Moderate Treadmill Exercise Protects Synaptic Plasticity of the Dentate Gyrus and Related Signaling Cascade in a Rat Model of Alzheimer's Disease

Efficacy of exercise rehabilitation for managing patients with Alzheimer's disease

Alzheimer's disease (AD) is a progressive and degenerative neurological disease characterized by the deterioration of cognitive functions. While a definitive cure and optimal medication to impede disease progression are currently unavailable, a plethora of studies have highlighted the potential advantages of exercise rehabilitation for managing this condition. Those studies show that exercise rehabilitation can enhance cognitive function and improve the quality of life for individuals affected by AD. Therefore, exercise rehabilitation has been regarded as one of the most important strategies for managing patients with AD. Herein, we provide a comprehensive analysis of the currently available findings on exercise rehabilitation in patients with AD, with a focus on the exercise types which have shown efficacy when implemented alone or combined with other treatment methods, as well as the potential mechanisms underlying these positive effects. Specifically, we explain how exercise may improve the brain microenvironment and neuronal plasticity. In conclusion, exercise is a cost-effective intervention to enhance cognitive performance and improve quality of life in patients with mild to moderate cognitive dysfunction. Therefore, it can potentially become both a physical activity and a tailored intervention. This review may aid the development of more effective and individualized treatment strategies to address the challenges imposed by this debilitating disease, especially in low- and middle-income countries.

Exercise epigenetics is fueled by cell bioenergetics: Supporting role on brain plasticity and cognition

Exercise has the unique aptitude to benefit overall health of body and brain. Evidence indicates that the effects of exercise can be saved in the epigenome for considerable time to elevate the threshold for various diseases. The action of exercise on epigenetic regulation seems central to building an "epigenetic memory" to influence long-term brain function and behavior. As an intrinsic bioenergetic process, exercise engages the function of the mitochondria and redox pathways to impinge upon molecular mechanisms that regulate synaptic plasticity and learning and memory. We discuss how the action of exercise uses mechanisms of bioenergetics to support a "epigenetic memory" with long-term implications for neural and behavioral plasticity. This information is crucial for directing the power of exercise to reduce the burden of neurological and psychiatric disorders.

Moderate aerobic training enhances the effectiveness of insulin therapy through hypothalamic IGF1 signaling in rat model of Alzheimer's disease

Alzheimer's disease (AD) is a neurological condition that is connected with a decline in a person's memory as well as their cognitive ability. One of the key topics of AD research has been the exploration of metabolic causes. We investigated the effects of treadmill exercise and intranasal insulin on learning and memory impairment and the expression of IGF1, BDNF, and GLUT4 in hypothalamus. The animals were put into 9 groups at random. In this study, we examined the impact of insulin on spatial memory in male Wistar rats and analyzed the effects of a 4-week pretreatment of moderate treadmill exercise and insulin on the mechanisms of improved hypothalamic glucose metabolism through changes in gene and protein expression of IGF1, BDNF, and GLUT4. We discovered that rat given Aβ25-35 had impaired spatial learning and memory, which was accompanied by higher levels of Aβ plaque burden in the hippocampus and lower levels of IGF1, BDNF, and GLUT4 mRNA and protein expression in the hypothalamus. Additionally, the administration of exercise training and intranasal insulin results in the enhancement of spatial learning and memory impairments, the reduction of plaque burden in the hippocampus, and the enhancement of the expression of IGF1, BDNF, and GLUT4 in the hypothalamus of rats that were treated with Aβ25-35. Our results show that the improvement of learning and spatial memory due to the improvement of metabolism and upregulation of the IGF1, BDNF, and GLUT4 pathways can be affected by pretreatment exercise and intranasal insulin.

Aerobic exercise combined with chlorogenic acid exerts neuroprotective effects and reverses cognitive decline in Alzheimer's disease model mice (APP/PS1) via the SIRT1/ /PGC-1α/PPARγ signaling pathway

Alzheimer's disease (AD) is a prevalent neurodegenerative disease account for 60-80% of the total number of people with dementia, but its treatment and prevention strategies are still in a long process of exploration. It has been reported that a healthy lifestyle may be an effective non-pharmacological intervention for the prevention and treatment of AD, including increased physical activity and the consumption of polyphenol-rich foods. This study, therefore, investigated the effects of 8 weeks of moderate-intensity aerobic exercise (EX), administration of chlorogenic acid administration (GCA), and a combination of both (EX+GCA) on β-amyloid (Aβ) deposition, inflammatory factors, oxidative stress markers, neuronal damage, and cognitive performance in the brains of AD model mice (APP/PS1) and which signaling pathways may be responsible for these effects. The study used Western blot to detect the expression of signaling pathway-related proteins, enzyme-linked immunosorbent assay to detect the expression of inflammatory factors, hematoxylin-eosin staining to detect hippocampal neuronal morphology, immunohistochemistry to detect changes in Aβ deposition in the hippocampus, an oxidative stress marker kit to detect oxidative stress status and the Morris water maze to detect changes in cognitive performance. This study showed that an 8-week intervention (EX/GCA/EX+GCA) activating the SIRT1/PGC-1α signaling pathway improved oxidative stress, neuroinflammation, Aβ deposition, and cognitive performance in mice. However, there was no obvious difference between the EX and GCA groups. In contrast, the combined EX+GCA intervention was significantly better than phase EX or GCA. Our study suggests that although relief of Aβ deposition, neuroinflammation, oxidative stress, neuronal damage, and cognitive decline could also be achieved with EX or GCA, the combined EX+GCA intervention showed better results. These relief effects on AD-related conditions may be obtained by mediating the activation of the SIRT1/PGC-1α signaling pathway. This study is the first to explore the improvement of AD-related conditions with a combined lifestyle of EX+GCA. This healthy lifestyle could be a candidate option for the treatment of AD.

Effect of exercise on cognitive function and synaptic plasticity in Alzheimer's disease models: A systematic review and meta-analysis

Introduction

Cognitive decline is a central manifestation of Alzheimer's disease (AD), and its process is inseparable from changes in synaptic plasticity. The aim of this review was to summarize and evaluate the effectiveness of exercise on cognitive function and synaptic plasticity in AD animal models.

Materials and methods

Eligible studies were searched from PubMed, MEDLINE, EMBASE, Web of Science, and Cochrane Library from April to May 2022. The risk of bias was evaluated by Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE). The Morris water maze (MWM) test and synaptic plasticity were considered outcome measures. Data were analyzed using random-effects meta-analyses using the software Stata. Heterogeneity was examined by using I2 test. Sensitivity analysis and publication bias were also assessed.

Results

A total of 20 randomized controlled studies were eligible for study inclusion. Compared with controls, exercise decreased escape latency (SMD = -0.86, 95% CI: -1.21 to -0.50, P < 0.001), increased platform crossover numbers (SMD = 1.34, 95% CI: 0.57-2.11, P = 0.001) and time in the target quadrant (SMD = 1.65, 95% CI: 0.95-2.36, P < 0.001) and the expression of PSD95 (SMD = 0.73, 95% CI: 0.25-1.21, P = 0.003) in AD animals. The results of the subgroup analysis showed that exercise before AD had a greater effect on escape latency (SMD = -0.88, 95% CI: -1.25 to -0.52, P < 0.001), platform crossover numbers (SMD = 1.71, 95% CI: 1.23-2.18, P < 0.001), time in the target quadrant (SMD = 2.03, 95% CI: 1.19-2.87, P < 0.001) and the expression of PSD95 (SMD = 0.94, 95% CI: 0.19-1.69, P = 0.014) than exercise after AD. The results of the subgroup analysis also showed that treadmill running might be an appropriate exercise type.

Conclusion

Our findings suggested that exercise had a potential effect on improving cognitive function and synaptic plasticity. It can play a better neuroprotective role before AD.

Systematic review registration

PROSPERO, identifier: CRD42022328438.

Overview on brain function enhancement of Internet addicts through exercise intervention: Based on reward-execution-decision cycle

Internet addiction (IA) has become an impulse control disorder included in the category of psychiatric disorders. The IA trend significantly increased after the outbreak of the new crown epidemic. IA damages some brain functions in humans. Emerging evidence suggests that exercise exerts beneficial effects on the brain function and cognitive level damaged by IA. This work reviews the neurobiological mechanisms of IA and describes the brain function impairment by IA from three systems: reward, execution, and decision-making. Furthermore, we sort out the research related to exercise intervention on IA and its effect on improving brain function. The internal and external factors that produce IA must be considered when summarizing movement interventions from a behavioral perspective. We can design exercise prescriptions based on exercise interests and achieve the goal of quitting IA. This work explores the possible mechanisms of exercise to improve IA through systematic analysis. Furthermore, this work provides research directions for the future targeted design of exercise prescriptions.

Treadmill exercise training improves the high-fat diet-induced behavioral changes in the male rats

The purpose of this study was to investigate the effects of treadmill exercise training on obesity-induced behavioral changes in high-fat diet (HFD)-induced male rats. In this study, 40 male Sprague-Dawley rats were divided into 4 groups after they were weaned: Control (C), Exercise (E), Obese (O) and Obese + Exercise (O + E). For the obesity model % 60 high-fat diet were applied. After obesity was induced, rats were either moderate aerobic exercise (treadmill running) trained or left untrained. Different tasks to assess spatial learning and memory (Morris water maze test (MWMT)), depressive-like behavior (forced swimming test(FST), tail suspension test (TST) and anxiety-like behavior (light-dark test (LDT) and open field test (OFT)) were conducted. Exercise caused a significant reduction in duration of immobility in the O group in FST and the decrease in immobility in the O + E rats in TST. The O + E rats demonstrated a significant increase in the time spent in the light box as compared to the O group in the LDT. The O + E rats did not show any behavioral alterations as compared to all the other groups in the OFT. In the O + E group, there was a significant increase in the time spent in the target quadrant compared to the O group in the MWMT. Our results support that treadmill exercise could improve cognitive, depressive-like, anxiety-like behavioral changes in the HFD-induced obese rats.

Physical Exercise, a Potential Non-Pharmacological Intervention for Attenuating Neuroinflammation and Cognitive Decline in Alzheimer's Disease Patients

This narrative review summarises the evidence for considering physical exercise (PE) as a non-pharmacological intervention for delaying cognitive decline in patients with Alzheimer’s disease (AD) not only by improving cardiovascular fitness but also by attenuating neuroinflammation. Ageing is the most important risk factor for AD. A hallmark of the ageing process is a systemic low-grade chronic inflammation that also contributes to neuroinflammation. Neuroinflammation is associated with AD, Parkinson’s disease, late-onset epilepsy, amyotrophic lateral sclerosis and anxiety disorders. Pharmacological treatment of AD is currently limited to mitigating the symptoms and attenuating progression of the disease. AD animal model studies and human studies on patients with a clinical diagnosis of different stages of AD have concluded that PE attenuates cognitive decline not only by improving cardiovascular fitness but possibly also by attenuating neuroinflammation. Therefore, low-grade chronic inflammation and neuroinflammation should be considered potential modifiable risk factors for AD that can be attenuated by PE. This opens the possibility for personalised attenuation of neuroinflammation that could also have important health benefits for patients with other inflammation associated brain disorders (i.e., Parkinson’s disease, late-onset epilepsy, amyotrophic lateral sclerosis and anxiety disorders). In summary, life-long, regular, structured PE should be considered as a supplemental intervention for attenuating the progression of AD in human. Further studies in human are necessary to develop optimal, personalised protocols, adapted to the progression of AD and the individual’s mental and physical limitations, to take full advantage of the beneficial effects of PE that include improved cardiovascular fitness, attenuated systemic inflammation and neuroinflammation, stimulated brain Aβ peptides brain catabolism and brain clearance.

The effect of 4-Week rehabilitation by aerobic exercise on hippocampus BDNF and TGF-β1 gene expressions inAβ 1-42-induced rat model of Alzheimer's disease

Alzheimer's disease (AD) is a type of brain dysfunction featuring a gradual loss in memory. This study aimed to determine the effect of 4 weeks of aerobic rehabilitation exercise (RhExe) on the genes expression of BDNF and TGF-β1 in the hippocampus tissue of rats with the AD induced by injection of amyloid-beta (Aβ_1-42). Twenty-one male Wistar rats were randomly divided into 3 groups: Aβ injection (n = 7), Aβ + exercise (n = 7) and control (n = 7). AD was induced by a single dose of Aβ injection into the hippocampus of rats. Three days after surgery, the Aβ + exercise group experienced four weeks of the RhExe (5 days/week). Forty-eight hours after the last training session, the animals underwent the Morris water maze test. The animals were sacrificed 24 h after the test, and hippocampal tissue was split. The mRNA expression of BDNF, TGF-β1, and TGF-β1 II receptors was measured. The TGF-β1 and TGF-β1 II receptor genes expression of Aβ + exercise group were significantly higher than the Aβ injection group (P ≤ 0.001). BDNF gene expression in the hippocampus of the Aβ + exercise group was significantly higher than the Aβ injection group (P ≤ 0.001). Spatial memory was significantly higher in the Aβ + exercise group than in the Aβ injection group (p ≤ 0.01). It seems that aerobic exercise can counteract the harmful effects of Aβ through the BDNF and TGF-β1molecular signaling pathways.

Impact of interval training with probiotic (L. plantarum / Bifidobacterium bifidum) on passive avoidance test, ChAT and BDNF in the hippocampus of rats with Alzheimer's disease

It has been suggested that gut microbiota dysbiosis can lead to Alzheimer's disease (AD), inducing the production of many AD-related pre-inflammatory cytokines. On the other hand, daily probiotic administration and regular exercise training are assumed to improve clinical AD-related symptoms. To take this line of research further, this study was aimed at investigating the impact of moderate-intensity interval training (MIIT) with a combined administration of Lactobacillus plantarum and Bifidobacterium bifidum (probiotic, BROB) on the passive avoidance test (Shuttle Box), choline acetyltransferase (ChAT) and the brain derived neurotrophic factor (BDNF) in the hippocampus of a rat model of AD. Forty male Wistar rats (280 ± 20 g) were divided into five groups (n = 8 in each) of control, amyloid beta peptide (Aβ), Aβ + MIIT (AD rats undergoing MIIT), Aβ + PROB (AD rats fed Lactobacillus plantarum and Bifidobacterium bifidum), and Aβ + MIIT + PROB (AD rats receiving both treatments). AD was induced by the intra-cerebroventricular injection of Aβ1-42 peptide. MIIT was performed on rodent treadmill for 8 weeks (5 days per week). The probiotic was also fed daily to the related groups for 8 weeks. BDNF and ChAT in the hippocampus were measured by real time PCR (RT-PCR) and immunohistochemistry (IHC), respectively. Cresyl violet staining of brain tissue was performed to evaluate the dead cells. Results of tissue staining showed that the induction of the Alzheimer's led to the destruction of hippocampal cells and induced neurodegeneration (p = 0.001). Results of the shuttle box test showed that short-term memory was improved in the Aβ + MIIT + PROB group compared to the Aβ group, while death cells (dark cells) were decreased in all the other three groups (MIIT, BROB, and Aβ + MIIT + PROB). Levels of ChAT as well as the BDNF mRNA in the Aβ + MIIT + PROB group showed a significant increase compared to the Aβ group. In conclusion, it seems that the use of the combined administration of Lactobacillus plantarum and Bifidobacterium bifidum with interval aerobic exercise can have neuroprotective effects on AD.

An 8-Week Administration of Bifidobacterium bifidum and Lactobacillus plantarum Combined with Exercise Training Alleviates Neurotoxicity of Aβ and Spatial Learning via Acetylcholine in Alzheimer Rat Model

This study aimed to determine the effects of 8 weeks of an administration of Bifidobacterium bifidum and Lactobacillus plantarum combined with exercise training on neurotoxicity of Aβ, spatial learning, acetylcholine (ACH), and vascular endothelial growth factor (VEGF) in Alzheimer rats. Twenty-five Wistar rats were randomly divided into 5 groups (n = 5 in each): (1) healthy control (control), (2) Alzheimer disease (AD), (3) AD with treadmill exercise (AD + Exe), (4) AD with probiotic (combined administration of Bifidobacterium bifidum and Lactobacillus plantarum) treatment (AD + Pro), and (5) AD with treadmill exercise and probiotic treatment (AD + Exe + Pro). AD was induced by intra-cerebroventricular injection of Aβ1-42 peptide. Then, the training groups exercised on treadmill for 8 weeks, 5 days per weeks. The rats were treated daily with probiotic supplements via gavage for 8 weeks. The Morris water maze (MWM) test was administered to measure spatial learning. Then, the animals were sacrificed and Vegf and ACH were analyzed using the qPCR and immunohistochemistry (IHC) methods, respectively. Results showed that the β-amyloid plaques were significantly increased in the brains of the AD group compared with the control group (p < 0.001). The combined use of probiotics and exercise training significantly increased the time spent in the target quadrant after removing the platform, compared with the AD group in the Morris water maze test (p < 0.001). Crystal violet analysis showed that sole (p < 0.01) and combined exercise training and probiotic supplementation (p < 0.001) significantly reduced the number of dead cells in the brains of rats compared with the AD group. AD significantly decreased Vegf mRNA and ACH in the CA1 area of the hippocampus (p < 0.001). However, mono and combined therapy (exercise and probiotics) significantly increased ACH in the rats' brain compared with the AD group. Overall, 8 weeks of an administration of Bifidobacterium bifidum and Lactobacillus plantarum combined with exercise training can improve spatial learning impairment in the AD rats. Exercise and probiotics seem to offer potential benefits to AD patients by upregulating ACH.

Physical Exercise and Alzheimer's Disease: Effects on Pathophysiological Molecular Pathways of the Disease

Alzheimer’s disease (AD), the most common form of neurodegenerative dementia in adults worldwide, is a multifactorial and heterogeneous disorder characterized by the interaction of genetic and epigenetic factors and the dysregulation of numerous intracellular signaling and cellular/molecular pathways. The introduction of the systems biology framework is revolutionizing the study of complex diseases by allowing the identification and integration of cellular/molecular pathways and networks of interaction. Here, we reviewed the relationship between physical activity and the next pathophysiological processes involved in the risk of developing AD, based on some crucial molecular pathways and biological process dysregulated in AD: (1) Immune system and inflammation; (2) Endothelial function and cerebrovascular insufficiency; (3) Apoptosis and cell death; (4) Intercellular communication; (5) Metabolism, oxidative stress and neurotoxicity; (6) DNA damage and repair; (7) Cytoskeleton and membrane proteins; (8) Synaptic plasticity. Moreover, we highlighted the increasingly relevant role played by advanced neuroimaging technologies, including structural/functional magnetic resonance imaging, diffusion tensor imaging, and arterial spin labelling, in exploring the link between AD and physical exercise. Regular physical exercise seems to have a protective effect against AD by inhibiting different pathophysiological molecular pathways implicated in AD.

Physical exercise promotes brain remodeling by regulating epigenetics, neuroplasticity and neurotrophins

Exercise has been shown to have beneficial effects on brain functions in humans and animals. Exercise can improve memory and learning in age-related neurodegenerative diseases. In animal models, physical exercise regulates epigenetics, promotes synaptic plasticity and hippocampal neurogenesis, regulates the expression levels of neurotrophic factors, and improves cognitive function. Therefore, exercise is very important for brain rehabilitation and remodeling. The purpose of this review is to explore the mechanisms by which exercise exerts positive effects on brain function. This knowledge implies that physical exercise can be used as a non-drug therapy for neurological diseases.

Moderate treadmill exercise improves spatial learning and memory deficits possibly via changing PDE-5, IL-1 β and pCREB expression

Alzheimer's is a progressive disorder of the nervous system. Prior studies suggested that physical activity contributes to the improvement of cognitive impairment and slows down pathogenesis of AD; however, the exact mechanisms for this have not been fully understood. Therefore, in this study, we examined the effect of aerobic training before and after induction of Alzheimer's on spatial learning and memory, expression of interleukin-1 beta (IL-1β), cAMP-responsive element-binding protein (pCREB), and Phosphodiesterase-5 (PDE-5) in the hippocampus of male rats Wistar. Aβ was microinjected into the CA1 area of the hippocampus animals. The moderate treadmill exercise protocols for pre and post induction of Alzheimer's were the same (5 days/week, for 4 weeks with a customized regime). The Morris Water Maze (MWM) method has been to assess spatial learning and memory. The real time-PCR method was used to measure gene expression. Our results showed that intra-hippocampal injection of Aβ1-42 impaired spatial learning and memory which was accompanied by reduced pCREB activity and elevated IL-1β and PDE-5 in the hippocampus of rats. In contrast, moderate treadmill exercise ameliorated the Aβ1-42-induced spatial learning and memory deficit, which was accompanied by restored pCREB activity and decreasing IL-1β and PDE-5 levels. In conclusion, our finding suggests that exercise before and after Alzheimer's induction leads to an increase in pCREB and an alleviation of inflammation which likely involved in ameliorating spatial learning and memory deficits in an animal model of AD.

Effects of exercise on BDNF-TrkB signaling in the paraventricular nucleus and rostral ventrolateral medulla in rats post myocardial infarction

Brain-derived neurotrophic factor (BDNF)-tropomyosin-related kinase B (TrkB) signaling in the paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) is associated with cardiovascular regulation. Exercise increases plasma BDNF and attenuates activation of central pathways in the PVN and RVLM post myocardial infarction (MI). The present study assessed whether MI alters BDNF-TrkB signaling and intracellular factors Ca²⁺/calmodulin-dependent protein kinase II (CaMKII) and Akt in the PVN and RVLM of male Wistar rats with or without exercise or treatment with the TrkB blocker ANA-12. A 4-week period of treadmill exercise training was performed in MI rats. A separate experiment was conducted with 2.5 mg/kg ANA-12 in sedentary MI rats. At 5 weeks post MI, in both the PVN and RVLM, the ratio of full-length TrkB (TrkB.FL) and truncated TrkB (TrkB.T1) was decreased. 0.5 mg/kg ANA-12 did not affect BDNF-TrkB signaling and cardiac function post MI, but 2.5 mg/kg ANA-12 further decreased ejection fraction (EF). Exercise increased mature BDNF (mBDNF) and decreased Akt activity in the PVN, whereas in the RVLM, exercise did not affect mBDNF but lowered p-CaMKIIβ. ANA-12 prevented the exercise-induced increase in mBDNF in the PVN and decrease in p-CaMKIIβ in the RVLM. In conclusion, exercise decreases Akt activity in the PVN and decreases p-CaMKIIβ in the RVLM post MI. BDNF-TrkB signaling only mediates the decrease in p-CaMKIIβ in the RVLM. The exercise-induced decreases in Akt activity in the PVN and p-CaMKIIβ in the RVLM may contribute to the attenuation of the decrease in EF and sympathetic hyperactivity post MI.

Regular Aerobic Exercise-Alleviated Dysregulation of CAMKIIα Carbonylation to Mitigate Parkinsonism via Homeostasis of Apoptosis With Autophagy

This study investigated carbonylation of proteins with oxidative modification profiling in the striatum of aging and Parkinson disease (PD) rats, as well as the long-term effects of regular aerobic exercise on the carbonylation process and the damaging effects of PD vs habitual sedentary behavior. Regular aerobic exercise improved the PD rats' rotational behavior, increased tyrosine hydroxylase expression in both the striatum and substantia nigra pars compacta, and decreased α-synuclein expression significantly. Interestingly, apoptotic nuclei and autophagosomes were increased in the aerobic exercise PD rat striatum. Carbonylated protein Ca2+/calmodulin-dependent protein kinase alpha (CAMKIIα) was present in the middle-aged and aged groups but only in the sedentary, not the exercise, PD rat striatum. Notably, CAMKIIα was characterized by a 4-hydroxynonenal adduct. Regular aerobic exercise upregulated CAMKIIα expression level, activated the CAMK signaling pathway, and promoted the expression of autophagy markers Beclin1 and microtubule-associated proteins 1 A/1B light chain 3II. Aberrant carbonylation of CAMKII initiated age-related changes and might be useful as a potential biomarker of PD. Regular aerobic exercise alleviated protein carbonylation modification of CAMKIIα and regulated the CAMK signaling pathway, thereby affecting and regulating the homeostasis of apoptosis and autophagy in the striatum to alleviate the neurodegenerative process of PD lesions.

The continuum between neurodegeneration, brain plasticity, and movement: a critical appraisal

While the “physiological” aging process is associated with declines in motor and cognitive features, these changes do not significantly impair functions and activities of daily living. Differently, motor and cognitive impairment constitute the most common phenotypic expressions of neurodegeneration. Both manifestations frequently coexist in the same disease, thus making difficult to detect “pure” motor or cognitive conditions. Movement disorders are often characterized by cognitive disturbances, and neurodegenerative dementias often exhibit the occurrence of movement disorders. Such a phenotypic overlap suggests approaching these conditions by highlighting the commonalities of entities traditionally considered distinct. In the present review, we critically reappraised the common clinical and pathophysiological aspects of neurodegeneration in both animal models and patients, looking at motricity as a trait d’union over the spectrum of neurodegeneration and focusing on synaptopathy and oscillopathy as the common pathogenic background. Finally, we discussed the possible role of movement as neuroprotective intervention in neurodegenerative conditions, regardless of the etiology. The identification of commonalities is critical to drive future research and develop novel possible disease-modifying interventions.

New Insights into the Spontaneous Human Alzheimer's Disease-Like Model Octodon degus: Unraveling Amyloid-β Peptide Aggregation and Age-Related Amyloid Pathology

Alzheimer's disease (AD) is the most common cause of dementia worldwide. Despite advances in our understanding of the molecular milieu driving AD pathophysiology, no effective therapy is currently available. Moreover, various clinical trials have continued to fail, suggesting that our approach to AD must be revised. Accordingly, the development and validation of new models are highly desirable. Over the last decade, we have been working with Octodon degus (degu), a Chilean rodent, which spontaneously develops AD-like neuropathology, including increased amyloid-β (Aβ) aggregates, tau hyperphosphorylation, and postsynaptic dysfunction. However, for proper validation of degu as an AD model, the aggregation properties of its Aβ peptide must be analyzed. Thus, in this study, we examined the capacity of the degu Aβ peptide to aggregate in vitro. Then, we analyzed the age-dependent variation in soluble Aβ levels in the hippocampus and cortex of third- to fifth-generation captive-born degu. We also assessed the appearance and spatial distribution of amyloid plaques in O. degus and compared them with the plaques in two AD transgenic mouse models. In agreement with our previous studies, degu Aβ was able to aggregate, forming fibrillar species in vitro. Furthermore, amyloid plaques appeared in the anterior brain structures of O. degus at approximately 32 months of age and in the whole brain at 56 months, along with concomitant increases in Aβ levels and the Aβ42/Aβ40 ratio, indicating that O. degus spontaneously develops AD-like pathology earlier than other spontaneous models. Based on these results, we can confirm that O. degus constitutes a valuable model to improve AD research.

Neurogenesis promoted by the CD200/CD200R signaling pathway following treadmill exercise enhances post-stroke functional recovery in rats

Stroke is a leading cause of long-term disability worldwide; survivors often show sensorimotor and cognitive deficits. Therapeutic exercise is the most common treatment strategy for rehabilitating patients with stroke via augmentation of neurogenesis, angiogenesis, neurotrophic factors expression, and synaptogenesis. Neurogenesis plays important roles in sensorimotor and cognitive functional recovery, and can be promoted by exercise; however, the mechanism underlying this phenomenon remains unclear. In this study, we explored the effects of treadmill exercise on sensorimotor and cognitive functional recovery, as well as the potential molecular mechanisms underlying the promotion of neurogenesis in a rat model of transient middle cerebral artery occlusion (tMCAO). We found that treadmill exercise facilitated sensorimotor and cognitive functional recovery after tMCAO, and that neural stem/progenitor cell proliferation, differentiation, and migration were enhanced in the ipsilateral subventricular and subgranular zones after tMCAO. Meanwhile, the newborn neurons induced by treadmill exercise after tMCAO had the similar function with pre-existing neurons. Treadmill exercise significantly increased CD200 and CD200 receptor (CD200R) levels in the ipsilateral hippocampus and cortex. Further study revealed that treadmill exercise-induced neurogenesis and functional recovery were clearly inhibited, while Il-β and Tnf-α expression were upregulated, following lentivirus (LV)-induced suppression of post-stroke CD200R expression. Consistent with the effect of treadmill exercise, CD200Fc (a CD200R agonist) markedly promoted neurogenesis and functional recovery after stroke. In addition, CD200Fc could further enhance the functional recovery induced by treadmill exercise after stroke. Our results demonstrate the beneficial role of treadmill exercise in promoting neurogenesis and functional recovery via activating the CD200/CD200R signaling pathway and improving the inflammatory environment after stroke. Thus, the CD200/CD200R signaling pathway is a potential therapeutic target for functional recovery after stroke.

Comparative benefits of simvastatin and exercise in a mouse model of vascular cognitive impairment and dementia

Aerobic physical exercise (EX) and controlling cardiovascular risk factors in midlife can improve and protect cognitive function in healthy individuals and are considered to be effective at reducing late-onset dementia incidence. By investigating commonalities between these preventative approaches, we sought to identify possible targets for effective interventions. We compared the efficacy of EX and simvastatin (SV) pharmacotherapy to counteract cognitive deficits induced by a high-cholesterol diet (2%, HCD) in mice overexpressing TGF-β1 (TGF mice), a model of vascular cognitive impairment and dementia. Cognitive deficits were found in hypercholesterolemic mice for object recognition memory, and both SV and EX prevented this decline. EX improved stimulus-evoked cerebral blood flow responses and was as effective as SV in normalizing endothelium-dependent vasodilatory responses in cerebral arteries. The up-regulation of galectin-3-positive microglial cells in white matter (WM) of HCD-fed TGF mice with cognitive deficits was significantly reduced by both SV and EX concurrently with cognitive recovery. Altered hippocampal neurogenesis, gray matter astrogliosis, or microgliosis did not correlate with cognitive deficits or benefits. Overall, results indicate that SV and EX prevented cognitive decline in hypercholesterolemic mice and that they share common sites of action in preventing endothelial cell dysfunction and reducing WM inflammation.-Trigiani, L. J., Royea, J., Tong, X.-K., Hamel, E. Comparative benefits of simvastatin and exercise in a mouse model of vascular cognitive impairment and dementia.

Exercise, spinogenesis and cognitive functions

Exercise training improves mental and cognitive functions by enhancing neurogenesis and neuroprotection. Recent studies suggest the facilitation of spinogenesis across different brain regions including hippocampus and cerebral cortex by physical activity. In this article we will summarize major findings for exercise effects on synaptogenesis and spinogenesis, in order to provide mechanisms for exercise intervention of both psychiatric diseases and neurodegenerative disorders. We will also revisit major findings for molecular mechanism governing exercise-related spinogenesis, and will discuss the screening for novel factors, or exerkines, whose levels are correlated with endurance training and affect neural plasticity. We believe that further studies focusing on the molecular mechanism of exercise-mediate spinogenesis should benefit the optimization of exercise therapy in clinics and the evaluation of treatment efficiency using specific biomarkers.

The Effects of Maternal Atrazine Exposure and Swimming Training on Spatial Learning Memory and Hippocampal Morphology in Offspring Male Rats via PSD95/NR2B Signaling Pathway

Atrazine (ATR), a widely used herbicide, has been previously shown to damage spatial memory capability and the hippocampus of male rats during the development. It has also been indicated that physical exercise can improve learning and memory in both humans and animals, as a neuroprotective method. Our aim here was to investigate the effect of maternal ATR exposure during gestation and lactation on spatial learning and memory function and hippocampal morphology in offspring and to further evaluate the neuroprotective effect of swimming training and identify possible related learning and memory signaling pathways. Using Sprague-Dawley rats, we examined behavioral and molecular biology effects associated with maternal ATR exposure, as well as the effects of 8 or 28 days swimming training. Maternal exposure to ATR was found to impair spatial learning and memory by behavioral test, damage the hippocampal morphology, and reduce related genes and proteins expression of learning and memory in the hippocampus. The extended, 28 days, period of swimming training produced a greater amelioration of the adverse effects of ATR exposure than the shorter, 8 days, training period. Our results suggest that maternal ATR exposure may damage the spatial learning and memory of offspring male rats via PSD95/NR2B signaling pathway. The negative effect of ATR could be at least partially reversed by swimming training, pointing to a potential neuroprotective role of physical exercise in nervous system diseases accompanying by learning and memory deficit.

Memorcise and Alzheimer's disease

Alzheimer's disease (AD) is a debilitating disease influencing a multitude of outcomes, including memory function. Recent work suggests that memory may be influenced by exercise ('memorcise'), even among those with AD. The present narrative review details (1) the underlying mechanisms of AD; (2) whether exercise has a protective effect in preventing AD; (3) the mechanisms through which exercise may help to prevent AD; (4) the mechanisms through which exercise may help attenuate the progression of AD severity among those with existing AD; (5) the effects and mechanisms through which exercise is associated with memory among those with existing AD; and (6) exercise recommendations for those with existing AD. Such an understanding will aid clinicians in their ability to use exercise as a potential behavioral strategy to help prevent and treat AD.

Moderate treadmill exercise ameliorates amyloid-β-induced learning and memory impairment, possibly via increasing AMPK activity and up-regulation of the PGC-1α/FNDC5/BDNF pathway

Alzheimer's disease (AD) is a neurodegenerative disorder associated with loss of memory and cognitive abilities. Previous evidence suggested that exercise ameliorates learning and memory deficits by increasing brain derived neurotrophic factor (BDNF) and activating downstream pathways in AD animal models. However, upstream pathways related to increase BDNF induced by exercise in AD animal models are not well known. We investigated the effects of moderate treadmill exercise on Aβ-induced learning and memory impairment as well as the upstream pathway responsible for increasing hippocampal BDNF in an animal model of AD. Animals were divided into five groups: Intact, Sham, Aβ_1-42, Sham-exercise (Sham-exe) and Aβ_1-42-exercise (Aβ-exe). Aβ was microinjected into the CA1 area of the hippocampus and then animals in the exercise groups were subjected to moderate treadmill exercise (for 4 weeks with 5 sessions per week) 7 days after microinjection. In the present study the Morris water maze (MWM) test was used to assess spatial learning and memory. Hippocampal mRNA levels of BDNF, peroxisome proliferator-activated receptor gamma co-activator 1 alpha (PGC-1α), fibronectin type III domain-containing 5 (FNDC5) as well as protein levels of AMPK-activated protein kinase (AMPK), PGC-1α, BDNF, phosphorylation of AMPK were measured. Our results showed that intra-hippocampal injection of Aβ_1-42 impaired spatial learning and memory which was accompanied by reduced AMPK activity (p-AMPK/total-AMPK ratio) and suppression of the PGC-1α/FNDC5/BDNF pathway in the hippocampus of rats. In contrast, moderate treadmill exercise ameliorated the Aβ_1-42-induced spatial learning and memory deficit, which was accompanied by restored AMPK activity and PGC-1α/FNDC5/BDNF levels. Our results suggest that the increased AMPK activity and up-regulation of the PGC-1α/FNDC5/BDNF pathway by exercise are likely involved in mediating the beneficial effects of exercise on Aβ-induced learning and memory impairment.

Exercise decreases BACE and APP levels in the hippocampus of a rat model of Alzheimer's disease

We investigated the effect of treadmill exercise training on the levels of Alzheimer's disease (AD)-related protein molecules in the DG and CA1 areas of a rat model of AD, i.c.v. infusion of Aβ1-42 peptide, 2weeks (250pmol/day). Aβ infusion markedly increased protein levels of amyloid precursor protein (APP), the secretase beta-site APP cleaving enzyme-1 (BACE-1) and Aβ in the CA1 and DG areas. The results also revealed that 4weeks of treadmill exercise prevented the increase in the levels of APP, BACE-1 and Aβ proteins in both hippocampal areas. Exercise, however, did not affect the levels of these proteins in normal rats. We suggest that exercise might be changing the equilibrium of APP processing pathway towards the nonpathogenic pathway most probably via increasing BDNF levels in the brain of AD model.

An endothelial link between the benefits of physical exercise in dementia

The current absence of a disease-modifying treatment for Alzheimer's disease (AD) and vascular cognitive impairment and dementia (VCID) highlights the necessity for investigating the benefits of non-pharmacological approaches such as physical exercise (PE). Although evidence exists to support an association between regular PE and higher scores on cognitive function tests, and a slower rate of cognitive decline, there is no clear consensus on the underlying molecular mechanisms of the advantages of PE. This review seeks to summarize the positive effects of PE in human and animal studies while highlighting the vascular link between these benefits. Lifestyle factors such as cardiovascular diseases, metabolic syndrome, and sleep apnea will be addressed in relation to the risk they pose in developing AD and VCID, as will molecular factors known to have an impact on either the initiation or the progression of AD and/or VCID. This will include amyloid-beta clearance, oxidative stress, inflammatory responses, neurogenesis, angiogenesis, glucose metabolism, and white matter integrity. Particularly, this review will address how engaging in PE can counter factors that contribute to disease pathogenesis, and how these alterations are linked to endothelial cell function.

Physical exercise as an epigenetic modulator of brain plasticity and cognition

A large amount of evidence has demonstrated the power of exercise to support cognitive function, the effects of which can last for considerable time. An emerging line of scientific evidence indicates that the effects of exercise are longer lasting than previously thought up to the point to affect future generations. The action of exercise on epigenetic regulation of gene expression seem central to building an "epigenetic memory" to influence long-term brain function and behavior. In this review article, we discuss new developments in the epigenetic field connecting exercise with changes in cognitive function, including DNA methylation, histone modifications and microRNAs (miRNAs). The understanding of how exercise promotes long-term cognitive effects is crucial for directing the power of exercise to reduce the burden of neurological and psychiatric disorders.

Exercise as a Positive Modulator of Brain Function

Various forms of exercise have been shown to prevent, restore, or ameliorate a variety of brain disorders including dementias, Parkinson's disease, chronic stress, thyroid disorders, and sleep deprivation, some of which are discussed here. In this review, the effects on brain function of various forms of exercise and exercise mimetics in humans and animal experiments are compared and discussed. Possible mechanisms of the beneficial effects of exercise including the role of neurotrophic factors and others are also discussed.

Modulation of Synaptic Plasticity by Exercise Training as a Basis for Ischemic Stroke Rehabilitation

In recent years, rehabilitation of ischemic stroke draws more and more attention in the world, and has been linked to changes of synaptic plasticity. Exercise training improves motor function of ischemia as well as cognition which is associated with formation of learning and memory. The molecular basis of learning and memory might be synaptic plasticity. Research has therefore been conducted in an attempt to relate effects of exercise training to neuroprotection and neurogenesis adjacent to the ischemic injury brain. The present paper reviews the current literature addressing this question and discusses the possible mechanisms involved in modulation of synaptic plasticity by exercise training. This review shows the pathological process of synaptic dysfunction in ischemic roughly and then discusses the effects of exercise training on scaffold proteins and regulatory protein expression. The expression of scaffold proteins generally increased after training, but the effects on regulatory proteins were mixed. Moreover, the compositions of postsynaptic receptors were changed and the strength of synaptic transmission was enhanced after training. Finally, the recovery of cognition is critically associated with synaptic remodeling in an injured brain, and the remodeling occurs through a number of local regulations including mRNA translation, remodeling of cytoskeleton, and receptor trafficking into and out of the synapse. We do provide a comprehensive knowledge of synaptic plasticity enhancement obtained by exercise training in this review.

Comparison of the Effect of Exercise on Late-Phase LTP of the Dentate Gyrus and CA1 of Alzheimer's Disease Model

We investigated the neuroprotective effect of regular treadmill exercise training on long-term memory and its correlate: the late-phase long-term potentiation (L-LTP) and plasticity- and memory-related signaling molecules in the DG and CA1 areas of a rat model of Alzheimer's disease (AD) (i.c.v. infusion of Aβ_1-42 peptides, 2 weeks, 250 pmol/day). Testing in the radial arm water maze revealed severe impairment of spatial long-term memory in Aβ-infused sedentary rats but not in exercised Aβ-infused rats. The L-LTP, measured as changes in the field (f)EPSP and in the amplitude of population spike (pspike), was induced by multiple high-frequency stimulation in the CA1 and DG areas of anesthetized rats. The L-LTP of fEPSP in both areas was severely impaired in the sedentary Aβ rats but not in exercised Aβ rats. However, L-LTP of the pspike was severely suppressed in the CA1 area but not in the DG of sedentary Aβ rats. Immunoblot analysis revealed no increase in the levels of phosphorylated (p)-CREB, CaMKIV, and brain-derived neurotrophic factor (BDNF) in both CA1 and DG areas of sedentary Aβ rats during L-LTP, whereas the levels of these molecules were robustly increased in exercised Aβ rats. Impairment of synaptic function may be due to deleterious changes in the molecular signaling cascades that mediate synaptic structural and functional changes. The protective effect of regular exercise can be a promising therapeutic measure for countering or delaying the AD-like pathology.

Treadmill exercise enhances synaptic plasticity, but does not alter β-amyloid deposition in hippocampi of aged APP/PS1 transgenic mice

Several studies reveal that the beneficial effects of exercise interventions are dependent on the progression of Alzheimer's disease (AD). We have previously shown that long-term treadmill exercise begun before the onset of β-amyloid (Aβ) pathology prevents the deficits of cognition and long-term potentiation (LTP) in amyloid precursor protein (APP)/presenilin 1 (PS1) transgenic mice (8 months of age) paralleled by the reduction of soluble Aβ levels and Aβ deposition in the hippocampus. In the present study, treadmill exercise was initiated at a developed Aβ deposition stage in order to further investigate whether or not treadmill exercise in this phase can delay the progression of AD in aged APP/PS1 mice (17 months of age). Our results show that 5-month treadmill exercise ameliorates the impairment of spatial learning and memory with age paralleled by synaptic plasticity enhancement in aged APP/PS1 mice. In addition, exercise-induced enhancement of synaptic plasticity was accompanied by a significant reduction of soluble Aβ levels rather than Aβ plaque deposition. Therefore, the investigation demonstrates that long-term treadmill exercise has beneficial effects on cognition and synaptic plasticity even when the brain has developed Aβ deposition, and changes in soluble Aβ levels rather than Aβ plaque deposition may contribute to exercise-induced benefits.