Treadmill running prevents age-related memory deficit and alters neurotrophic factors and oxidative damage in the hippocampus of Wistar rats

Effect of exercise detraining in cognitive functions of older adults: A systematic review

OBJECTIVE

Provide a synthesis of the current literature about the effects of detraining on cognitive functions in older adults.

METHODS

The PICOS acronym strategy was performed in PubMed/MEDLINE, Web of Science, Cochrane Library and PsycINFO database. The Preferred Reporting Items for Systematic Review and Meta-Analyses statement had been followed in the present study, in which the search was conducted on October 2023. The study selection consisted in original articles including older adults, detraining after training exercise period, use of tests or scales to measure cognitive function. The Downs and Black checklist had been used to assess the studies quality. Sample characteristics, type of previous training, detraining period, cognitive functions measurements and main results were extracted by 2 investigators.

RESULTS

From 1927 studies, 12 studies were included, being 11 studies identified via systematic research, and 1 study by citation search. Older adults, ranged from 60 to 87 years old, were assessed after detraining. The cognitive functions most evaluated were global cognition and executive functions. One study evaluated both cognitive outcome and cerebral blood flow. Most of the studies demonstrated a decline in the cognitive function after detraining.

CONCLUSION

Exercise detraining period, ranging from 10 days to 16 weeks, can effect negatively the cognitive function in older adults.

Long-term voluntary running improves cognitive ability in developing mice by modulating the cholinergic system, antioxidant ability, and BDNF/PI3K/Akt/CREB pathway

Moderate physical exercise has positive effects on memory. The present study aimed to investigate the impact of long-term exercise on spatial memory in developing mice, as well as its association with the cholinergic system, antioxidant activities, apoptosis factor, and BDNF/PI3K/Akt/CREB pathway in the brain. In this study, Y maze and Novel object recognition (NOR) tests were employed to assess the impact of long-term voluntary exercise on memory. The cholinergic system, antioxidant activities, and apoptosis factors in the brain were quantified using Elisa. Additionally, western blot analysis was conducted to determine the expression of relevant proteins in the BDNF/PI3K/Akt/CREB pathway. The findings demonstrated that prolonged voluntary wheel running exercise enhanced memory in developing mice, concomitant with increased catalase (CAT) activity and decreased malondialdehyde (MDA) levels in the brain. Moreover, it could also increase the hippocampal acetylcholine (ACh) content and suppress the expression of neuronal apoptosis protein. Additionally, exercise also upregulated the expression of brain-derived neurotrophic factor (BDNF), tropomyosin receptor kinase B (TrkB), phosphoinositide 3 kinases (PI3K), Akt, cAMP response element-binding protein (CREB), and phosphorylated cAMP response element-binding protein (p-CREB) in the hippocampus. These findings suggest that long-term voluntary wheel running exercise improves the spatial memory of developing mice by modulating the cholinergic system, antioxidant activities, apoptosis factors, and activating the BDNF/PI3K/Akt/CREB pathway.

A study on the impact of acute exercise on cognitive function in Alzheimer's disease or mild cognitive impairment patients: A narrative review

This narrative review follows the JBI approach and comprehensively explores the effects and mechanisms of acute exercise on cognitive function in Alzheimer's disease (AD) and Mild cognitive impairment (MCI) patients. The results showed that the combination of acute exercise and cognitive training improved the cognitive function of AD patients better than aerobic exercise or resistance training alone. For patients with MCI, moderate intensity acute aerobic exercise and resistance exercise were beneficial to enhance Inhibitory control (IC), but high-intensity acute exercise was adverse to improve IC; Brain-derived neurotrophic factor (BDNF) and Insulin-like growth factor 1 (IGF-1) may assume the potential mediating mechanism of acute exercise on cognitive function in AD and MCI patients, but more research is needed to further confirm this mechanism.

The effects of moderate-intensity aerobic exercise on cognitive function in individuals with stroke-induced mild cognitive impairment: a randomized controlled pilot study

OBJECTIVE

To assess the impact of moderate-intensity aerobic exercise on working memory in stroke-induced mild cognitive impairment (MCI).

DESIGN

Randomized, double-blind controlled study.

SUBJECTS AND METHODS

Twenty MCI patients from the Fifth Affiliated Hospital of Guangzhou Medical University (December 2021 to February 2023), aged 34-79, 2-12 months post-stroke, were divided into an experimental group (EG) and a control group (CG), each with 10 participants. The EG underwent standard rehabilitation plus 40 minutes of aerobic exercise, while the CG received only standard therapy, 5 times weekly for 2 weeks. Working memory was tested using the n-back task, and overall cognitive function was measured with the MOCA and MMSE Scales before and after the intervention.

RESULTS

The EG showed higher 3-back correctness (71.80 ± 14.53 vs 56.50 ± 13.66), MOCA scores (27.30 ± 1.57 vs 24.00 ± 3.13), and improved visuospatial/executive (4.60 ± 0.52 vs 3.30 ± 1.06) and delayed recall (4.30 ± 0.82 vs 3.00 ± 1.56) on the MOCA scale compared with the CG.

CONCLUSION

Moderate-intensity aerobic exercise may enhance working memory, visuospatial/executive, and delayed recall functions in stroke-induced MCI patients.

Unraveling the Influence of Litter Size, Maternal Care, Exercise, and Aging on Neurobehavioral Plasticity and Dentate Gyrus Microglia Dynamics in Male Rats

This study explores the multifaceted influence of litter size, maternal care, exercise, and aging on rats' neurobehavioral plasticity and dentate gyrus microglia dynamics. Body weight evolution revealed a progressive increase until maturity, followed by a decline during aging, with larger litters exhibiting lower weights initially. Notably, exercised rats from smaller litters displayed higher body weights during the mature and aged stages. The dentate gyrus volumes showed no significant differences among groups, except for aged sedentary rats from smaller litters, which exhibited a reduction. Maternal care varied significantly based on litter size, with large litter dams showing lower frequencies of caregiving behaviors. Behavioral assays highlighted the detrimental impact of a sedentary lifestyle and reduced maternal care/large litters on spatial memory, mitigated by exercise in aged rats from smaller litters. The microglial dynamics in the layers of dentate gyrus revealed age-related changes modulated by litter size and exercise. Exercise interventions mitigated microgliosis associated with aging, particularly in aged rats. These findings underscore the complex interplay between early-life experiences, exercise, microglial dynamics, and neurobehavioral outcomes during aging.

Multifunctional Two-Dimensional Bi2Se3 nanodisks as a Non-Inflammatory photothermal agent for glioma treatment

Photothermal therapy (PTT) has gained widespread attention due to its significant advantages, such as noninvasiveness and ability to perform laser localization. However, PTT usually reaches temperatures exceeding 50 °C, which causes tumor coagulation necrosis and unfavorable inflammatory reactions, ultimately decreasing its efficacy. In this study, multifunctional two-dimensional Bi2Se3 nanodisks were synthesized as noninflammatory photothermal agents for glioma therapy. The Bi2Se3 nanodisks showed high photothermal stability and biocompatibility and no apparent toxicology. In addition, in vitro and in vivo studies revealed that the Bi2Se3 nanodisks effectively ablated gliomas at relatively low concentrations and inhibited tumor proliferation and migration. Moreover, the multienzymatic activity of the Bi2Se3 nanodisks inhibited the PTT-induced inflammatory response through their high ability to scavenge reactive oxygen species. Finally, the Bi2Se3 nanodisks demonstrated computed tomography capabilities for integrating diagnosis and treatment. These findings suggest that multifunctional Bi2Se3 nanodisk nanozymes can enable more effective cancer therapy and noninflammatory PTT.

Brain-Derived Neurotrophic Factor in Pediatric Acquired Brain Injury and Recovery

We review emerging preclinical and clinical evidence regarding brain-derived neurotrophic factor (BDNF) protein, genotype, and DNA methylation (DNAm) as biomarkers of outcomes in three important etiologies of pediatric acquired brain injury (ABI), traumatic brain injury, global cerebral ischemia, and stroke. We also summarize evidence suggesting that BDNF is (1) involved in the biological embedding of the psychosocial environment, (2) responsive to rehabilitative therapies, and (3) potentially modifiable. BDNF's unique potential as a biomarker of neuroplasticity and neural repair that is reflective of and responsive to both pre- and post-injury environmental influences separates it from traditional protein biomarkers of structural brain injury with exciting potential to advance pediatric ABI management by increasing the accuracy of prognostic tools and informing clinical decision making through the monitoring of therapeutic effects.

Decreased Hippocampal Neurogenesis in Aged Male Wistar Rats Is Not Associated with Memory Acquisition in a Water Maze

Brain aging is associated with a progressive decrease in learning abilities, memory, attention, decision making, and sensory perception. Age-related cognitive disturbances may be related to a decrease in the functional capacities of the hippocampus. This brain region is essential for learning and memory, and the lifelong neurogenesis occurring in the subgranular zone of the dentate gyrus may be a key event mediating the mnemonic functions of the hippocampus. In the present study, we investigated whether age-related changes in hippocampal neurogenesis are associated with learning and memory disturbances. Four- and 24-month-old rats were trained to find a hidden platform in a water maze. Though the older group showed higher latency to search the platform as compared to the younger group, both groups learned the task. However, the density of proliferating (PCNA-positive), differentiating (Dcx-positive), and new neurons (pre-labeled BrdU-positive) was significantly lower in the hippocampus of aged rats as compared to young ones. This inhibition of neurogenesis could be related to increased local production of nitric oxide since the density of neurons expressing neuronal NO-synthase was higher in the aged hippocampus. Thus, we can suggest that an age-related decrease in neurogenesis is not directly associated with place learning in aged rats.

The role of IGF-1 in exercise to improve obesity-related cognitive dysfunction

Obesity is an important factor that threatens human health. The occurrence of many chronic diseases is related to obesity, and cognitive function decline often occurs with the onset of obesity. With the further prevalence of obesity, it is bound to lead to a wider range of cognitive dysfunction (ORCD). Therefore, it is crucial to suppress ORCD through intervention. In this regard, exercise has been shown to be effective in preventing obesity and improving cognitive function as a non-drug treatment. There is sufficient evidence that exercise has a regulatory effect on a growth factor closely related to cognitive function-insulin-like growth factor 1 (IGF-1). IGF-1 may be an important mediator in improving ORCD through exercise. This article reviews the effects of obesity and IGF-1 on cognitive function and the regulation of exercise on IGF-1. It analyzes the mechanism by which exercise can improve ORCD by regulating IGF-1. Overall, this review provides evidence from relevant animal studies and human studies, showing that exercise plays a role in improving ORCD. It emphasizes the importance of IGF-1, which helps to understand the health effects of exercise and promotes research on the treatment of ORCD.

Exerkines and redox homeostasis

Exercise physiology has gained increasing interest due to its wide effects to promote health. Recent years have seen a growth in this research field also due to the finding of several circulating factors that mediate the effects of exercise. These factors, termed exerkines, are metabolites, growth factors, and cytokines secreted by main metabolic organs during exercise to regulate exercise systemic and tissue-specific effects. The metabolic effects of exerkines have been broadly explored and entail a promising target to modulate beneficial effects of exercise in health and disease. However, exerkines also have broad effects to modulate redox signaling and homeostasis in several cellular processes to improve stress response. Since redox biology is central to exercise physiology, this review summarizes current evidence for the cross-talk between redox biology and exerkines actions. The role of exerkines in redox biology entails a response to oxidative stress-induced pathological cues to improve health outcomes and to modulate exercise adaptations that integrate redox signaling.

Liquid exfoliation of ultrasmall zirconium carbide nanodots as a noninflammatory photothermal agent in the treatment of glioma

Photothermal therapy (PTT), like other clinical translational tumor ablation techniques, requires a temperature increase above 50 °C to cause necrosis and death of tumor cells. Although the tumor can be eliminated rapidly by PTT, the inflammatory response is triggered by the large amounts of released reactive oxygen species (ROS). Therefore, liquid exfoliation was used to create ultrasmall zirconium carbide nanodots (NDs) with an average diameter of approximately 4.5 nm as noninflammatory/anti-inflammatory photosensitizers for PTT of glioma. Ultrasmall ZrC NDs showed excellent photothermal stability and biocompatibility but no obvious toxicity. Moreover, the ultrasmall ZrC NDs effectively ablated glioma at relatively low concentrations and inhibited tumor migration and proliferation in vitro and in vivo. Furthermore, the excellent ROS-scavenging ability of ultrasmall ZrC NDs suppressed the inflammatory response to PTT. Intriguingly, we found that ZrC had the capability of performing CT imaging. We demonstrated that the ultrasmall ZrC NDs created in this study could effectively and safely treat glioma without inflammation.

Aerobic Training and Circulating Neurotrophins in Alzheimer's Disease Patients: A Controlled Trial

OBJECTIVE

to verify the effects of aerobic exercise training in circulating BDNF, VEGF₁₆₅ and IGF-1 plasma levels and cognitive function in Alzheimer's Disease (AD) patients.

METHODS

34 AD patients participated in the study, divided in two groups: Control Group (CG; n = 16) and Training Group (TG; n = 18 - Moderate aerobic training on the treadmill, three times a week, for 12 weeks). BDNF, VEGF_165, and IGF-1 plasma levels were considered as a primary outcome. Secondary outcomes included cognitive functions and aerobic fitness.

RESULTS

After 12 weeks, maintenance of executive functioning in the TG was found, yet no significant changes on circulating neurotrophins levels were identified. For aerobic fitness, there was an increment in TG group.

CONCLUSION

Twelve weeks of aerobic training were neither effective in improving cognitive functioning significantly, nor influential on circulating neurotrophins levels in AD patients.

Treadmill running and Levisticum Officinale extract protect against LPS-induced memory deficits by modulating neurogenesis, neuroinflammation and oxidative stress

Neuroinflammation plays an essential role in the pathogenesis of Alzheimer's disease. The preventive effect of physical exercise on attenuating neuroinflammation has not been completely defined. Levisticum officinale is known as a medicinal plant with antioxidant and anti-inflammatory properties. The current study was designed to investigate the neuroprotective impacts of treadmill running and Levisticum officinale on lipopolysaccharide (LPS)-induced learning and memory impairments and neuroinflammation in rats. Male Wistar rats ran on a treadmill and/or were pretreated with Levisticum officinale extract at a dose of 100 mg/kg for a week. Then, rats received intraperitoneal injection of LPS at a dose of 1 mg/kg. Treadmill running and/or treatment of extract lasted three more weeks. Behavioral, molecular, biochemical and immunohistochemical assessments were carried out after the end of the experiment. LPS administration resulted in spatial learning and memory impairments along with increased mRNA expression of interleukin-6 and malondialdehyde levels, as well as decreased superoxide dismutase activity and neurogenesis in the hippocampus. Moreover, treadmill running for four weeks, alone and in combination with Levisticum officinale extract attenuated spatial learning and memory deficits, decreased the mRNA expression of interleukin-6 and malondialdehyde levels, and enhanced superoxide dismutase activity and neurogenesis in the hippocampus. In conclusion, the advantageous effects of running exercise and Levisticum officinale extract on LPS-induced memory impairments are possibly due to the antioxidant and anti-inflammatory activity and enhancing neurogenesis.

Synthetic Mono-Carbonyl Curcumin Analogues Attenuate Oxidative Stress in Mouse Models

Alzheimer’s disease is the commonest form of dementia associated with short-term memory loss and impaired cognition and, worldwide, it is a growing health issue. A number of therapeutic strategies have been studied to design and develop an effective anti-Alzheimer drug. Curcumin has a wide spectrum of biological properties. In this regard, the antioxidant potentials of mono-carbonyl curcumin analogues (h1−h5) were investigated using in vitro antioxidant assays and hippocampal-based in vivo mouse models such as light−dark box, hole board, and Y-maze tests. In the in vitro assay, mono-carbonyl curcumin analogues h2 and h3 with methoxy and chloro-substituents, respectively, showed promising 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2, 2′-azinobis-3-ethylbenzothiazo-line-6-sulfonate (ABTS) free radical scavenging activities. In the in vivo studies, scopolamine administration significantly (p < 0.001) induced oxidative stress and memory impairment in mice, in comparison to the normal control group. The pretreatment with mono-carbonyl curcumin analogues, specifically h2 and h3, significantly decreased (123.71 ± 15.23 s (p < 0.001), n = 8; 156.53 ± 14.13 s (p < 0.001), n = 8) the duration of time spent in the light chamber and significantly enhanced (253.95 ± 19.05 s (p < 0.001), n = 8, and 239.57 ± 9.98 s (p < 0.001), n = 8) the time spent in the dark compartment in the light−dark box arena. The numbers of hole pokings were significantly (p < 0.001, n = 8) enhanced in the hole board test and substantially increased the percent spontaneous alternation performance (SAP %) in the Y-maze mouse models in comparison to the stress control group. In the biomarker analysis, the significant reduction in the lipid peroxidation (MDA) level and enhanced catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) activities in the brain hippocampus reveal their antioxidant and memory enhancing potentials. However, further research is needed to find out the appropriate mechanism of reducing oxidative stress in pathological models.

Investigation of Antistress and Antidepressant Activities of Synthetic Curcumin Analogues: Behavioral and Biomarker Approach

Depression is a serious psychiatric disorder that affects millions of individuals all over the world, thus demanding special attention from researchers in order to investigate its effective remedies. Curcumin, along with its synthetic derivatives, is recognized for its incredible pharmacological activities. In this study, methyl, methoxy and chloro-substituent synthetic curcumin analogues C1-C3 were respectively tested for free radical-scavenging activity. Behavioral studies were performed using chemical-induced and swimming endurance tests as stress models, and forced swim tests (FSTs) and tail suspension tests (TSTs) as depression mice models. Biochemical examinations were performed after a scopolamine-induced stress model by decapitating the mice, and brain tissues were isolated for biochemical assessment of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and malondialdehyde (MDA). The curcumin analogue C2 exhibited higher DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis-3-ethylbenzothiazo-line-6-sulphonate) free radical-scavenging potential, having IC50 values of 45.18 µg/mL and 62.31 µg/mL, respectively, in comparison with reference curcumin and tocopherol. In the chemical-induced test, C2 (80.17%), C3 (72.79%) and C1 (51.85%) revealed higher antistress responses by significantly reducing the number of writhes, whereas the immobility time was significantly reduced by C2 and C3 in the swimming endurance test, indicating excellent antistress potential. Similarly, C2 and C3 significantly reduced the immobility times in FST and TST, demonstrating their antidepressant properties. The biomarkers study revealed that these compounds significantly enhanced hippocampus CAT, SOD and GSH, and reduced MDA levels in the scopolamine-induced stress mice model. These findings suggest the potential of curcumin analogues (C2 and C3) as antistress and antidepressant agents.

Swimming exercise prevents hippocampal dendritic spine changes and memory loss caused by aging: An application of a new semi-automated spine analysis software

Dendritic spines are small, ratchet-like protrusions on neuronal dendrites that form synapses for receiving neuronal messages. Dendritic spine morphology is associated with synapse function. If neurons degrade or are damaged, the spine morphology of neurons changes. Given that most commercially available spine analysis software is expensive and complex, this study investigated a semi-automated spine analysis software, CTSpine, and used previously published data to verify the accuracy of the analysis results of this software. We also applied CTSpine to understand whether aging causes alterations in the hippocampal spine morphology and whether physical exercise can impede dendritic spine changes in 20 male Sprague Dawley rats. The spines of pyramidal cells in the hippocampal Cornu Ammonis 1 (CA1) region in the aging group were more enriched in filopodium type pattern than those in the control group, whereas the spines of the exercised aging group showed a similar pattern to that of the control. No significant changes were observed in neuronal dendritic spines in other hippocampal regions. However, long-term hippocampal memory was considerably decreased in the aging group, which was reversed to some extent in the exercised aging group. CTSpine, a self-developed semi-automatic spine analysis software, showed results similar to those noted in published data and can be effectively applied to the study of dendritic patterns, including neurodevelopment and disease.

Effects of Treadmill Exercise on Mitochondrial DNA Damage and Cardiomyocyte Telomerase Activity in Aging Model Rats Based on Classical Apoptosis Signaling Pathway

In order to explore the effect of treadmill exercise on mitochondrial DNA damage and myocardial telomerase activity in aging model rats based on the classical apoptosis signaling pathway, a total of 36 clean-grade male SD rats are selected. After modeling, the rats are randomly divided into groups, namely, control and 3 times/w and 6 times/w exercise rats, with 12 rats in each group. After the rats of each group are modeled, the myocardial tissue and cells are collected, the apoptosis of myocardial cells is detected by TUNEL method, and the protein expressions of Bax and Bcl-2 in myocardial tissue are detected by western blotting. The mtDNA content of the control rats is the highest, which is significantly higher than that of the exercise group ( $P<0.05$ ); the expression of mtDNA content in the heart of the rats exercising 3 times/w is significantly higher than that of the rats exercising 6 times/w ( $P<0.05$ ); cardiomyocyte apoptosis AI value, Bcl-2, and Bax expressions of the control rats is the highest and significantly higher than those in the exercise group ( $P<0.05$ ); Bcl-2/Bax in the control rats is the lowest and is significantly lower than that in the exercise group ( $P<0.05$ ). The AI value, Bcl-2, and Bax expression of myocardial cell apoptosis in 3 times/w exercise rats are significantly higher than those in 6 times/w exercise rats ( $P<0.05$ ); Bcl-2/Bax of 3 times/w exercise rats is significantly lower than that in 6 times/w exercise rats ( $P<0.05$ ); by observing the rats that completed treadmill exercise, Akt2 protein of 3 times/w exercise rats and 6 times/w exercise rats is observed and analyzed. Compared with the control rats, the expressions of the two proteins are increased in 3 times/w exercise rats and 6 times/w exercise rats, and the upregulation in 6 times/w exercise rats is significantly increased and higher than that in 3 times/w exercise rats ( $P<0.05$ ). For aging rats, treadmill exercise can reduce the body Bcl-2 and Bax values, improve the mitochondrial DNA damage and myocardial cell telomerase activity in aging model rats, and slow down the aging process.

Combination of magnesium supplementation with treadmill exercise improves memory deficit in aged rats by enhancing hippocampal neurogenesis and plasticity: a functional and histological study

This study aimed to investigate the possible ameliorative effects of co-supplementation with Mg²⁺ and treadmill exercise on memory deficit in aged rats. Fifty male albino rats (10 young and 40 aged rats) were divided into 5 groups (10 rats/group): young, aged sedentary, aged exercised, aged Mg²⁺-supplemented, and aged exercised and Mg²⁺-supplemented. Memory was assessed using the Y-maze and novel object recognition tests. Plasma samples were collected for measurement of C-reactive protein (CRP). Subsequently, brain malondialdehyde and catalase levels were measured. Histological and immunohistochemical analyses of the hippocampi were performed. Our results showed impaired memory in aged sedentary rats, with significantly elevated plasma CRP and brain malondialdehyde levels and decreased brain catalase. The hippocampus of aged sedentary rats showed cellular degeneration, downregulation of synaptophysin (SYP) and proliferating cell nuclear antigen (PCNA), and upregulation of glial fibrillary acidic protein (GFAP) and caspase-3. Mg²⁺ supplementation and/or treadmill exercise significantly improved memory tests in aged rats, which could be explained by the upregulation of hippocampal SYP and PCNA expression and downregulation of GFAP and caspase-3 expression with antioxidant and anti-inflammatory mechanisms. The combined therapy had a better effect than both treatments alone, confirming the role of Mg²⁺ supplementation with physical exercise in enhancing age-related memory deficit. Novelty: Magnesium supplementation with treadmill exercise improves memory deficit in aged rats. The possible mechanisms are upregulation of the hippocampal synaptophysin and PCNA, downregulation of GFAP and caspase-3, the antioxidant and anti-inflammatory mechanisms.

The impact of moderate-intensity swimming exercise on learning and memory in aged rats: The role of Sirtuin-1

Objective(s):

The purpose of this study was to evaluate the effect of moderate-intensity swimming exercise on learning and memory by the Morris water maze test. Changes in the expressions of cyclic AMP-response element-binding protein (CREB) and brain-derived neurotrophic factor (BDNF) proteins alternative pathway which were activated by sirtuin-1 (SIRT-1) were investigated.

Materials and Methods:

The study included thirty-two male Sprague-Dawley rats (350-500 g, 11-12 and 15–16 months old). The rats were randomly divided into four groups with 8 rats in each group. The groups were designed as follows: Control-1 (11-12 months), Exercise-1 (11-12 months), Control-2 (15-16 months), Exercise-2 (15-16 months). Moderate-intensity exercise was assigned for 30 min/day, 5 days/week, for the whole training period of 8 weeks.

Results:

There were statistically significant differences between the groups on the third day (P=0.005) when swim speeds increased in the exercise groups. There was a statistically significant difference between Exercise 1 and Exercise 2 groups, the entries in the platform zone decreased in Exercise 2 group (P=0.026). While there were no histopathological findings observed in any group, increased SIRT-1, BNDF, and CREB expressions were seen in exercise groups compared with control groups.

Conclusion:

In aged rats exercising at moderate intensity, increased expression of CREB and BDNF, and SIRT-1 could improve hippocampal-dependent memory.

Differential effects of voluntary and forced exercise trainings on spatial learning ability and hippocampal biomarkers in aged female rats

This study aimed to compare the effects of voluntary and forced exercise trainings on cognitive functions and to evaluate their relationship with hippocampal synaptic proteins, neurotrophic factors and markers of oxidative damage in aged female rats. Aged female rats were randomly assigned to control, voluntary exercise training and forced exercise training groups. Voluntary or forced exercise trainings were performed for 12 weeks. At the end of the training period, cognitive functions of the animals were assessed with Morris water maze (MWM) test. After the behavioral test, hippocampus tissues were taken for the analysis of synaptophysin, acetylcholinesterase (AChE), brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF), malondialdehyde (MDA), protein carbonyl (PC), glutathione (GSH) and superoxide dismutase (SOD). During the MWM test, the number of platform crossings was higher in the voluntary exercise group than in the control group (P < 0.05). In the hippocampus tissue, levels of the synaptophysin, BDNF, NGF and SOD were higher, but MDA levels were lower in the voluntary exercise group than in the control group (P < 0.05). Additionally, hippocampal AChE concentration was higher, but PC levels were lower in the both voluntary and forced exercise groups than in the control group (P < 0.05). In conclusion, voluntary exercise was more effective intervention to improve spatial learning ability in aging process. Increased neurotrophic factors, synaptic proteins, and improved oxidative damage may play a role in these positive effects.

A role for insulin-like growth factor-1 in hippocampal plasticity following traumatic brain injury

Traumatic brain injury (TBI) initiates a constellation of secondary injury cascades, leading to neuronal damage and dysfunction that is often beyond the scope of endogenous repair mechanisms. Cognitive deficits are among the most persistent morbidities resulting from TBI, necessitating a greater understanding of mechanisms of posttraumatic hippocampal damage and neuroplasticity and identification of therapies that improve recovery by enhancing repair pathways. Focusing here on hippocampal neuropathology associated with contusion-type TBIs, the impact of brain trauma on synaptic structure and function and the process of adult neurogenesis is discussed, reviewing initial patterns of damage as well as evidence for spontaneous recovery. A case is made that insulin-like growth factor-1 (IGF-1), a growth-promoting peptide synthesized in both the brain and the periphery, is well suited to augment neuroplasticity in the injured brain. Essential during brain development, multiple lines of evidence delineate roles in the adult brain for IGF-1 in the maintenance of synapses, regulation of neurotransmission, and modulation of forms of synaptic plasticity such as long-term potentiation. Further, IGF-1 enhances adult hippocampal neurogenesis though effects on proliferation and neuronal differentiation of neural progenitor cells and on dendritic growth of newly born neurons. Post-injury administration of IGF-1 has been effective in rodent models of TBI in improving learning and memory, attenuating death of mature hippocampal neurons and promoting neurogenesis, providing critical proof-of-concept data. More studies are needed to explore the effects of IGF-1-based therapies on synaptogenesis and synaptic plasticity following TBI and to optimize strategies in order to stimulate only appropriate, functional neuroplasticity.

Physical Activity vs. Redox Balance in the Brain: Brain Health, Aging and Diseases

It has been proven that physical exercise improves cognitive function and memory, has an analgesic and antidepressant effect, and delays the aging of the brain and the development of diseases, including neurodegenerative disorders. There are even attempts to use physical activity in the treatment of mental diseases. The course of most diseases is strictly associated with oxidative stress, which can be prevented or alleviated with regular exercise. It has been proven that physical exercise helps to maintain the oxidant–antioxidant balance. In this review, we present the current knowledge on redox balance in the organism and the consequences of its disruption, while focusing mainly on the brain. Furthermore, we discuss the impact of physical activity on aging and brain diseases, and present current recommendations and directions for further research in this area.

Nanozymes Regulate Redox Homeostasis in ROS-Related Inflammation

Reactive oxygen species (ROS), in moderate amounts, play an essential role in regulating different physiological functions in organisms. However, increased amounts of ROS may cause oxidative stress and damage to biomolecules, leading to a variety of diseases including inflammation and even cancer. Therefore, ROS scavenging reagents are needed to maintain healthy levels of ROS. With considerable advances in nanotechnology, nanozymes possess SOD or CAT-like activities with outstanding free radical scavenging activity, facile synthesis conditions, and excellent biocompatibility. Based on these extraordinary properties, nanozymes has been used to modulate the redox homeostasis and relieve the ROS-related injury. This has led to the emergence of nanozyme-based therapies. In the current review, we presented recently developed applications of nanozymes to treat ROS-dependent disorders with an emphasis on inflammatory and brain diseases.

Biomarkers for evaluating the effects of exercise interventions in patients with MCI or dementia: A systematic review and meta-analysis

OBJECTIVES

To summarize the biomarkers for evaluating the effects of exercise interventions in patients with cognitive impairment associated with aging, as well as their responses to exercise interventions.

DESIGN

A systematic review and meta-analysis METHODS: We systematically searched different electronic database, including PubMed, Cochrane Central Register of Controlled Trials, Embase, Web of Science, PsycINFO, SPORTDiscus up to April 2020. Clinical controlled trials with exercise interventions in patients with cognitive impairment were included. The main outcomes included all the biomarkers used to evaluate the effects of exercise interventions. If data for certain biomarkers was enough (more than 2 studies), meta-analyses would be performed to estimate the effect sizes by calculating the standard mean differences (SMDs) and 95% confidence intervals (CIs).

RESULTS

Finally, we included 33 articles from 26 trials. The biomarkers included neurotrophic factors, inflammatory factors, oxidative stress markers, neuropathological hallmarks, metabolic biomarkers and genotypes. The meta-analyses indicated that exercise significantly decreased the levels of IL-6 (SMD = -0.45; 95% CI: -0.72, -0.18) and low-density lipoprotein (SMD = -0.26; 95% CI: -0.50, -0.01). Subgroup analyses showed that aerobic exercise also could decrease the levels of TNF-α (SMD = -1.21; 95% CI: -2.29, -0.14). There were some important cognition-related biomarkers which were rarely measured, such as Aβ, tau and IGF-1.

CONCLUSION

Regular exercise showed positive effects on reducing inflammation and regulating lipid metabolism. But the available evidence is limited and more studies with different exercise interventions should be conducted to test the effects of exercise on other important cognition-related biomarkers in patients with cognitive dysfunction.

Idazoxan and Efaroxan Potentiate the Endurance Performances and the Antioxidant Activity of Ephedrine in Rats

Background and objectives: The connections between the imidazoline system and multiple other neurotransmitter systems in the brain (adrenergic, dopaminergic, serotoninergic, glutamatergic, opioid) indicate the complexity of the mechanisms underlying motor activity and behavior. The aim of the present research was to investigate the effects of the combination of ephedrine (EPD) and imidazoline antagonists idazoxan (IDZ) and efaroxan (EFR) on the endurance performance in the treadmill test in rats. Materials and Methods: We used Wistar rats distributed as follows: Group 1 (Control) receiving distilled water 0.3 mL/100 g body weight; Group 2 (EPD) receiving 20 mg/kg ephedrine; Group 3 (EPD + IDZ) receiving 20 mg/kg ephedrine + 3 mg/kg idazoxan; Group 4 (EPD + EFR) receiving 20 mg/kg ephedrine + 1 mg/kg efaroxan. An additional group (C) of animals receiving 0.3 mL/100 g body weight distilled water (but not subjected to effort) was used. Endurance capacity was evaluated using a treadmill running PanLAB assay. The evaluation of the substances’ influence on oxidative stress was performed by spectrophotometric determination of superoxide dismutase (SOD) and glutathione peroxidase (GPX) activity. Results: Treatment with EPD-IDZ and EPD-EFR were correlated with a longer distance traveled on the belt and with a decrease in the necessary electric shocks to motivate the animal to continue running in the forced locomotion test. Additionally, an increase in the activity of antioxidant enzymes was found. Conclusions: Idazoxan and efaroxan potentiated the physical effort-related effects of ephedrine with regard to endurance capacity and antioxidant activity in rats.

Regular aerobic exercise increased VEGF levels in both soleus and gastrocnemius muscles correlated with hippocampal learning and VEGF levels

Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.

Physical exercise improves learning and memory abilities by increasing the levels of several growth factors in the hippocampus. One growth factor, vascular endothelial growth factor (VEGF), is primarily produced in the muscles and not only increases in the periphery during exercise but can also cross the blood-brain barrier. The aim of this study is to investigate the effects of regular aerobic chronic exercise on different types of muscle fibers and the relationships between learning/memory and muscle induced-VEGF. Following a one-week adaptation period, male rats underwent treadmill training at a speed of 8 m/min for 30 min daily, 3 days a week for 6 weeks. Memory functions were evaluated using the Morris water maze. VEGF, superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA) levels were measured in type 1 and type 2 muscle fibers and VEGF levels were also measured in the hippocampus. Exercise positively affected both learning and memory and also increased VEGF levels in both muscle fiber types. Muscle VEGF levels positively correlate with hippocampal learning and hippocampal VEGF levels. Exercise reduced both SOD and MDA levels in type 1 and type 2 muscle fibers, whereas GPx levels decreased only in type 2 muscle fibers. Our findings suggest that regular aerobic exercise elevates VEGF levels and diminishes oxidative stress in both fiber types. Exercise-induced VEGF levels in both type 1 and 2 muscle fibers appear to be associated with the positive effect of exercise on learning and memory function and is accompanied by an increase in VEGF levels in the hippocampus. Further research is needed to elucidate the exact mechanism by which fiber type-specific VEGF mediates hippocampal neurogenesis and angiogenesis.

Long-Term Music Exposure Prevents Age-Related Cognitive Deficits in Rats Independently of Hippocampal Neurogenesis

Cognitive decline appears across aging. While some studies report beneficial effects of musical listening and practice on cognitive aging, the underlying neurobiological mechanisms remain unknown. This study aims to determine whether chronic (6 h/day, 3 times/week) and long-lasting (4-8 months) music exposure, initiated at middle age in rats (15 months old), can influence behavioral parameters sensitive to age effects and reduce age-related spatial memory decline in rats. Spontaneous locomotor, circadian rhythmic activity, and anxiety-like behavior as well as spatial working and reference memory were assessed in 14-month-old rats and then after 4 and 8 months of music exposure (19 and 23 months old, respectively). Spatial learning and reference memory data were followed up by considering cognitive status of animals prior to music exposure (14 months old) given by K-means clustering of individual Z-score. Hippocampal cell proliferation and brain-derived neurotrophic factor (BDNF) level in the hippocampus and frontal cortex were measured. Results show that music exposure differentially rescues age-related deficits in spatial navigation tasks according to its duration without affecting spontaneous locomotor, circadian rhythmic activity, and anxiety-like behavior. Hippocampal cell proliferation as well as hippocampal and frontal cortex BDNF levels was not affected by music across aging. Cognitive improvement by music in aging rats may require distinct neurobiological mechanisms than hippocampal cell proliferation and BDNF.

Effect of ladostigil treatment of aging rats on gene expression in four brain areas associated with regulation of memory

Episodic and spatial memory decline in aging and are controlled by the hippocampus, perirhinal, frontal and parietal cortices and the connections between them. Ladostigil, a drug with antioxidant and anti-inflammatory activity, was shown to prevent the loss of episodic and spatial memory in aging rats. To better understand the molecular effects of aging and ladostigil on these brain regions we characterized the changes in gene expression using RNA-sequencing technology in rats aged 6 and 22 months. We found that the changes induced by aging and chronic ladostigil treatment were brain region specific. In the hippocampus, frontal and perirhinal cortex, ladostigil decreased the overexpression of genes regulating calcium homeostasis, ion channels and those adversely affecting synaptic function. In the parietal cortex, ladostigil increased the expression of several genes that provide neurotrophic support, while reducing that of pro-apoptotic genes and those encoding pro-inflammatory cytokines and their receptors. Ladostigil also decreased the expression of axonal growth inhibitors and those impairing mitochondrial function. Together, these actions could explain the protection by ladostigil against age-related memory decline.

Acute exercise increases circulating IGF-1 in Alzheimer's disease patients, but not in older adults without dementia

OBJECTIVES

Increased Insulin-like growth factor I (IGF-1) has been associated with improvement of cognitive function in response to exercise. Evidences indicate a role for IGF-1 in beta-amyloid clearance and reducing hyperphosphorylation tau in Alzheimer's disease (AD). There is a need to investigate the IGF-1 response to exercise in AD patients due to well-known potential effects of exercise on IGF-1. The aim of this study was to examine circulating IGF-1 levels in AD patients and older adults without dementia after acute exercise and to verify the associations among cardiorespiratory fitness, cognition and IGF-1 levels.

METHOD

Seventy-four older adults (40 older adults without dementia and 34 AD patients) participated in this study. The outcomes included IGF-1 plasma levels and performance in the submaximal exercise stress test. Secondary outcomes included cognitive functions, depressive symptoms, level of physical activity, insulin-resistance, and cholesterol. All participants performed the incremental test on a treadmill and IGF-1 was collected before and after the exercise.

RESULTS

A tendency to the difference of baseline IGF-1 plasma levels between the groups was found. After the acute exercise AD patients also presented higher levels of circulating IGF-1 compared to the Older adults without dementia. Correlations among cardiorespiratory fitness and cognitive functions were found.

CONCLUSION

The findings suggest that AD patients and older adults respond differently to acute exercise in terms of circulating IGF-1 levels. This response seems to indicate either an IGF-1 resistance or a compensatory exercise-induced to lower IGF-1 levels in AD patients. Cardiorespiratory fitness is associated with global cognition, executive function, attention and information processing speed.

One-Week High-Intensity Interval Training Increases Hippocampal Plasticity and Mitochondrial Content without Changes in Redox State

Evidence suggests that physical exercise has effects on neuronal plasticity as well as overall brain health. This effect has been linked to exercise capacity in modulating the antioxidant status, when the oxidative stress is usually linked to the neuronal damage. Although high-intensity interval training (HIIT) is the training-trend worldwide, its effect on brain function is still unclear. Thus, we aimed to assess the neuroplasticity, mitochondrial, and redox status after one-week HIIT training. Male (C57Bl/6) mice were assigned to non-trained or HIIT groups. The HIIT protocol consisted of three days with short bouts at 130% of maximum speed (Vmax), intercalated with moderate-intensity continuous exercise sessions of 30 min at 60% Vmax. The mass spectrometry analyses showed that one-week of HIIT increased minichromosome maintenance complex component 2 (MCM2), brain derived neutrophic factor (BDNF), doublecortin (DCX) and voltage-dependent anion-selective channel protein 2 (VDAC), and decreased mitochondrial superoxide dismutase 2 (SOD 2) in the hippocampus. In addition, one-week of HIIT promoted no changes in H₂O₂ production and carbonylated protein concentration in the hippocampus as well as in superoxide anion production in the dentate gyrus. In conclusion, our one-week HIIT protocol increased neuroplasticity and mitochondrial content regardless of changes in redox status, adding new insights into the neuronal modulation induced by new training models.

The Combination Effects of Resveratrol and Swimming HIIT Exercise on Novel Object Recognition and Open-field Tasks in Aged Rats

INTRODUCTION

Resveratrol, a natural polyphenol abundant in grapes and red wine, has been reported to exert numerous beneficial health effects in the body. High-Intensity Interval Exercise (HIIT) is a form of interval training that provides improved athletic capacity and has a protective effect on health. The purpose of this study was to investigate the interactive effects of swimming HIIT and Resveratrol supplementation on behavioral function in Novel object recognition and open-field tests in aged rats.

METHODS

A total of 45 aged male Wistar rats with an age of 20 months were randomly assigned into five groups of control (C), swimming HIIT (SW-HIIT), swimming HIIT with Resveratrol supplementation (SW-HIIT-R), Resveratrol supplementation (R), and solvent of Resveratrol supplementation (SR). There was also another group that included young animals (2-month-old) and was used to compare with older animals. Swimming HIIT and Resveratrol supplementation groups performed the exercise and received Resveratrol (10 mg/kg/day, gavage) for six weeks. Novel object recognition and open-field tests were used for evaluating the behavioral functions in animals.

RESULTS

The results showed that HIIT and Resveratrol significantly improved recognition memory compared to old animals. Moreover, it seems that HIIT and Resveratrol partly could modulate anxiety-like behaviors compared to old animals in the open-field test.

Effects of low- and high-intensity physical exercise on physical and cognitive function in older persons with dementia: a randomized controlled trial

BACKGROUND

Potential moderators such as exercise intensity or apolipoprotein-E4 (ApoE4) carriership may determine the magnitude of exercise effects on physical and cognitive functions in patients with dementia (PwD). We determined the effects of a 24-week aerobic and strength training program with a low- and high-intensity phase on physical and cognitive function.

METHODS

In an assessor-blinded randomized trial, 91 PwD (all-cause dementia, recruited from daycare and residential care facilities, age 82.3 ± 7.0 years, 59 women, Mini-Mental State Examination 20.2 ± 4.4) were allocated to the exercise or control group. In the exercise group, PwD participated in a walking and lower limb strength training program with 12 weeks low- and 12 weeks high-intensity training offered three times/week. Attention-matched control participants performed flexibility exercises and recreational activities. We assessed adherence, compliance, and exercise intensity for each session. We assessed physical (endurance, gait speed, mobility, balance, leg strength) and cognitive (verbal memory, visual memory, executive function, inhibitory control, psychomotor speed) functions with performance-based tests at baseline and after 6, 12, 18, 24, and 36 weeks (follow-up). ApoE4 carriership was determined post-intervention.

RESULTS

Sixty-nine PwD were analyzed. Their mean attendance was ~ 60% during the study period. There were no significant effects of the exercise vs. control intervention on endurance, mobility, balance, and leg strength in favor of the exercise group (Cohen's d = 0.13-0.18). Gait speed significantly improved with ~ 0.05 m/s after the high-intensity phase for exercise participants (Cohen's d = 0.41) but declined at follow-up. There were no significant effects of the exercise vs. control intervention on any of the cognitive measures (Cohen's d ~ - 0.04). ApoE4 carriership did not significantly moderate exercise effects on physical or cognitive function.

CONCLUSIONS

Exercise was superior to control activities for gait speed in our sample of PwD. However, the training effect provided no protection for mobility loss after detraining (follow-up). There were no beneficial effects of the exercise vs. control group on cognitive function. Exercise intensity moderated the effects of exercise on gait speed. ApoE4 carriership moderated the effect of exercise on global cognition only (trend level).

TRIAL REGISTRATION

Netherlands Trial Register, NTR5035. Registered on 2 March 2015.

Protective Effects of Spirulina platensis, Voluntary Exercise and Environmental Interventions Against Adolescent Stress-Induced Anxiety and Depressive-Like Symptoms, Oxidative Stress and Alterations of BDNF and 5HT-3 Receptors of the Prefrontal Cortex in Female Rats

BACKGROUND AND PURPOSE

Ample evidence indicates that chronic adolescence stress is associated with an increased risk of developing neuropsychiatric disorders in adulthood. Given the importance of the effective therapeutic ways to overcome adolescent stress-related deficits, the present study investigated the effects of Spirulina platensis (SP), environmental enrichment (EE), and voluntary exercise (EX) and their combination on anxiety or depression-like behaviors, oxidative stress, and alterations of BDNF and 5HT-3 receptors in the prefrontal cortex (PFC) induced by adolescent stress in adult female rats.

METHODS

During the adolescent period (PNDs30-40), rats were subjected to restraint stress. Then, the animals were subjected to SP treatment (200 mg/kg/day), EX, EE, and the combined treatments (SP+EX, and SP+EE) for 15 days between PNDs41-55. Subsequently, anxiety or depression-like behaviors, BDNF levels, oxidative stress markers and mRNA expression of BDNF and 5HT₃ in the PFC were assessed.

RESULTS

Stressed rats demonstrated enhanced anxiety levels and depression-like behaviors in adulthood. Regarding the oxidative stress markers, stressed rats exhibited significantly higher levels of malondialdehyde, a lipid peroxidation product, higher activities of antioxidant enzymes (glutathione peroxidase and superoxide dismutase) and significantly lower total antioxidant reactivity capacity in the PFC. Additionally, adolescent stress significantly increased 5HT3 receptor mRNA expression and decreased BDNF content and its mRNA expression in the PFC. Treatments with SP, EX, EE, and the combined interventions alleviated these deficits.

CONCLUSION

Our findings indicate that appropriate interventions during the adolescent period can protect against adolescent stress-induced behavioral, and biochemical defects and oxidative stress damage in adulthood.

Effects of preconditioning exercise on nitric oxide and antioxidants in hippocampus of epileptic seizure

The mechanism of epileptic seizure has not been identified clearly. Exercise can play a role of antioxidants against oxidative stress. In the present study, the neuroprotective effects of preconditioning exercise on epileptic seizure were investigated with focusing on antioxidants activity in the hippocampus. Rats were allocated to the following groups: saline control group, kainic acid control group, and previous exercise and kainic acid group. Rats in the previous exercise and kainic acid group were subjected to treadmill exercise 5 days a week for 4 weeks. After 48 hr of exercise period, rats in the kainic acid control group and previous exercise and kainic acid group were injected with kainic acid. The number of neuronal nitric oxide synthase-positive cells and the level of nitrite in hippocampus were increased and the expressions of superoxide dismutase-1, superoxide dismutase-2, and catalase in hippocampus were reduced in kainic acid control group compared with saline control group. By contrast, in the previous exercise and kainic acid group, the number of neuronal nitric oxide synthase-positive cells and the level of nitrite were decreased and the expressions of superoxide dismutase-1, superoxide dismutase-2, and catalase were increased compared with the kainic acid control group. Preconditioning exercise may have neuroprotective effects against oxidative stress via increased antioxidant activity in the hippocampus of epileptic seizure.

Akt dependent adult hippocampal neurogenesis regulates the behavioral improvement of treadmill running to mice model of post-traumatic stress disorder

Physical exercise is well-established paradigm for improving adult neurogenesis and brain functions. As considered as an alternative therapeutic strategy, treadmill running could reduce cognitive impairment and psychiatric abnormalities associating post-traumatic stress disorder (PTSD), which might associate with the promote effects to adult neurogenesis. In current study, we aimed to address how treadmill exercise benefit adult hippocampal neurogenesis in PTSD model and the underlying molecular mechanism related with Akt signaling. PTSD was induced by exposure to aggressor and treatments were conducted with different intensity of compulsory treadmill running. We observed treadmill running improved hippocampal neurogenesis including proliferation and neural differentiation of neural stem cells (NSCs). Moreover, behavioral tests showed treadmill could attenuate the cognitive deficit and depressive/anxiety like behaviors in correlating with PTSD model. Moreover, treadmill running recovered the Akt activity in hippocampus. Interrupting treadmill running administrated mice with Akt inhibitor GSK690693 resulted in the blocked the effects of treadmill running to hippocampal neurogenesis and behavioral improvement in PTSD mice model. In conclusion, treadmill running could mediate behavioral functions and improve hippocampal neurogenesis in PTSD model by regulating Akt signaling.

Does brain-derived neurotrophic factor mediate the effects of exercise on memory?

Objective: Brain-derived neurotrophic factor (BDNF) has been hypothesized as a potential mechanism through which exercise may subserve memory function. The present review specifically evaluates this hypothesis.Methods: Studies were identified using electronic databases, including PubMed, PsychInfo, Sports Discus and Google Scholar.Results: In total, 52 articles met the study criteria, and among these, 36 were conducted in an animal model and 16 among humans. Among the animal experiments, 100% of them demonstrated that chronic exercise improved memory function; 97% demonstrated an exercise-induced increase in BDNF; and among the eight evaluating BDNF as a mediator, 100% provided evidence that BDNF mediated the relationship between exercise and memory. The findings in the human studies were mixed. Among the human studies, 44% demonstrated that varying exercise protocols improved memory and increased BDNF levels, and among the studies evaluating BDNF as a mediator, 40% provided evidence that BDNF mediated the relationship between exercise and memory.Conclusion: In animal models, chronic exercise training robustly increases BDNF and improves memory performance, with reasonable evidence to also suggest that BDNF may mediate the exercise-memory interaction. These interrelationships, however, are less clear among humans. Future research among humans, in particular, is needed to evaluate the extent to which BDNF may mediate the relationship between exercise and memory.

Efficacy of a low-dose melatonin pretreatment in protecting against the neurobehavioral consequences of chronic hypoperfusion in middle-aged female rats

Mild cognitive impairment (MCI) is characterized by a reduction in cerebral blood flow. Permanent ligation of the common carotid arteries (2VO) in the rat mimics the chronic decrease in CBF that characterizes aMCI. The current study determined if melatonin (a pineal hormone with neuroprotective properties) can attenuate the neurobehavioral consequences of 2VO using middle-aged female rats. Two weeks following 2VO or sham surgery, rats were tested on various learning and memory tasks. 2VO resulted in hyperlocomotion on the open field. Melatonin attenuated this 2VO-induced hyperactivity. 2VO impaired visual memory however this was not attenuated by melatonin administration. Neither 2VO nor melatonin affected spatial memory performance on the MWM or spatial recognition task. Y-maze testing revealed 2VO rats exhibited a lower spontaneous alternation pattern and performed a greater number of alternate arm returns compared to 2VO rats treated with melatonin. 2VO resulted in a significant loss of CA1 hippocampal neurons which was attenuated with melatonin treatment. Chronic melatonin was found to attenuate the neuronal consequences of chronic cerebral hypoperfusion but only conferred partial behavioral protection in middle-aged female rats. Our results demonstrate that inclusion of older rodents is important in neuroprotection studies as neuroprotective agents may act differently in an aged brain.

Exercise for Brain Health: An Investigation into the Underlying Mechanisms Guided by Dose

There is a strong link between the practice of regular physical exercise and maintenance of cognitive brain health. Animal and human studies have shown that exercise exerts positive effects on cognition through a variety of mechanisms, such as changes in brain volume and connectivity, cerebral perfusion, synaptic plasticity, neurogenesis, and regulation of trophic factors. However, much of this data has been conducted in young humans and animals, raising questions regarding the generalizability of these findings to aging adults. Furthermore, it is not clear at which doses these effects might take place, and if effects would differ with varying exercise modes (such as aerobic, resistance training, combinations, or other). The purpose of this review is to summarize the evidence on the effects of exercise interventions on various mechanisms believed to support cognitive improvements: cerebral perfusion, synaptic neuroplasticity, brain volume and connectivity, neurogenesis, and regulation of trophic factors. We synthesized the findings according to exposure to exercise (short- [1 day-16 weeks], medium- [24-40 weeks], and long-term exercise [52 weeks and beyond]) and have limited our discussion of dose effects to studies in aging adults and aged animals (when human data was not available).

Long-term environmental modifications affect BDNF concentrations in rat hippocampus, but not in serum

The role of mBDNF on the beneficial effects of cognitive stimulation on the brain remains controversial, as well as the potential of peripheral mBDNF as a biomarker of environmental effects on its central status. We investigated the effect of different environmental conditions on recognition memory, proBDNF, mBDNF and synaptophysin levels in the hippocampus, and on mBDNF levels in blood. Male Wistar rats (6 and 17 months-old) were assigned to cognitively enriched (EE), standard (SE) and impoverished (IE) environmental conditions for twelve weeks. Novel object recognition was performed at week 10. When the animals were 9 and 20-months old, hippocampus was collected for mBDNF, proBDNF and synaptophysin analysis; serum was analyzed for mBDNF levels. The cognitively EE improved recognition memory, resulted in a trend to increased hippocampal mBDNF and augmented synaptophysin levels. Accordingly, hippocampal mBDNF, proBDNF and synaptophysin were significantly higher in EE than IE animals. Hippocampal mBDNF was positively correlated to proBDNF, cellular and behavioral plasticity markers. No effect of age was seen on the studied variables. Moreover, no significant effects of EE or IE on serum mBDNF were observed. Serum mBDNF also failed to correlate with hippocampal mBDNF, proBDNF and with the cellular and behavioral plasticity markers. These findings indicate that mBDNF is involved in neuronal and behavioral plasticity mechanisms induced by cognitively enriched environments, and that peripheral mBDNF may not always be a reliable biomarker of the effects of environmental settings on central mBDNF and plasticity, which is of special interest from a translational research perspective.

How does physical activity and different models of exercise training affect oxidative parameters and memory?

The present study investigated the chronic effects of different physical exercise and physical activity models on cognitive function, cholinergic activity, and oxidative stress markers in the cerebral cortex and hippocampus. Eighty 60-day old C57BL/6 mice were divided into the following five groups: Sedentary (SED), moderate-intensity continuous training (MICT), high-intensity interval training (HIIT), resistance training (RT), and physical activity (RW, for "running wheel"). Cognitive function (recognition and spatial memory), oxidative stress parameters, and acetylcholinesterase (AChE) activity in the cerebral cortex and hippocampus were evaluated. MICT mice exhibited enhanced recognition memory compared to SED mice (p = .046) and other exercised groups (HIIT: p < .001; RW: p = .003; RT: p < .001). The RT group showed better spatial memory compared to the SED (p = .004), MICT (p = .019), and RW (p = .003) groups. RW, MICT, HIIT, and RT training models reduced nitrites in the hippocampus compared to the SED group. RT led to a significant increase in both lipid peroxidation (p = .01) and reactive oxygen species (ROS) (p < .001) levels compared to the SED group in the hippocampus. MICT promoted an increase in catalase (CAT) activity (p = .002), while superoxide dismutase (SOD) activity was diminished by RT compared to MICT and HIIT (p = .008). In the cerebral cortex, RT increased ROS levels, but exhibited the lowest lipid peroxidation level among the groups (p < .001). The RW group showed an activity-induced increase in lipid peroxidation level compared to the SED group, and the highest level of CAT activity among all groups (p < .001). AChE activity was higher in the RT group compared to the SED, MICT, and RW groups (p = .039) in the cerebral cortex. In summary, nitrite levels in the hippocampus were decreased in all intervention groups regardless of activity or exercise model. Likewise, MICT improved recognition memory besides increasing CAT activity. We conclude that the MICT and RT protocols seem to act as oxidative stress regulators and non-pharmacological strategies to improve cognitive function.

Physical exercise, IGF-1 and cognition A systematic review of experimental studies in the elderly

One of hypothetical mechanisms related to cognition is exercise-induced IGF-1.