Effects of Exercise Training on Mitochondrial Fatty Acid β-Oxidation in the Kidneys of Dahl Salt-Sensitive Rats

Exercise training (Ex) has anti-hypertensive and renal protective effects. In this study, we investigate the effects of Ex on mitochondrial fatty acid metabolism in the kidneys of Dahl salt-sensitive (Dahl-S) rats fed a high-salt (HS) diet. Eight-week-old, male Dahl-S rats were divided into three groups: (1) normal-salt diet, sedentary (NS-Sed), (2) HS diet, sedentary (HS-Sed), and (3) HS-Ex. The NS and HS groups were fed a diet containing 0.6% and 8% NaCl, respectively. The HS-Ex group performed treadmill running for 8 weeks (5 days/week; 60 min/day at 16-20 m/min, 0% gradient). Renal function and the expression of enzymes and regulators of β-oxidation and electron transport chain (ETC) complexes were assessed. HS increased systolic blood pressure and proteinuria, and Ex ameliorated these defects. HS also reduced creatinine clearance, and Ex ameliorated it. HS reduced the renal expression of enzymes of β-oxidation (carnitine palmitoyltransferase type I (CPTI) and acyl-CoA dehydrogenases (CADs)) and the related transcription factors peroxisome proliferator-activated receptor α (PPARα) and PPARγ-coactivator-1α (PGC-1α), and Ex restored this. HS also reduced the renal expression of enzymes in ETC complexes, and Ex restored this expression. Ex ameliorates HS-induced renal damage by upregulating enzymes involved in fatty acid β-oxidation and ETC complexes via increases in PPAR-α and PGC-1α expressions in the kidneys of Dahl-S rats. These results suggest that Ex may have beneficial effects on HS-induced mitochondrial dysfunction in the kidney.

Multi-omics analysis explores the effect of chronic exercise on liver metabolic reprogramming in mice

Background: The effect of exercise on human metabolism is obvious. However, the effect of chronic exercise on liver metabolism in mice is less well described. Methods: The healthy adult mice running for 6 weeks as exercise model and sedentary mice as control were used to perform transcriptomic, proteomic, acetyl-proteomics, and metabolomics analysis. In addition, correlation analysis between transcriptome and proteome, and proteome and metabolome was conducted as well. Results: In total, 88 mRNAs and 25 proteins were differentially regulated by chronic exercise. In particular, two proteins (Cyp4a10 and Cyp4a14) showed consistent trends (upregulated) at transcription and protein levels. KEGG enrichment analysis indicated that Cyp4a10 and Cyp4a14 are mainly involved in fatty acid degradation, retinol metabolism, arachidonic acid metabolism and PPAR signaling pathway. For acetyl-proteomics analysis, 185 differentially acetylated proteins and 207 differentially acetylated sites were identified. Then, 693 metabolites in positive mode and 537 metabolites in negative mode were identified, which were involved in metabolic pathways such as fatty acid metabolism, citrate cycle and glycolysis/gluconeogenesis. Conclusion: Based on the results of transcriptomic, proteomics, acetyl-proteomics and metabolomics analysis, chronic moderate intensity exercise has certain effects on liver metabolism and protein synthesis in mice. Chronic moderate intensity exercise may participate in liver energy metabolism by influencing the expression of Cyp4a14, Cyp4a10, arachidonic acid and acetyl coenzyme A and regulating fatty acid degradation, arachidonic acid metabolism, fatty acyl metabolism and subsequent acetylation.

The Effects of Exercise Training on Glucose Homeostasis and Muscle Metabolism in Type 1 Diabetic Female Mice

Although exercise training is an important recommendation for the management of type 1 diabetes (T1D), most of the available research studies predominantly focus on male subjects. Given the importance of sex as a biological variable, additional studies are required to improve the knowledge gap regarding sex differences in T1D research. Therefore, the purpose of this study was to examine the role of exercise training in mediating changes in glucose homeostasis and skeletal muscle metabolism in T1D female mice. Female mice were injected with streptozotocin (STZ) to induce T1D. Two weeks after STZ injection, control (CON) and STZ mice were exercise trained on a treadmill for 4 weeks. Aerobic exercise training failed to improve glucose tolerance, prevent the decrease in body weight and adipose tissue mass, or attenuate muscle atrophy in T1D female mice. However, insulin sensitivity was improved in T1D female mice after exercise training. Aerobic exercise training maintained skeletal muscle triglyceride content but did not prevent depletion of skeletal muscle or liver glycogen in T1D mice. Gene expression analysis suggested that T1D resulted in decreased glucose transport, decreased ketone body oxidation, and increased fatty acid metabolism in the skeletal muscle, which was not altered by exercise training. These data demonstrate that 4 weeks of aerobic exercise training of a moderate intensity is insufficient to counteract the negative effects of T1D in female mice, but does lead to an improvement in insulin sensitivity.

Chronic Exercise as a Modulator of Cognitive Control: Investigating the Electrophysiological Indices of Performance Monitoring

Exercise may influence components of executive functioning, specifically cognitive control and action monitoring. We aimed to determine whether high level exercise improves the efficacy of cognitive control in response to differing levels of conflict. Fitter individuals were expected to demonstrate enhanced action monitoring and optimal levels of cognitive control in response to changing task demands. Participants were divided into the highly active (HA) or low-active group based on self-reported activity using the International Physical Activity Questionnaire. A modified flanker task was then performed, in which the level of conflict was modulated by distance of distractors from the target (close, far) and congruency of arrows (incongruent, congruent). Electroencephalography (EEG) was collected during 800 trials; trials were 80% congruent, 20% incongruent, 50% close, and 50% far. The error-related negativity (ERN) and error positivity (Pe) were extracted from the difference wave of correct and incorrect response locked epochs, the N2 from the difference wave of congruent and incongruent stimulus locked epochs and the P3 from stimulus locked epochs. The HA group showed a larger Pe amplitude compared to the low-active group. Close trials elicited a larger N2 amplitude than far trials in the HA group, but not the low-active group, the HA group also made fewer errors on far trials than on close trials. Finally, the P3 was smaller in the lowest conflict condition in the HA, but not the low-active group. These findings suggest that habitual, high levels of exercise may influence the endogenous processing involved in pre-response conflict detection and the post-error response.

Effects of chronic exercise on the inhibitory control of children and adolescents: A systematic review and meta-analysis

Inhibitory control is a main component of executive functions that relate to the ability to control prepotent responses and to resist interferences. Deficits in inhibitory control have been associated with numerous disorders, but exercise has become a promising approach to benefit this domain. This systematic review and meta-analysis aims to provide synthesized information and effect size calculations of the benefits of chronic exercise interventions on the inhibitory control of healthy children and adolescents. A systematic search of PubMed, PsycINFO, MEDLINE, ERIC, SPORTDiscus, and PsycArticles identified 4166 articles to be screened for eligibility. A total of 10 studies (3138 participants) met the inclusion criteria. A random-effects analysis model was performed in three variables: accuracy, reaction time and combined scores. The results showed a very small but statistically significant effect in accuracy (d = 0.14, 95% CI 0.01 to 0.27, P =.04), and two almost null effects (statistically non-significant), in the reaction time (d = 0.03, 95% CI -0.10 to 0.16, P =.62) and the combined scores (d = 0.06, 95% CI -0.03 to 0.15, P =.17). Despite the high number of studies that reported positive outcomes, this meta-analysis found only modest benefits in the inhibitory control of healthy children and adolescents after they participated in different chronic exercise interventions. The strict inclusion criteria of this study and the high variability in the designs of the exercise interventions included, among other reasons, might explain the obtained results.

Effects of Acute and Chronic Exercises on Executive Function in Children and Adolescents: A Systemic Review and Meta-Analysis

Background: Physical exercises can affect executive function both acutely and chronically, with different mechanisms for each moment. Currently, only a few reviews have elaborated on the premise that different types of exercises have different mechanisms for improving executive function. Therefore, the primary purpose of our systematic review was to analyze the effects of acute and chronic exercises on executive function in children and adolescents. Objective: We identified acute and chronic exercise studies and randomized controlled trials (RCTs) of executive function in children and adolescents that reported overall effect, heterogeneity, and publication bias of acute and chronic exercises on executive function. Methods: We searched for RCTs of exercise interventions in children and adolescents from databases including PubMed, Web of Science, Scopus, The Cochrane Library, CNKI (China National Knowledge Infrastructure), and Wanfang, from January 1 2009 to December 31 2019. We performed methodological quality evaluations on the included literature using the Physiotherapy Evidence Database Scale (PEDro) and graded evidence with a meta-analysis using Stata 12.0 software. Results: In total, 36 RCTs were included (14 acute exercises, 22 chronic exercises); the overall results of the meta-analysis (4,577 students) indicated that acute exercises significantly improved working memory (standardized mean difference (SMD) = -0.72; 95% confidence interval (CI) -0.89 to -0.56; p < 0.001), inhibitory control (SMD = -0.25; 95% CI -0.40 to -0.09; p = 0.002), and cognitive flexibility (SMD = -0.34; 95% CI -0.55 to -0.14; p < 0.005), whereas chronic exercises significantly improved working memory (SMD = -0.54; 95% CI -0.74 to -0.33; p < 0.001), inhibitory control (SMD = -0.30; 95% CI -0.38 to -0.22; p < 0.001), and cognitive flexibility (SMD = -0.34, 95 % CI -0.48 to -0.20, p < 0.001). Conclusion: Acute and chronic exercises can effectively improve the executive function of children and adolescents. The effects on inhibitory control and cognitive flexibility are considered as small effect sizes, while the effects on working memory are considered as moderate effect size. Limited by the quantity and quality of the included studies, the above conclusions need to be verified with more high-quality studies.

Exercise and intestinal permeability: another form of exercise-induced hormesis?

Regular aerobic exercise has numerous benefits on human physiology, arguably by serving as a hormetic stressor resulting in positive adaptations over time. It has long been known that aerobic exercise at a variety of intensities and durations induces intestinal permeability, which is a feature of many pathologies of the gastrointestinal tract and metabolic diseases. Given the health benefits of exercise, it seems unlikely that intestinal permeability induced by exercise outweighs the positive adaptations. In fact, a growing body of evidence suggests adoption of exercise regimens lasting weeks to months improves indicators of intestinal permeability. In this brief review, we summarize factors contributing to acute exercise-induced intestinal permeability and what is known about chronic exercise and the gut barrier. Additionally, we outline known and theoretical adaptations of the gut to chronic exercise that may explain emerging reports that exercise improves markers of gut integrity.

Rhythmic Physical Activity Intervention: Exploring Feasibility and Effectiveness in Improving Motor and Executive Function Skills in Children

Introduction

Increasing literature has emerged investigating the importance of considering the qualitative characteristics of physical activity (PA) interventions and sports as well as considering the role of motor competence in the exercise-cognition interplay. The purpose of this pilot study was to examine the feasibility and effectiveness of a rhythmic PA intervention compared to a standard physical education program, on motor and hot and cool executive function (EF) skills.

Methods

Children ages 6-11 were enrolled in one of the two programs: a rhythmic program (n = 22) and a physical education program (n = 17), both meeting for 30 min, twice per week, for 7 weeks. The rhythmic program emphasized moving to the beat of music and moving in various rhythmic patterns with whole body movements, clapping, and drumsticks. The children also created their own rhythmic patterns and socially engaged with other children by working in pairs and sharing their routines with the group. The physical education group engaged in ball skills, locomotor patterns, team sports, and moving through stations in small groups, with no emphasis on rhythm. Pretest and posttest measurements included measurement of balance (Movement ABC-2), cool and hot EF (Flanker, SWAN), and social factors, whereas throughout the implementation period data on affective valence, enjoyment, cognitive engagement, perceived exertion, and PA levels were collected at every lesson in both groups.

Results

The rhythmic program used in this study was feasible, scalable, affordable, and able to be implemented with minimal preparatory time. Children in both groups (rhythmic and physical education) engaged in a similar level of PA and had similar positive experiences from the programs. Both groups improved in balance and cool EF, and there were significant correlations in the change scores between balance and cool EF, as well as between cool EF with hot EF and socio-emotional factors.

Discussion

This study contributes to the literature by exploring the potential value of rhythmic programs as a vehicle in helping children develop motor and EF skills while deriving joy and positive social interactions from the program.

Effects of Moderate- and High-Intensity Chronic Exercise on the Adiponectin Levels in Slow-Twitch and Fast-Twitch Muscles in Rats

Background and objectives: Adipose tissue and skeletal muscle secrete adiponectin, a hormone abundantly secreted by adipocytes, that through the adiponectin receptor, regulate glucose and lipid metabolism. Adiponectin appears to protect skeletal muscles from inflammatory damage induced by oxidative stress. It has been suggested that decreased adiponectin levels could be associated with pathologic conditions, including obesity and diabetes. Furthermore, some studies suggest that exercise could have a beneficial effect by increasing adiponectin levels, but this observation remains controversial. It is also unknown if physical exercise modifies adiponectin expression in skeletal muscles. The aim of this study was to investigate the effect of chronic exercise on serum adiponectin and adiponectin expression in slow-twitch (soleus) and fast-twitch (plantaris) muscles in healthy rats. Materials and methods: Two-month-old male Wistar rats were randomly divided into three groups with n = 6 in each group: control (C), moderate-intensity training (MIT), and high-intensity training (HIT). The rats were conditioned to run on a treadmill for the 8-week period. Forty-eight hours after the last session, blood samples were collected for adiponectin measurements and total RNA was isolated from plantaris and soleus muscles to measure by RT-qPCR adiponectin receptor 1 and adiponectin mRNA expression level. Results: MIT and HIT groups had reduced adiponectin protein levels in serum and the plantaris muscle, but not changes in adiponectin protein were observed in the soleus muscle. No significant differences in Adiponectin receptor 1 (AdipoR1) gene expression were observed following intense or moderate exercise in either muscle group studied. Conclusions: Our study shows that decreasing levels of circulating adiponectin is a result of physical exercise and should not be generalized as a predictive marker of disease.

High-Dose Astaxanthin Supplementation Suppresses Antioxidant Enzyme Activity during Moderate-Intensity Swimming Training in Mice

Exercise-induced reactive oxygen and nitrogen species are increasingly considered as beneficial health promotion. Astaxanthin (ASX) has been recognized as a potent antioxidant suitable for human ingestion. We investigated whether ASX administration suppressed antioxidant enzyme activity in moderate-intensity exercise. Seven-week-old male C57BL/6 mice (n = 8/group) were treated with ASX (5, 15, and 30 mg/kg BW) combined with 45 min/day moderate-intensity swimming training for four weeks. Results showed that the mice administrated with 15 and 30 mg/kg of ASX decreased glutathione peroxidase, catalase, malondialdehyde, and creatine kinase levels in plasma or muscle, compared with the swimming control group. Beyond that, these two (15 and 30 mg/kg BW) dosages of ASX downregulated gastrocnemius muscle erythroid 2p45 (NF-E2)-related factor 2 (Nrf2). Meanwhile, mRNA of Nrf2 and Nrf2-dependent enzymes in mice heart were also downregulated in the ASX-treated groups. However, the mice treated with 15 or 30 mg/kg ASX had increased constitutive nitric oxidase synthase and superoxide dismutase activity, compared with the swimming and sedentary control groups. Our findings indicate that high-dose administration of astaxanthin can blunt antioxidant enzyme activity and downregulate transcription of Nrf2 and Nrf2-dependent enzymes along with attenuating plasma and muscle MDA.

Distinct patterns of skeletal muscle mitochondria fusion, fission and mitophagy upon duration of exercise training

AIM

Healthy ageing interventions encompass regular exercise to prevent mitochondrial dysfunction, key player in sarcopenia pathogenesis. Mitochondrial biogenesis has been well documented, but mitochondrial remodelling in response to exercise training is poorly understood. Here we investigated fusion, fission and mitophagy before and after an exercise intervention in older adults.

METHODS

Skeletal muscle biopsies were collected from 22 healthy sedentary men and women before and after 4 months of supervised training. Eight lifelong trained age- and gender-matched volunteers served as positive controls. Transmission electron microscopy was used to estimate mitochondrial content. Western blotting and qRT-PCR were used to detect changes in specific proteins and transcripts.

RESULTS

After intervention, mitochondrial content increased to levels of controls. While enhancement of fusion was prevalent after intervention, inhibition of fission and increased mitophagy were dominant in controls. Similarly to PARKIN, BCL2L13 content was higher in controls. The observed molecular adaptations paralleled long-term effects of training on physical fitness, exercise efficiency and oxidative capacity.

CONCLUSIONS

This study describes distinct patterns of molecular adaptations in human skeletal muscle under chronic exercise training. After 16 weeks of exercise, the pattern was dominated by fusion to increase mitochondrial content to the metabolic demands of exercise. In lifelong exercise, the pattern was dominated by mitophagy synchronized with increased fusion and decreased fission, indicating an increased mitochondrial turnover. In addition to these temporally distinct adaptive mechanisms, this study suggests for the first time a specific role of BCL2L13 in chronic exercise that requires constant maintenance of mitochondrial quality.

Chronic exercise impairs nitric oxide pathway in rabbit carotid and femoral arteries

KEY POINTS

Some of the beneficial effects of exercise in preventing vascular related diseases are mediated by the enhancement of endothelial function where the role of nitric oxide (NO) is well documented, although the relevance of calcium activated potassium channels is not fully understood. The impact of oxidative stress induced by training on endothelial function remains to be clarified. By evaluating different endothelial vasodilator pathways on two vascular beds in a rabbit model of chronic exercise, we found a decreased NO bioavailability and endothelial nitric oxide synthase expression in both carotid and femoral arteries. Physical training induced carotid endothelial dysfunction as a result of an increase in oxidative stress and a reduction in superoxide dismutase expression. In the femoral artery, the lower production of NO was counteracted by an increased participation of large conductance calcium activated potassium channels, preventing endothelial dysfunction.

ABSTRACT

The present study aimed to evaluate the effects of chronic exercise on vasodilator response in two different arteries. Rings of carotid and femoral arteries from control and trained rabbits were suspended in organ baths for isometric recording of tension. Endothelial nitric oxide synthase (eNOS), Cu/Zn and Mn-superoxide dismutase (SOD), and large conductance calcium activated potassium (BKCa) channel protein expression were measured by western blotting. In the carotid artery, training reduced the relaxation to ACh (10^-9 to 3 × 10^-6  m) that was reversed by N-acetylcysteine (10^-3  m). l-NAME (10^-4  m) reduced the relaxation to ACh in both groups, although the effect was lower in the trained group (in mean ± SEM, 39 ± 2% vs. 28 ± 3%). Physical training did not modify the relaxation to ACh in femoral arteries, although the response to l-NAME was lower in the trained group (in mean ± SEM, 41 ± 5% vs. 17 ± 2%). Charybdotoxin (10^-7  m) plus apamin (10^-6  m) further reduced the maximal relaxation to ACh only in the trained group. The remaining relaxation in both carotid and femoral arteries was abolished by KCl (2 × 10^-2  m) and BaCl₂ (3 × 10^-6  m) plus ouabain (10^-4  m) in both groups. Physical training decreased eNOS expression in both carotid and femoral arteries and Cu/Zn and Mn-SOD expression only in the carotid artery. BKCa channels were overexpressed in the trained group in the femoral artery. In conclusion, chronic exercise induces endothelial dysfunction in the carotid artery as a result of oxidative stress. In the femoral artery, it modifies the vasodilator pathways, enhancing the participation of BKCa channels, thus compensating for the impairment of NO-mediated vasodilatation.

Obstructive Sleep Apnea and Sleep Architecture in Adolescents With Severe Obesity: Effects of a 9-Month Lifestyle Modification Program Based on Regular Exercise and a Balanced Diet

STUDY OBJECTIVES

Physical exercise and lifestyle modification are recognized as adjunct therapy for obstructive sleep apnea (OSA) in overweight adults. The objectives of this study were to investigate the effects of long-term physical exercise combined with a balanced diet on sleep architecture, sleep duration, and OSA in adolescents with severe obesity.

METHODS

This interventional study was conducted in a nursing institution. Participants were aged 14.6 ± 1.2 years with obesity (body mass index (BMI) = 40.2 ± 6.5 kg/m2). At admission and at 9 months, participants underwent ambulatory polysomnography and incremental maximal exercise testing to determine cardiorespiratory fitness.

RESULTS

Twenty-four subjects completed the study. Analyses were performed on the whole population and on a subgroup of subjects with OSA (OSA-subgroup). OSA, defined as obstructive apnea-hypopnea index (OAHI) ≥ 2 events/h, was diagnosed in 58.3% of the population. OAHI was only associated with fat mass in males (r = .75, P < .05). At 9 months postintervention, weight loss (-11.1 kg, P < .0001) and improved cardiorespiratory fitness (VO2peak: +4.9 mL/min/kg, P < .001) were found in the whole population. Sleep duration was increased (+34 minutes, P < .05) and sleep architecture was changed with an increase of rapid eye movement sleep (+2.5%, P < .05) and a decrease of stage N3 sleep (-3.1%, P < .001). Similar results were found in the OSA subgroup. However, OAHI remained unchanged (P = .18).

CONCLUSIONS

A combination of supervised aerobic exercise and a balanced diet led to weight loss, improved aerobic capacity, and modified sleep architecture without changes in OSA.

COMMENTARY

A commentary on this article appears in this issue on page 907.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov, Title: Exercise and Venous Compression on Upper Airway Resistance in Obese Teenagers With OSA (OBESOMAC), URL: https://clinicaltrials.gov/ct2/show/NCT02588469, Identifier: NCT02588469.

Potentiation of Ecstasy-induced hyperthermia and FAT/CD36 expression in chronically exercised animals

Fatal hyperthermia as a result of 3,4-methylenedioxymethamphetamine (MDMA) use involves non-esterified free fatty acids (NEFA) and the activation of mitochondrial uncoupling proteins (UCP). NEFA gain access into skeletal muscle via specific transport proteins, including fatty acid translocase (FAT/CD36). FAT/CD36 expression is known to increase following chronic exercise. Previous studies have demonstrated the essential role of NEFA and UCP3 in MDMA-induced hyperthermia. The aims of the present study were to use a chronic exercise model (swimming for two consecutive hours per day, five days per wk for six wk) to increase FAT/CD36 expression in order to: 1) determine the contribution of FAT/CD36 in MDMA (20 mg/kg, s.c.)-mediated hyperthermia; and 2) examine the effects of the FAT/CD36 inhibitor, SSO (sulfo-N-succinimidyl oleate), on MDMA-induced hyperthermia in chronic exercise and sedentary control rats. MDMA administration resulted in hyperthermia in both sedentary and chronic exercise animals. However, MDMA-induced hyperthermia was significantly potentiated in the chronic exercise animals compared to sedentary animals. Additionally, chronic exercise significantly reduced body weight, increased FAT/CD36 protein expression levels and reduced plasma NEFA levels. The FAT/CD36 inhibitor, SSO (40 mg/kg, ip), significantly attenuated the hyperthermia mediated by MDMA in chronic exercised but not sedentary animals. Plasma NEFA levels were elevated in sedentary and exercised animals treated with SSO prior to MDMA suggesting attenuation of NEFA uptake into skeletal muscle. Chronic exercise did not alter skeletal muscle UCP3 protein expression levels. In conclusion, chronic exercise potentiates MDMA-mediated hyperthermia in a FAT/CD36 dependent fashion.

Association of physical activity with cognition, metacognition and academic performance in children and adolescents: a protocol for systematic review and meta-analysis

INTRODUCTION

Schools provide a relevant context for improving children's and adolescents' physical and mental health by increasing physical activity during school hours and/or beyond. The interest in the relationship between physical activity programmes and cognition during development has recently increased, with evidence suggesting a positive association. We present a protocol of systematic reviews and meta-analysis of intervention studies that, by determining the effects of chronic physical exercise on children's and adolescents' cognitive and metacognitive functions, cognitive life skills, academic behaviours and achievement, aims to ensure procedural objectivity and transparency, and maximise the extraction of relevant information to inform policy development.

METHODS

This protocol is guided by Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols (PRISMA-P) and by the Cochrane Collaboration Handbook. Databases to be utilised for a thorough selection of the pertinent literature are MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Science, PsycINFO and ERIC. Selection is proposed to encompass an international and a national publication level, with inclusion of experimental studies written in English or in Spanish, respectively. Also, relevant references included in the selected studies will be considered suitable for review as supplemental sources.We present an integrated approach to the methodological quality assessment of the selected studies, including the Jadad Scale for the assessment of the quality of randomised controlled trials and the Quality Assessment Tool for Quantitative Studies for pre-post studies and non-randomised controlled trials. The pre-post interventions mean differences will be the primary indicator of the intervention outcome.

STATISTICAL ANALYSIS

A subgroup analysis is proposed based on cognitive functions and their neural correlates, metacognitive functions and cognitive life skills, academic achievement areas and academic behaviours.

TRIAL REGISTRATION NUMBER

PROSPERO CRD42015029913.

Effects of moderate- and high-intensity chronic exercise on brain-derived neurotrophic factor expression in fast and slow muscles

INTRODUCTION

Brain-derived neurotrophic factor (BDNF) protein expression is sensitive to cellular activity. In the sedentary state, BDNF expression is affected by the muscle phenotype.

METHODS

Eighteen Wistar rats were divided into the following 3 groups: sedentary (S); moderate-intensity training (MIT); and high-intensity training (HIT). The training protocol lasted 8 weeks. Forty-eight hours after training, total RNA and protein levels in the soleus and plantaris muscles were obtained.

RESULTS

In the plantaris, the BDNF protein level was lower in the HIT than in the S group (P < 0.05). A similar effect was found in the soleus (without significant difference). In the soleus, higher Bdnf mRNA levels were found in the HIT group (P < 0.001 vs. S and MIT groups). In the plantaris muscle, similar Bdnf mRNA levels were found in all groups.

CONCLUSIONS

These results indicate that high-intensity chronic exercise reduces BDNF protein level in fast muscles and increases Bdnf mRNA levels in slow muscles.

Autophagic adaptation is associated with exercise-induced fibre-type shifting in skeletal muscle

AIM

Acute exercise is known to activate autophagy in skeletal muscle. However, little is known about how basal autophagy in skeletal muscle adapts to chronic exercise. In the current study we aim to, firstly, examine whether long-term habitual exercise alters the basal autophagic signalling in plantaris muscle and, secondly, examine the association between autophagy and fibre-type shifting.

METHODS

Adult female Sprague-Dawley rats aged 2 months were randomly assigned to control and exercise groups. Animals in exercise group were kept in cages equipped with free access running wheels to perform habitual exercise for 5 months. Animals in the control group were caged in the absence of running wheels. Animals were sacrificed after the 5-month experimental period. Plantaris muscle tissues were harvested for analysis.

RESULTS

We showed that long-term habitual exercise enhanced basal autophagy, but without altering expressions of autophagy proteins in plantaris muscle. Interestingly, sirtuin protein, a possible regulator of autophagy, was upregulated in plantaris muscle. Furthermore, we suspected that different types of muscle fibre adapted to chronic exercise in different ways. Long-term habitual exercise resulted in fibre-type shifting from type IIX to IIA in both gastrocnemius muscle and plantaris muscle. Intriguingly, our analysis demonstrated that LC3-II protein abundance is positively correlated with the proportion of type IIA fibre whereas it was negatively correlated with the proportion of type IIX fibre in plantaris muscle. PGC-1α protein abundance was positively associated with the proportion of type IIA fibre and LC3-II in plantaris muscle.

CONCLUSION

These results suggest that basal autophagy is enhanced in plantaris muscle after long-term habitual exercise and associated with fibre-type shifting.

Chronic exercise improves repeated restraint stress-induced anxiety and depression through 5HT1A receptor and cAMP signaling in hippocampus

[Purpose]

Mood disorders such as anxiety and depression are prevalent psychiatric illness, but the role of 5HT1A in the anti-depressive effects of exercise has been rarely known yet. We investigated whether long-term exercise affected a depressive-like behavior and a hippocampal 5HT1A receptor-mediated cAMP/PKA/CREB signaling in depression mice model.

[Methods]

To induce depressive behaviors, mice were subjected to 14 consecutive days of restraint stress (2 hours/day). Depression-like behaviors were measured by forced swimming test (TST), and anxiety-like behavior was assessed by elevated plus maze (EPM). Treadmill exercise was performed with 19 m/min for 60 min/day, 5 days/week from weeks 0 to 8. Restraint stress was started at week 6 week and ended at week 8. To elucidate the role of 5HT1A in depression, the immunoreactivities of 5HT1A were detected in hippocampus using immunohistochemical technique.

[Results]

Chronic/repeated restraint stress induced behavioral anxiety and depression, such as reduced time and entries in open arms in EPM and enhanced immobility time in FST. These anxiety and depressive behaviors were ameliorated by chronic exercise. Also, these behavioral changes were concurrent with the deficit of 5HT1A and cAMP/PKA/CREB cascade in hippocampus, which was coped with chronic exercise.

[Conclusion]

These results suggest that chronic exercise may improve the disturbance of hippocampal 5HT1A-regulated cAMP/PKA/CREB signaling in a depressed brain, thereby exerting an antidepressive action.