Aim: Postnatal skeletal muscle growth is strongly associated with a satellite cell pool. Early adolescence might be a crucial period when different exercise training interventions have specific consequence on satellite cells. Pax7 and MyoD have been suggested as the leading indicators of satellite cell activation.Methods: In this study, pre-adolescent male rats (n = 18) were either subjected to an enriched environment that facilitated physical activities or combined training or control for three weeks. The flexor hallucis longus muscle was removed for biochemical and histochemical analysis.Results: Findings demonstrated that exercise trained rats displayed high levels of serum IGF-1 (p <0.05). There was an increase in Pax7 (p <0.05) and MyoD (p <0.001) mRNA expression. A significant increase in the mean fiber area (p <0.01), satellite cell (p <0.001), and myonuclear numbers (p <0.01) were also observed in both intervention groups. Importantly, enriched rats showed lower corticosterone levels (p <0.05) compared to training ones. Regarding performance, trained and enriched rats had significant improvement in forelimb grip strength (p <0.01) and load-carrying capacity (p <0.05).Conclusion: Type of physical exercise is an essential part in changing satellite cells pool. Different and frequent physical activities in an enriched environment can be effective for muscle development.
Background. Neurotrophic factors play an important role in the brain plasticity. The brain developmental processes remarkably occur in the pre-pubertal period, and training interventions during this sensitive period may lead to specific effects. The purpose of this study was to investigate the effects of combined training and activity in an enriched environment on the brain BDNF and VEGF protein levels in the pre-pubertal male rats. Methods. The pre-pubertal male Wistar rats (n=18) were randomly divided into three groups of combined training (CT), enriched environment (EE), and control (C) at postnatal day 22. The combined training included endurance and resistance physical exercises, which performed six days a week. A large cage with various rich stimuli (wheel running, ladder, toys, tunnels) was provided for voluntary physical activity in an enriched environment. The interventions lasted for three weeks, and the brain tissue (right hemisphere) was removed for biochemical evaluations. The BDNF and VEGF protein levels of the brain were measured by the western blotting method. Results. Significant differences found in the BDNF and VEGF levels in this study (P<0.01). The neurotrophic factors were significantly increased in the CT and EE groups. Although VEGF protein level increased in both groups, only enriched rats showed a significant difference. Conclusion. It can be concluded that combined training and voluntary physical activity in an enriched environment in the pre-pubertal period can effective in brain plasticity by increasing the neurotrophic factors.
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