Effects of high-intensity interval training and detraining on telomerase activity, p53 protein levels and oxidative status in rat skeletal muscle
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Authors
1Department of Exercise Physiology, Faculty of Exercise Physiology, University of Birjand
2Cellular and Molecular Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences
3Department of Animal Sciences, Faculty of Agriculture, University of Birjand
Abstract
Introduction: Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes. Excessive telomere shortening leads to cellular senescence. Exercise training through the various mechanisms cause of maintain telomere length. High-intensity interval training (HIIT) due to the numerous benefits it has attracted much attention. The physiological adaptations induced by this form of training, are very variable and determined by a myriad of factors including the precise nature of the exercise stimulus (i.e. the intensity, duration and number of intervals performed). The purpose of this study was to investigate the effects of two types of high-intensity interval training with short and long-term interval and detraining on telomerase enzyme activity, p53 protein, total antioxidant capacity (TAC) and total oxidative status (TOS) levels in rat gastrocnemius muscle.
Methodology: For this purpose, 54 male Wistar rats (aged 12 weeks) were randomly assigned into three equal groups (n=18), including HIIT with short-term interval (HIITSh: 16×1 min work at of 80-95% VO2max, interspersed by periods of 1 min active rest at 50-60% VO2max), HIIT with long-term interval (HIITL: 4×4 min work at of 80-95% VO2max, interspersed by periods of 4 min active rest at 50-60% VO2max) and control (CT). Rats were sacrificed after 48 hours of the last training session and at the end of the 4 week detraining period and the gastrocnemius muscle was isolated to measure the telomerase enzyme activity, p53 protein, TAC and TOS levels. Data were analysed by use of one-way ANOVA and the Tukey test for post hoc analyses (P<0.05).
Results: No change were found in telomerase enzyme activity, p53 protein, TAC and TOS levels after training period in both HIIT groups in compared to control group (P>0.05). After detraining period p53 levels significantly increased in detrained HIITSh compared to control group (P=0.004) and TOS levels significantly increased in detrained HIITSh compared to trained HIITSh and HIITL groups (P=0.001 and 0.002, respectively).
Discussion: It seems that exercise training interventions in the short-period (2 months) do not increase telomerase activity in skeletal muscle and short-period exercise training through other pathways such as reducing oxidative stress helps maintain telomere length, but detraining leads to a partial or complete loss of training-induced adaptationsØ› that this rate declines is faster in training with a short-term interval.
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