training significantly increased the VO2max in both groups, and the increase
was almost twice as large in the LCR (26%) rats than at HCR (15%). The supplementation of SIRT stimulator (SRT501) significantly
enhanced the VO2max and the running distant at HCR rats, while no significant effects were observed at LCR rats. SIRT stimulator also
improved the performance at gripping. The biochemical analysis of gastrocnemius muscle revealed that both exercise training and SIRT
stimulator effected the activity of SIRT1 at the nuclear extracts, moreover it appears that the NAD biosythetic activity also altered by exercise
training. Our data suggest that SIRT stimulator selectively effected HCR rats and resulted in significant improvement of aerobic endurance
capacity.
LYMPHOCYTE NUCLEAR DNA DAMAGE IN HUMANS: AGE AND AEROBIC CAPACITY RELATION
SOARES, J., MOTA, M.P., GAIVÃO, I.
UNIVERSIDADE DE TRÁS-OS-MONTES E ALTO DOURO
LYMPHOCYTE NUCLEAR DNA DAMAGE IN HUMANS: AGE AND AEROBIC CAPACITY RELATION
OSLO/NORWAY, JUNE 24-27, 2009 191