Effects of Treadmill Exercise on Motor and Cognitive Function Recovery of MCAO Mice Through the Caveolin-1/VEGF Signaling Pathway in Ischemic Penumbra

rESWT promoted angiogenesis via Bach1/Wnt/β-catenin signaling pathway

Previous reports have established that rESWT fosters angiogenesis, yet the mechanism by which rESWT promotes cerebral angiogenesis remains elusive. rESWT stimulated HUVECs proliferation as evidenced by the CCK-8 test, with an optimal dosage of 2.0 Bar, 200 impulses, and 2 Hz. The tube formation assay of HUVECs revealed that tube formation peaked at 36 h post-rESWT treatment, concurrent with the lowest expression level of Bach1, as detected by both Western blot and immunofluorescence. The expression level of Wnt3a, β-catenin, and VEGF also peaked at 36 h. A Bach1 overexpression plasmid was transfected into HUVECs, resulting in a decreased expression level of Wnt3a, β-catenin, and VEGF. Upon treatment with rESWT, the down-regulation of Wnt3a, β-catenin, and VEGF expression in the transfected cells was reversed. The Wnt/β-catenin inhibitor DKK-1 was utilized to suppress Wnt3a and β-catenin expression, which led to a concurrent decrease in VEGF expression. However, rESWT treatment could restore the expression of these three proteins, even in the presence of DKK-1. Moreover, in the established OGD model, it was observed that rESWT could inhibit the overexpression of Bach1 and enhance VEGF and VEGFR-2 expression under the OGD environment.

Coenzyme Q10 and exercise training reinstate middle cerebral artery occlusion-induced behavioral deficits and hippocampal long-term potentiation suppression in aging rats

RATIONAL

Patients experience post-stroke cognitive impairment during aging. To date, no specific treatment solution has been reported for this disorder.

OBJECTIVE

The purpose of this study was to evaluate the effects of exercise training and coenzyme Q10 supplementation on middle cerebral artery occlusion (MCAO) induced behavioral impairment, long-term potentiation inhibition and cerebral infarction size in aging rats.

METHODS

Fifty aging male rats underwent MCAO surgery and were randomly distributed in to the following groups: 1-Sham, 2- control, 3- Coenzyme Q10, 4- Exercise training and 5- Exercise training with Q10 supplementation (Ex + Q10). Aerobic training groups were allowed to run on a treadmill for 12 weeks. Q10 (50 mg/kg) was administered intragastrically by gavage. Morris water maze, shuttle box and elevated plus maze tests were used to evaluate cognitive function. The population spike (PS) amplitude and slope of excitatory postsynaptic potentials (EPSP) in the dentate gyrus area were recorded as a result of perforant pathway electrical stimulation.

RESULTS

Our study showed that Q10 and aerobic training alone ameliorate spatial memory in the acquisition phase, but have no effect on spatial memory in the retention phase. Q10 and exercise training synergistically promoted spatial memory in the retention phase. Q10 and exercise training separately and simultaneously mitigated cerebral ischemia-induced passive avoidance memory impairment in acquisition and retention phases. The EPSP did not differ between the groups, but exercise training and Q10 ameliorate the PS amplitude in hippocampal responses to perforant path stimulation. Exercising and Q10 simultaneously reduced the cerebral infarction volume.

CONCLUSION

Collectively, the findings of the present study imply that 12 weeks of aerobic training and Q10 supplementation alone can simultaneously reverse cerebral ischemia induced neurobehavioral deficits via amelioration of synaptic plasticity and a reduction in cerebral infarction volume in senescent rats.

Exercise Reshapes the Brain: Molecular, Cellular, and Structural Changes Associated with Cognitive Improvements

Physical exercise is well known as a non-pharmacological and holistic therapy believed to prevent and mitigate numerous neurological conditions and alleviate ageing-related cognitive decline. To do so, exercise affects the central nervous system (CNS) at different levels. It changes brain physiology and structure, promoting cognitive improvements, which ultimately improves quality of life. Most of these effects are mediated by neurotrophins release, enhanced adult hippocampal neurogenesis, attenuation of neuroinflammation, modulation of cerebral blood flow, and structural reorganisation, besides to promote social interaction with beneficial cognitive outcomes. In this review, we discuss, based on experimental and human research, how exercise impacts the brain structure and function and how these changes contribute to cognitive improvements. Understanding the mechanisms by which exercise affects the brain is essential to understand the brain plasticity following exercise, guiding therapeutic approaches to improve the quality of life, especially in obesity, ageing, neurodegenerative disorders, and following traumatic brain injury.

Effects of aerobic exercise and dietary flavonoids on cognition: a systematic review and meta-analysis

Introduction: Studies have shown that exercise increases angiogenesis and perfusion in the hippocampus, activates neurogenesis in the dentate gyrus and increases synaptic plasticity, as well as increases the complexity and number of dendritic spines, all of which promote memory function and protect against cognitive decline. Flavonoids are gaining attention as antioxidants in health promotion due to their rich phenolic content, particularly for their modulating role in the treatment of neurodegenerative diseases. Despite this, there has been no comprehensive review of cognitive improvement supplemented with flavonoid and prescribed with exercise or a combination of the two interventions has been conducted. The purpose of this review is to determine whether a combined intervention produces better results when given together than when given separately. Methods: Relevant articles assessing the effect of physical exercise, flavonoid or in combination on cognitive related biomarkers and neurobehavioral assessments within the timeline of January 2011 until June 2023 were searched using three databases; PubMed, PROQUEST and SCOPUS. Results: A total of 705 articles were retrieved and screened, resulting in 108 studies which are in line with the objective of the current study were included in the analysis. Discussion: The selected studies have shown significant desired effect on the chosen biomarkers and neurobehavioral assessments. Systematic Review Registration: identifier: [CRD42021271001].

Connexin 43 Promotes Neurogenesis via Regulating Aquaporin-4 after Cerebral Ischemia

We aimed to test the effects of connexin43 (Cx43) on ischemic neurogenesis and examined whether it was dependent on aquaporin-4 (AQP4). We detected the expression of Cx43 and AQP4 in the ipsilateral subventricular zone (SVZ) and peri-infarct cortex after middle cerebral artery occlusion (MCAO). Also, we examined neurogenesis in the above regions via co-labeling of 5-bromo-2-deoxyuridine (BrdU)/neuronal nuclear antigen (NeuN) and BrdU/doublecortin (DCX). The effects of Cx43 and AQP4 were investigated by using two transgenic animals: heterozygous Cx43 (Cx43±) mice and AQP4 knockout (AQP4-/-) mice, and connexin mimetic peptide (CMP), a selective Cx43 blocker. We demonstrated AQP4 and Cx43 were co-expressed in the astrocytes after MCAO and the expression was highly increased in ipsilateral SVZ and peri-infarct cortex. Cx43± mice had larger infarction volumes and worse neurological function. Both BrdU/NeuN and BrdU/DCX co-labeled cells in the two regions were reduced in Cx43± and AQP4-/- mice compared to wild-type (WT) mice, suggesting Cx43 and AQP4 participated in neurogenesis of neural stem cells. Moreover, CMP decreased AQP4 expression and inhibited neurogenesis in WT mice, while the latter failed to be observed in AQP4-/- mice. Besides, higher levels of IL-1β and TNF-α were detected in the SVZ and peri-infarct cortex of AQP4-/- and Cx43± mice than those in WT mice. In conclusion, our data suggest that Cx43 elicits neuroprotective effects after cerebral ischemia through promoting neurogenesis in the SVZ to regenerate the injured neurons, which is AQP4 dependent and associated with down-regulation of inflammatory cytokines IL-1β and TNF-α.

Corticostriatal Projections Relying on GABA Levels Mediate Exercise-Induced Functional Recovery in Cerebral Ischemic Mice

Stroke is a neurological disorder characterized by high disability and death worldwide. The occlusion of the middle cerebral artery (MCAO) supplying the cortical motor regions and its projection pathway regions can either kill the cortical neurons or block their projections to the spinal cord and subcortical structure. The cerebral cortex is the primary striatal afferent, and the medium spiny neurons of the striatum have been identified as the major output neurons projecting to the substantia nigra and pallidum. Thus, disconnection of the corticostriatal circuit often occurs in the model of MCAO. In this study, we hypothesize that striatal network dysfunction in cerebral ischemic mice ultimately modulates the activity of striatal projections from cortical neurons to improve dysfunction during exercise training. In this study, we observed that the corticostriatal circuit originating from glutamatergic neurons could partially medicate the improvement of motor and anxiety-like behavior in mice with exercise. Furthermore, exercising or activating a single optogenetic corticostriatal circuit can increase the striatal gamma-aminobutyric acid (GABA) level. Using the GABA-A receptor antagonist, bicuculline, we further identified that the striatal glutamatergic projection from the cortical neurons relies on the GABAergic synapse's activity to modulate exercise-induced functional recovery. Overall, those results reveal that the dorsal striatum-projecting subpopulation of cortical glutamatergic neurons can influence GABA levels in the striatum, playing a critical role in modulating exercise-induced improvement of motor and anxiety-like behavior.

Synergistic therapeutic effects of intracerebral transplantation of human modified bone marrow-derived stromal cells (SB623) and voluntary exercise with running wheel in a rat model of ischemic stroke

BACKGROUND

Mesenchymal stromal cell (MSC) transplantation therapy is a promising therapy for stroke patients. In parallel, rehabilitation with physical exercise could ameliorate stroke-induced neurological impairment. In this study, we aimed to clarify whether combination therapy of intracerebral transplantation of human modified bone marrow-derived MSCs, SB623 cells, and voluntary exercise with running wheel (RW) could exert synergistic therapeutic effects on a rat model of ischemic stroke.

METHODS

Wistar rats received right transient middle cerebral artery occlusion (MCAO). Voluntary exercise (Ex) groups were trained in a cage with RW from day 7 before MCAO. SB623 cells (4.0 × 105 cells/5 μl) were stereotactically injected into the right striatum at day 1 after MCAO. Behavioral tests were performed at day 1, 7, and 14 after MCAO using the modified Neurological Severity Score (mNSS) and cylinder test. Rats were euthanized at day 15 after MCAO for mRNA level evaluation of ischemic infarct area, endogenous neurogenesis, angiogenesis, and expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). The rats were randomly assigned to one of the four groups: vehicle, Ex, SB623, and SB623 + Ex groups.

RESULTS

SB623 + Ex group achieved significant neurological recovery in mNSS compared to the vehicle group (p < 0.05). The cerebral infarct area of SB623 + Ex group was significantly decreased compared to those in all other groups (p < 0.05). The number of BrdU/Doublecortin (Dcx) double-positive cells in the subventricular zone (SVZ) and the dentate gyrus (DG), the laminin-positive area in the ischemic boundary zone (IBZ), and the mRNA level of BDNF and VEGF in SB623 + Ex group were significantly increased compared to those in all other groups (p < 0.05).

CONCLUSIONS

This study suggests that combination therapy of intracerebral transplantation SB623 cells and voluntary exercise with RW achieves robust neurological recovery and synergistically promotes endogenous neurogenesis and angiogenesis after cerebral ischemia, possibly through a mechanism involving the up-regulation of BDNF and VEGF.

Activation of BDNF- and VEGF-mediated Neuroprotection by Treadmill Exercise Training in Experimental Stroke

Early treatment of ischemic stroke is one of the most effective ways to reduce brains' cell death and promote functional recovery. This study was designed to examine the effect of aerobic exercise on post ischemia/reperfusion injury on concentration and expression of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) after inducing a neuronal loss in CA1 region of hippocampus in Male Wistar rats. Three experimental groups including sham(S), ischemia/reperfusion-control (IRC) and ischemia/reperfusion exercise (IRE) were used for this purpose. The rats in the IRE group received a bilateral carotid artery occlusion treatment. They ran for 45 minutes on a treadmill five days per week for eight consecutive weeks. Cresyl violet (Nissl), Hematoxylin (H & E) and Eosin staining procedure were used to determine the extent of damage. A ladder rung walking task was used to assess the functional impairments and recovery after the ischemic lesion. ELISA and immunohistochemistry method were employed to measure BDNF and VEGF protein expressions. The result showed that the brain ischemia/reperfusion condition increased the cell death in hippocampal CA1 neurons and impaired motor performance on the ladder rung task whereas the aerobic exercise program significantly decreased the brain cell's death and improved motor skill performance. It was concluded that ischemic brain lesion decreased the BDNF and VEGF expression. It seems that the aerobic exercise following the ischemia/reperfusion potentially promotes neuroprotective mechanisms and neuronal repair and survival mediated partly by BDNF and other pathways.

A Shorter-Bout of HIIT Is More Effective to Promote Serum BDNF and VEGF-A Levels and Improve Cognitive Function in Healthy Young Men

Objective: The aim of this study was to investigate the effects of single bouts of high-intensity interval training (HIIT) with different duration on serum brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor-A (VEGF-A) levels and cognitive function in healthy young men.

Methods: Twelve healthy young men were participated in two HIIT treatments (20 min HIIT and 30 min HIIT) in a random order. BDNF, VEGF-A, cortisol, testosterone, blood lactic acid were measured and cognitive function was assessed by Stroop test (CWST) and Digital Span test (DST) before, immediately after, and 30 min after HIIT.

Results: 20 and 30 min HIIT increased BLa (both p < 0.01), cortisol (20 min HIIT: p < 0.05; 30 min HIIT: p < 0.01), and testosterone (both p < 0.05) levels immediately when compared with their baselines. While BLa and cortisol were significantly higher in 30 min HIIT group than in 20 min HIIT group. Moreover, BDNF concentration (p < 0.01), DST-F (p < 0.01) and DST-B (p < 0.05) were increased and response time of Stroop was decreased immediately after HIIT only in 20 min HIIT group. VEGF-A concentration was increased immediately after HIIT in both groups (p < 0.01), but after 30 min recovery, it was returned to the baseline in the 20 min HIIT group and was lower than the baseline in 30 min HIIT group (p < 0.05).

Conclusion: Twenty minutes HIIT is more effective than 30 minutes HIIT for promoting serum levels of BDNF and VEGF-A as well as cognitive function in healthy young men.

Naoluo Xintong Decoction in the Treatment of Ischemic Stroke: A Network Analysis of the Mechanism of Action

The mechanism of action of Naoluo Xintong decoction (NLXTD) for the treatment of ischemic stroke (IS) is unknown. We used network analysis and molecular docking techniques to verify the potential mechanism of action of NLXTD in treating IS. The main active components of NLXTD were obtained from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, and IS targets were collected from the Online Mendelian Inheritance in Man (OMIM), GeneCards, and Drugbank databases; their intersection was taken. In addition, Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed and used to build protein-protein interaction networks. AutoDock Vina software was used for molecular docking, and animal experiments were conducted to verify the results. Hematoxylin and eosin staining was used to observe the brain morphology of rats in each group, and real-time quantitative polymerase chain reaction (RT-qPCR) was used to detect the expression level of relative mRNA in the brain tissue of rats. Western blot was used to detect the expression level of relative protein in the brain tissue of rats. Network analysis and molecular docking results showed that CASP3, NOS3, VEGFA, TNF, PTGS2, and TP53 are important potential targets for NLXTD in the treatment of IS. RT-qPCR and western blot results showed that NLXTD inhibited the expression of CASP3, TNF, PTGS2, and TP53 and promoted the expression of VEGFA and NOS3. NLXTD treats IS by modulating pathways and targets associated with inflammation and apoptosis in a multicomponent, multitarget manner.

Neuroprotective Effect of Physical Activity in Ischemic Stroke: Focus on the Neurovascular Unit

Cerebral ischemia is one of the major diseases associated with death or disability among patients. To date, there is a lack of effective treatments, with the exception of thrombolytic therapy that can be administered during the acute phase of ischemic stroke. Cerebral ischemia can cause a variety of pathological changes, including microvascular basal membrane matrix, endothelial cell activation, and astrocyte adhesion, which may affect signal transduction between the microvessels and neurons. Therefore, researchers put forward the concept of neurovascular unit, including neurons, axons, astrocytes, microvasculature (including endothelial cells, basal membrane matrix, and pericyte), and oligodendrocytes. Numerous studies have demonstrated that exercise can produce protective effects in cerebral ischemia, and that exercise may protect the integrity of the blood-brain barrier, promote neovascularization, reduce neuronal apoptosis, and eventually lead to an improvement in neurological function after cerebral ischemia. In this review, we summarized the potential mechanisms on the effect of exercise on cerebral ischemia, by mainly focusing on the neurovascular unit, with the aim of providing a novel therapeutic strategy for future treatment of cerebral ischemia.

Exercise Intervention Promotes the Growth of Synapses and Regulates Neuroplasticity in Rats With Ischemic Stroke Through Exosomes

Background: Stroke is the leading cause of death and disability. Exercise produces neuroprotection by improving neuroplasticity. Exercise can induce exosome production. According to several studies, exosomes are involved in repairing brain function, but the relationship and mechanism of exercise, exosomes, and neuroprotection have not been elucidated. This study intends to explore the relationship and potential mechanism by observing the changes in the exosome level, infarct volume, neurological function and behavioral scores, synapses, and corticospinal tract (CST).

Methods: Rats were randomly divided into four groups: a sham operation (SHAM) group, middle cerebral artery occlusion (MCAO) with sedentary intervention (SED-MCAO) group, MCAO with exercise intervention (EX-MCAO) group, and MCAO with exercise intervention and exosome injection (EX-MCAO-EXO) group. The exercise intervention was started 1 day after MCAO and lasted for 4 weeks. All rats were assessed using the modified neurological severity score (mNSS). The levels of exosomes in serum and brain, gait analysis, and magnetic resonance scan were performed 1 and 4 weeks after the intervention. After 4 weeks of intervention, the number of synapses, synaptophysin (Syn), and postsynaptic density protein 95(PSD-95) expression was detected.

Results: After 4 weeks of intervention, (1) the EX-MCAO and EX-MCAO-EXO groups showed higher serum exosome (p_EX−MCAO = 0.000, p_{EX−MCAO−EXO} = 0.000) and brain exosome (p_EX−MCAO = 0.001, p_{EX−MCAO−EXO} = 0.000) levels than the SED-MCAO group, of which the EX-MCAO group had the highest serum exosome (p = 0.000) and the EX-MCAO-EXO group had the highest brain exosome (p = 0.03) levels. (2) The number of synapses in the EX-MCAO (p = 0.032) and EX-MCAO-EXO groups (p = 0.000) was significantly higher than that in the SED-MCAO group. The EX-MCAO-EXO group exhibited a greater number of synapses than the EX-MCAO (p = 0.000) group. (3) The synaptic plasticity-associated proteins were expressed significantly higher in the EX-MCAO (p_Syn = 0.010, p_PSD−95 = 0.044) and EX-MCAO-EXO (p_Syn = 0.000, p_PSD−95 = 0.000) groups than in the SED-MCAO group, and the EX-MCAO-EXO group (p_Syn = 0.000, p_PSD−95 = 0.046) had the highest expression. (4) Compared with the SED-MCAO group, the EX-MCAO group had significantly improved infarct volume ratio (p = 0.000), rFA value (p = 0.000), and rADC (p = 0.000). Compared with the EX-MCAO group, the EX-MCAO-EXO group had a significantly improved infarct volume ratio (p = 0.000), rFA value (p = 0.000), and rADC value (p = 0.001). (5) Compared with the SED-MCAO group, the EX-MCAO group (p = 0.001) and EX-MCAO-EXO group (p = 0.000) had significantly lower mNSS scores and improved gait. (6) The brain exosome levels were negatively correlated with the mNSS score, infarct volume ratio, and rADC value and positively correlated with the rFA value, Syn, and PSD-95 expression. The serum and brain exosome levels showed a positive correlation.

Conclusions: Exercise intervention increases the serum exosome level in MCAO rats, which are recruited into the brain, leading to improved synaptic growth and CST integrity, a reduced infarct volume, and improved neurological function and gait.

Astrocytic A1/A2 paradigm participates in glycogen mobilization mediated neuroprotection on reperfusion injury after ischemic stroke

Background

Astrocytic glycogen works as an essential energy reserve for surrounding neurons and is reported to accumulate excessively during cerebral ischemia/reperfusion (I/R) injury. Our previous study found that accumulated glycogen mobilization exhibits a neuroprotective effect against I/R damage. In addition, ischemia could transform astrocytes into A1-like (toxic) and A2-like (protective) subtypes. However, the underlying mechanism behind accumulated glycogen mobilization-mediated neuroprotection in cerebral reperfusion injury and its relationship with the astrocytic A1/A2 paradigm is unknown.

Methods

Astrocytic glycogen phosphorylase, the rate-limiting enzyme in glycogen mobilization, was specifically overexpressed and knocked down in mice and in cultured astrocytes. The I/R injury was imitated using a middle cerebral artery occlusion/reperfusion model in mice and an oxygen–glucose deprivation/reoxygenation model in cultured cells. Alterations in A1-like and A2-like astrocytes and the expression of phosphorylated nuclear transcription factor-κB (NF-κB) and phosphorylated signal transducer and activator of transcription 3 (STAT3) were determined by RNA sequencing, immunofluorescence and immunoblotting. Metabolites, including glycogen, NADPH, glutathione and reactive oxygen species (ROS), were analyzed by biochemical analysis.

Results

Here, we observed that astrocytic glycogen mobilization inhibited A1-like astrocytes and enhanced A2-like astrocytes after reperfusion in an experimental ischemic stroke model in vivo and in vitro. In addition, glycogen mobilization could enhance the production of NADPH and glutathione by the pentose phosphate pathway (PPP) and reduce ROS levels during reperfusion. NF-κB inhibition and STAT3 activation caused by a decrease in ROS levels were responsible for glycogen mobilization-induced A1-like and A2-like astrocyte transformation after I/R. The astrocytic A1/A2 paradigm is closely correlated with glycogen mobilization-mediated neuroprotection in cerebral reperfusion injury.

Conclusions

Our data suggest that ROS-mediated NF-κB inhibition and STAT3 activation are the key pathways for glycogen mobilization-induced neuroprotection and provide a promising metabolic target for brain reperfusion injury in ischemic stroke.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-021-02284-y.

Neuroplastic Effect of Exercise Through Astrocytes Activation and Cellular Crosstalk

Physical exercise is an effective therapy for neurorehabilitation. Exercise has been shown to induce remodeling and proliferation of astrocyte. Astrocytes potentially affect the recruitment and function of neurons; they could intensify responses of neurons and bring more neurons for the process of neuroplasticity. Interactions between astrocytes, microglia and neurons modulate neuroplasticity and, subsequently, neural circuit function. These cellular interactions promote the number and function of synapses, neurogenesis, and cerebrovascular remodeling. However, the roles and crosstalk of astrocytes with neurons and microglia and any subsequent neuroplastic effects have not been studied extensively in exercise-induced settings. This article discusses the impact of physical exercise on astrocyte proliferation and highlights the interplay between astrocytes, microglia and neurons. The crosstalk between these cells may enhance neuroplasticity, leading to the neuroplastic effects of exercise.

Exercise Prior to Lower Extremity Peripheral Artery Disease Improves Endurance Capacity and Hindlimb Blood Flow by Inhibiting Muscle Inflammation

Lower extremity peripheral artery disease (PAD) is associated with functional decline. Physical exercise has been proven to be an effective therapeutic strategy for PAD; however the effect of exercise initiated before PAD remains unknown. Here, we investigated the preventive effects of exercise on endurance capacity, hindlimb perfusion, and on polarization profile of circulating monocytes and limb muscle macrophages. ApoE^−/− mice were subjected to 5-week running wheel exercise or remained sedentary before induction of hindlimb ischemia. The two groups were thereafter kept sedentary. Exercised mice prior to PAD showed higher exhaustive treadmill running distance and time than sedentary mice. Preventive exercise also increased perfusion, arteriole density, and muscle regeneration in the ischemic hindlimb. Moreover, preventive exercise prevented ischemia-induced increased gene expression of pro-inflammatory M1 macrophages markers and cytokines in the ischemic muscle, while no changes were observed for anti-inflammatory M2 macrophage markers. Flow cytometry analysis showed that the proportion of circulating pro-inflammatory monocyte subtype decreased whereas that of anti-inflammatory monocytes increased with preventive exercise. Overall, we show that exercise initiated before PAD improves endurance performance and hindlimb perfusion in mice probably via inhibition of M1 macrophage polarization and inflammation in the ischemic muscle. Our study provides experimental evidence for a role of regular exercise in primary prevention of PAD.

Voluntary running exercise after focal cerebral ischemia ameliorates dendritic spine loss and promotes functional recovery

Cerebral infarction causes motor, sensory, and cognitive impairments. Although rehabilitation enhances recovery of activities of daily living after cerebral infarction, its mechanism remains elusive due to the lack of reproducibility and low survival rate of brain ischemic model animals. Here, to investigate the relationship between rehabilitative intervention, motor function, and pathophysiological remodeling of the tissue in the ipsilateral hemisphere after cerebral infarction, we took advantage of a highly reproducible model of cerebral infarction using C.B-17/Icr-^+/+Jcl mice. In this model, we confirmed that voluntary running exercise improved functional recovery after ischemia. Exercise did not alter the volume of infarction or survived cortex, or the number of NeuN-labeled cells in the peri-infarct cortex. In mice who did not exercise, the number of basal dendritic spines of layer 5 pyramidal cells decreased in the peri-infarct motor cortex, whereas in mice who exercised it remained at the normal level. The voluntary exercise intervention maintained basal dendritic spine density within the peri-infarct area, which may reflect an adaptive remodeling of the surviving neural circuitry that might contribute to promoting the recovery of activities of daily living.

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.

Treadmill exercise enhances synaptic plasticity in the ischemic penumbra of MCAO mice by inducing the expression of Camk2a via CYFIP1 upregulation

AIMS

Physical exercise is beneficial to the recovery of patients with ischemic stroke. However, the underlying mechanism by which exercise promotes dendritic remodeling and synaptic plasticity is still obscure. This study explored the mechanism by which treadmill exercise enhances synaptic plasticity and dendritic remodeling in the ischemic penumbra.

MAIN METHODS

A middle cerebral artery occlusion (MCAO) model was generated in C57BL/6 mice, and lentivirus-mediated cytoplasmic FMRP-associated protein 1 (CYFIP1) shRNA expression was utilized to confirm the role of CYFIP1 in the exercise-induced increase in synaptic plasticity and dendritic remodeling. Neurological deficits were measured using the Zea Longa scale. Hematoxylin-eosin (H&E) staining and Nissl staining were performed to assess cerebral ischemic injury. Golgi-Cox staining was used to observe changes in dendritic remodeling and synaptic plasticity. Transmission electron microscopy (TEM) was performed to observe the synaptic ultrastructure. Molecular mechanisms were explored using immunofluorescence staining and western blotting.

KEY FINDINGS

Treadmill training enhanced synaptic plasticity in the penumbra. Additionally, we observed significant increases in the expression of CYFIP1 and calcium/calmodulin-dependent kinase 2a (Camk2a); enhanced neurological recovery and a decreased infarct volume. However, the injection of a lentivirus containing CYFIP1 shRNA into the lateral ventricle exerted negative effects on synaptic plasticity. Moreover, the exercise-induced neuroprotective effects were abolished by lentivirus-mediated CYFIP1 shRNA expression, consistent with the downregulation of Camk2a expression and the deterioration of neurological function.

SIGNIFICANCE

Treadmill training enhances synaptic plasticity and dendritic remodeling in the ischemic penumbra by inducing the expression of Camk2a via upregulation of CYFIP1.

Cognitive Gains of Aerobic Exercise in Patients With Ischemic Cerebrovascular Disorder: A Systematic Review and Meta-Analysis

Background: Cognitive impairment has become an important problem in ischemic cerebrovascular disorder survivors as disease related deaths have been significantly reduced. Aerobic exercise, the most prevalent mode of physical activity, positively contributes to cognition in both healthy population and people with cognitive impairment. However, studies on its associations with cognitive gains in patients with ischemic cerebrovascular disease showed mixed findings.

Objective: To explore the cognitive effects of aerobic exercise on ischemic cerebrovascular disorder survivors and investigate the possible moderators on exercise benefits.

Method: Randomized controlled trials investigating the effects of sole aerobic exercise on cognitive function in population with ischemic intracranial vascular disorder compared to any control group who did not receive the intervention were enrolled in this systematic review and meta-analysis. Four online database (Pubmed, Cochrane Library, Embase, and Web of Science) were searched.

Results: The initial search returned 1,522 citations and ultimately 11 studies were included in the systematic review. Analysis of seven studies showed the beneficial but not statistically significant impact of aerobic exercise on global cognitive function (0.13; 95% Cl −0.09 to 0.35; p = 0.25). Participants already with cognitive impairment benefited more from this intervention (0.31; 95% Cl 0.07–0.55; p = 0.01) and moderate intensity might be the optimal choice (0.34; 95% Cl −0.01 to 0.69; p = 0.06). The program duration and initiation time after stroke occurrence did not predict better cognitive outcome. Aerobic exercise was not associated with improvement of processing speed and executive function, the two subdomains of cognitive function.

Conclusions: Aerobic exercise may contribute to cognitive gains in survivors of ischemic cerebrovascular disorder, especially for population already with cognitive decline. Our findings suggest that the adoption of moderate intensity aerobic exercise might improve cognition in such population.

Treadmill exercise attenuates cerebral ischaemic injury in rats by protecting mitochondrial function via enhancement of caveolin-1

AIMS

Exercise training has a neuroprotective effect against ischaemic injury, but the underlying mechanism is not completely clear. This study explored the potential mechanisms underlying the protective effects of treadmill training and caveolin-1 regulation against mitochondrial dysfunction in cerebral ischaemic injury.

MAIN METHODS

After middle cerebral artery occlusion (MCAO) surgery, rats were subjected to treadmill training and received daidzein injections and combined therapy. A series of analyses, including neurological function scoring; body weight measurement; Nissl, haematoxylin and eosin staining; cerebral infarction volume assessment; mitochondrial morphology examination; caveolin-1, cytoplasmic and mitochondrial cytochrome C (CytC), and translocase of outer membrane 20 (TOM20) expression analysis; apoptosis index analysis; and transmission electron microscopy were conducted.

KEY FINDINGS

Treadmill training increased caveolin-1 expression, reduced neurobehavioral scores and cerebral infarction volumes, improved tissue morphology, reduced neuronal loss, inhibited mitochondrial outer membrane permeabilization (MOMP) through the caveolin-1 pathway, prevented excessive Cyt-C release from mitochondria, and reduced the degrees of apoptosis and mitochondrial damage. In addition, treadmill training increased the expression of TOM20 through the caveolin-1 pathway and maintained import signal function, thereby protecting mitochondrial integrity.

SIGNIFICANCE

Treadmill exercise protected mitochondrial integrity and inhibited the endogenous mitochondrial apoptosis pathway. The damage of cerebral ischaemia was alleviated in rats through enhancement of caveolin-1 by treadmill exercise.

Treadmill exercise ameliorates chronic REM sleep deprivation-induced anxiety-like behavior and cognitive impairment in C57BL/6J mice

Various sleep disorders have deleterious effects on mental and cognitive performance. Exercise, as an alternative therapeutic strategy, exerts beneficial impacts on human health. In the present study, we aimed to evaluate the effects of 4 weeks treadmill exercise (4W-TE) on anxiety-like behavior and cognitive performance in mice exposed to 2 months REM sleep deprivation (2M-SD) (20 h per day). Behavioral performance of mice in elevated plus maze test (EPM), open field test (OFT), Y maze test (YM) and Morris water maze test (MWM) was recorded and analyzed 28 h after the last day of sleep deprivation. After behavioral tests, various neurotransmitters including norepinephrine (NE), dopamine (DA), serotonin (5-HT) and γ-aminobutyric acid (GABA) in mouse hippocampus were quantified using high performance liquid chromatography. The hippocampal levels of insulin-like growth factor-1 (IGF-1) and brain derived neurotrophic factor (BDNF) were further detected using ELISA. Behavioral data indicated that 2M-SD exposure induced anxiety-like behaviors and cognitive impairment, as evidenced by the decreased open-arm entries in EPM, reduced central area travels in OFT, declined spontaneous alteration in YM and prolonged escaping latency in MWM. In addition, 2M-SD exposure increased NE and DA, decreased 5-HT and GABA, and reduced IGF-1 and BDNF levels in mouse hippocampus. Interestingly, all these behavioral, neurochemical and neurobiological changes can be ameliorated by 4W-TE training. In summary, these findings confirm the beneficial impacts of exercise on health and provide further experimental evidence for future application of exercise as an alternative therapy against the mental and cognitive problems in patients with sleep disorders.

A Review of Exercise-Induced Neuroplasticity in Ischemic Stroke: Pathology and Mechanisms

After ischemic stroke, survivors experience motor dysfunction and deterioration of memory and cognition. These symptoms are associated with the disruption of normal neuronal function, i.e., the secretion of neurotrophic factors, interhemispheric connections, and synaptic activity, and hence the disruption of the normal neural circuit. Exercise is considered an effective and feasible rehabilitation strategy for improving cognitive and motor recovery following ischemic stroke through the facilitation of neuroplasticity. In this review, our aim was to discuss the mechanisms by which exercise-induced neuroplasticity improves motor function and cognitive ability after ischemic stroke. The associated mechanisms include increases in neurotrophins, improvements in synaptic structure and function, the enhancement of interhemispheric connections, the promotion of neural regeneration, the acceleration of neural function reorganization, and the facilitation of compensation beyond the infarcted tissue. We also discuss some common exercise strategies and a novel exercise therapy, robot-assisted movement, which might be widely applied in the clinic to help stroke patients in the future.

Cell-Autonomous Autophagy Protects Against Chronic Intermittent Hypoxia Induced Sensory Nerves and Endothelial Dysfunction of the Soft Palate

BACKGROUND Chronic intermittent hypoxia (CIH) is a key feature of obstructive sleep apnea (OSA) syndrome. The pathogenesis of CIH-induced soft palate lesion is not well understood. Understanding the mechanisms of CIH-induced soft palate damage could provide new strategies for clinical treatment. MATERIAL AND METHODS Twenty male Sprague‑Dawley rats were randomized into a control group (n=10) and experimental group (n=10). The experimental group were exposed to CIH for 28 days. The control experiments were run in parallel. Morphological changes of CIH-induced soft palate were examined by hematoxylin and eosin. Peripheral nerves and vascular associated markers were analyzed by western blot and immunohistochemical staining. LC3B expression and transmission electron microscopy analysis was detected to investigate the destiny of cells in CIH-induced soft palate. RESULTS Histological studies demonstrated the thicken mucosal layer, muscular changes consistent with glands hyperplasia, and loose connective tissues of the soft palate in CIH induced rat models. CIH exposure significantly decreased the expression of annexin V but did not change argin level, suggesting that sensory nerves not motor nerves were damaged when exposed to intermittent hypoxia. Moreover, in response to CIH, the vascular vessel around the nerves and muscles became enlarged and caveolin-1 was overexpressed. Autophagy occurs in response to CIH-induced neuromuscular and vascular endothelial injury. CONCLUSIONS Sensory nerves and endothelial dysfunction contributed to the morphological damage of soft palate under intermittent hypoxia. Autophagy as a compensatory mechanism protects against CIH-induced injury. These findings have important implications for understanding mechanisms contributing to the increased soft palate lesion in patients with OSA.

Caveolin as a Novel Potential Therapeutic Target in Cardiac and Vascular Diseases: A Mini Review

Caveolin, a structural protein of caveolae, play roles in the regulation of endothelial function, cellular lipid homeostasis, and cardiac function by affecting the activity and biogenesis of nitric oxide, and by modulating signal transduction pathways that mediate inflammatory responses and oxidative stress. In this review, we present the role of caveolin in cardiac and vascular diseases and the relevant signaling pathways involved. Furthermore, we discuss a novel therapeutic perspective comprising crosstalk between caveolin and autophagy.

Different exercises can modulate the differentiation/maturation of neural stem/progenitor cells after photochemically induced focal cerebral infarction

INTRODUCTION

Exercise therapies during rehabilitation significantly promote recovery from various deficits after cerebral infarction, which is mediated by neuronal plasticity with distinct inputs. Although adult neurogenesis can also be modulated by neuronal activity before synaptogenesis, how distinct exercises contribute to the neurological reorganization of the injured cerebral cortex remains unclear. In the present study, we aimed to elucidate the effects of different exercise therapies on motor recovery and neuronal reorganization after photochemically induced focal cerebral infarction.

METHODS

Here, we examined the effects of three different exercises-(a) forced lower-intensity and (b) higher-intensity treadmill exercises, and (c) voluntary exercise with wheel running-on motor recovery and adult neurogenesis in a rat model of focal cerebral infarction. Photochemically induced thrombosis (PIT) was used to generate focal infarction in rats that was mostly confined to their motor cortices.

RESULTS

Beam walking tests showed that recovery after PIT-induced cortical infarction differed in acute and chronic stages and was influenced by the type of exercise. Furthermore, forced low-intensity training had more positive effects on functional recovery than other exercises or control. To evaluate the production of newly generated cells including de novo neurogenesis, we performed lineage analysis with BrdU labeling and immunofluorescence experiments. Lower-intensity treadmill exercise increased the number of BrdU/NeuN colabeled cells, but not total BrdU-retaining or BrdU/Sox2-colabeled cells, in the peri-infarct region of the ipsilateral cortex. In contrast, high-intensity treadmill or voluntary exercises had the opposite effects.

CONCLUSIONS

These results suggest that neuronal maturation can be differently modulated by distinct exercises and that low-intensity treadmill exercise could result in more potent generation of mature neurons. This also suggests the possibility that the generation of neural stem/progenitor cells and differentiation might be modulated by rehabilitation-mediated neural plasticity.

Treadmill exercise promotes neurogenesis and myelin repair via upregulating Wnt/β‑catenin signaling pathways in the juvenile brain following focal cerebral ischemia/reperfusion

Physical exercise has a neuroprotective effect and is an important treatment after ischemic stroke. Promoting neurogenesis and myelin repair in the penumbra is an important method for the treatment of ischemic stroke. However, the role and potential mechanism of exercise in neurogenesis and myelin repair still needs to be clarified. The goal of the present study was to ascertain the possible effect of treadmill training on the neuroprotective signaling pathway in juvenile rats after ischemic stroke. The model of middle cerebral artery occlusion (MCAO) in juvenile rats was established and then the rats were randomly divided into 9 groups. XAV939 (an inhibitor of the Wnt/β‑catenin pathway) was used to confirm the effects of the Wnt/β‑catenin signaling pathway on exercise‑mediated neurogenesis and myelin repair. Neurological deficits were detected by modified neurological severity score, the injury of brain tissue and the morphology of neurons was detected by hematoxylin‑eosin staining and Nissl staining, and the infarct volume was detected by 2,3,5‑triphenyl tetrazolium chloride staining. The changes in myelin were observed by Luxol fast blue staining. The neuron ultrastructure was observed by transmission electron microscopy. Immunofluorescence and western blots analyzed the molecular mechanisms. The results showed that treadmill exercise improved neurogenesis, enhanced myelin repair, promoted neurological function recovery and reduced infarct volume. These were the results of the upregulation of Wnt3a and nucleus β‑catenin, brain‑derived neurotrophic factor (BDNF) and myelin basic protein (MBP). In addition, XAV939 inhibited treadmill exercise‑induced neurogenesis and myelin repair, which was consistent with the downregulation of Wnt3a, nucleus β‑catenin, BDNF and MBP expression, and the deterioration of neurological function. In summary, treadmill exercise promotes neurogenesis and myelin repair by upregulating the Wnt/β‑catenin signaling pathway, to improve the neurological deficit caused by focal cerebral ischemia/reperfusion.

Role of Caveolin-1 in Diabetes and Its Complications

It is estimated that in 2017 there were 451 million people with diabetes worldwide. These figures are expected to increase to 693 million by 2045; thus, innovative preventative programs and treatments are a necessity to fight this escalating pandemic disorder. Caveolin-1 (CAV1), an integral membrane protein, is the principal component of caveolae in membranes and is involved in multiple cellular functions such as endocytosis, cholesterol homeostasis, signal transduction, and mechanoprotection. Previous studies demonstrated that CAV1 is critical for insulin receptor-mediated signaling, insulin secretion, and potentially the development of insulin resistance. Here, we summarize the recent progress on the role of CAV1 in diabetes and diabetic complications.

Treadmill exercise improves neurological function by inhibiting autophagy and the binding of HMGB1 to Beclin1 in MCAO juvenile rats

AIMS

Treadmill exercise is a beneficial treatment following childhood stroke. Thus, studies focusing on the neuroprotective mechanism of exercise training during postischemic treatment in children with ischemic stroke are urgently needed. We evaluated the effects of treadmill exercise on autophagy after cerebral ischemia in young rats.

MAIN METHODS

Rats (23-25 days old) underwent cerebral ischemia-reperfusion (CI/R) surgery. The experimental animals were divided into 5 groups, and some groups received either treadmill exercise, a rapamycin (RAPA) injection or combination therapy for 3 or 7 days. We performed a series of experimental tests including neurological scoring, hematoxylin-eosin staining (H&E), Nissl staining, triphenyl tetrazolium chloride (TTC) staining, Western blot analysis (WB), immunofluorescence (IF), enzyme-linked immunosorbent assay (ELISA), transmission electron microscopy (TEM) and Terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) fluorescence.

KEY FINDINGS

The experimental data indicated that treadmill exercise inhibited autophagy in the ischemic penumbra, inhibited high mobility group box 1 (HMGB1) translocation and binding to Beclin1, reduced apoptosis, reduced infarct volumes, and aided in functional recovery. However, RAPA promoted the opposite effects of treadmill exercise.

SIGNIFICANCE

We found that treadmill exercise improves the neurological deficits induced by CI/R by inhibiting autophagy and HMGB1 binding to Beclin1.

Sex-Dependent Differences in Physical Exercise-Mediated Cognitive Recovery Following Middle Cerebral Artery Occlusion in Aged Rats

Stroke remains a leading cause of death and disability in the United States. No current treatments exist to promote cognitive recovery in survivors of stroke. A previous study from our laboratory determined that an acute bout of forced treadmill exercise was able to promote cognitive recovery in 3 month old male rats after middle cerebral artery occlusion (MCAo). In this study, we tested the hypothesis that 6 days of intense acute bout of forced treadmill exercise (physical exercise – PE) promotes cognitive recovery in 11–14 month old male rats. We determined that PE was able to ameliorate cognitive deficits as determined by contextual fear conditioning. Additionally, we also tested the hypothesis that PE promotes cognitive recovery in 11–13 month old reproductive senescent female rats. In contrast to males, the same intensity of exercise that decrease cognitive deficits in males was not able to promote cognitive recovery in female rats. Additionally, we determined that exercise did not lessen infarct volume in both male and female rats. There are many factors that contribute to higher stroke mortality and morbidities in women and thus, future studies will investigate the effects of PE in aged female rats to identify sex differences.

A brief physical activity protects against ischemic stroke

With restricted therapeutic opportunities, stroke remains a relevant, critical disease necessitating study. Due to the unique aspect of ischemic strokes, finding approaches to maintain the vigor of the cerebral vasculature, such as increased angiogenesis, may protect against stroke. Ischemic strokes are caused by disruptions in blood movement in the brain, resulting in a torrent of harmful cerebrovasculature modifications. In an investigation by Pianta et al., Sprague-Dawley rats have been separated into those that undergo exercise prior to middle cerebral artery occlusion (MCAO) and those that were not exposed to physical activity preceding MCAO. The outcomes and results of the current study gave new insights into the capacity of exercise to help prevent ischemic strokes or mitigate poststroke effects. The data collected from the study suggested that rats that went through a short bout of exercise before MCAO presented superior motor performance, more active cells in the peri-infarct region, and reduced infarct sizes. When compared to the control group, the rats that went through exercise also had heightened angiogenesis and improved neuroprotection. Thus, a brief bout of physical activity preceding a stroke may provide neuroprotection by enhancing the strength of the cerebrovasculature in the brain. This notion that even an instant of physical exercise before a stroke is induced can help dampen the effects of ischemic stroke, which could lead to future techniques in preventing the ischemic stroke so that it never happens at all.

Buyang Huanwu Decoction Exerts Cardioprotective Effects through Targeting Angiogenesis via Caveolin-1/VEGF Signaling Pathway in Mice with Acute Myocardial Infarction

Background

Acute myocardial infarction (AMI) remains a leading cause of morbidity and mortality worldwide. The idea of therapeutic angiogenesis in ischemic myocardium is a promising strategy for MI patients. Buyang Huanwu decoction (BHD), a famous Chinese herbal prescription, exerted antioxidant, antiapoptotic, and anti-inflammatory effects, which contribute to cardio-/cerebral protection. Here, we aim to investigate the effects of BHD on angiogenesis through the caveolin-1 (Cav-1)/vascular endothelial growth factor (VEGF) pathway in MI model of mice.

Materials and Methods

C57BL/6 mice were randomly divided into 3 groups by the table of random number: (1) sham-operated group (sham, n = 15), (2) AMI group (AMI+sham, n = 20), and (3) BHD-treated group (AMI+BHD, n = 20). 2,3,5-Triphenyltetrazolium chloride solution stain was used to determine myocardial infarct size. Myocardial histopathology was tested using Masson staining and hematoxylin-eosin staining. CD31 immunofluorescence staining was used to analyze the angiogenesis in the infarction border zone. Western blot analysis, immunofluorescence staining, and/or real-time quantitative reverse transcription polymerase chain reaction was applied to test the expression of Cav-1, VEGF, vascular endothelial growth factor receptor 2 (VEGFR2), and/or phosphorylated extracellular signal-regulated kinase (p-ERK). All statistical analyses were performed using the SPSS 20.0 software and GraphPad Prism 6.05. Values of P < 0.05 were considered as statistically significant.

Results and Conclusion

Compared with the AMI group, the BHD-treated group showed a significant improvement in the heart weight/body weight ratio, echocardiography images, cardiac function, infarct size, Mason staining of the collagen deposition area, and density of microvessel in the infarction border zone (P < 0.05). Compared with the AMI group, BHD promoted the expression of Cav-1, VEGF, VEGFR2, and p-ERK in the infarction border zone after AMI. BHD could exert cardioprotective effects on the mouse model with AMI through targeting angiogenesis via Cav-1/VEGF signaling pathway.

A Short Bout of Exercise Prior to Stroke Improves Functional Outcomes by Enhancing Angiogenesis

Stroke remains a significant unmet clinical need with limited therapeutic options. The peculiar feature of ischemic stroke is the interruption in brain circulation, resulting in a cascade of detrimental cerebrovasculature alterations. Treatment strategies designed to maintain potency of the cerebrovasculature may protect against stroke. The present study assessed the effects of short bouts of exercise prior to stroke induction and characterized cerebral blood flow and motor functions in vivo. Adult Sprague-Dawley rats were exposed to a single short bout of exercise (30-min or 60-min forced running wheel) then subjected to transient middle cerebral artery occlusion (MCAO). Non-exercise stroke rats served as controls while non-stroke rats represented shams. Cerebral blood flow (CBF) was evaluated by laser Doppler at baseline (prior to MCAO), during MCAO, and during reperfusion. Behavioral tests using the elevated body swing test was conducted at baseline, day 0 (day of stroke), and at days 1 and 3 after stroke. Animals that received exercise displayed typical alterations in CBF after stroke, but exhibited improved motor performance compared to non-exercise rats. Exercised stroke rats showed a reduction in infarct size and an increased number of surviving cells in the peri-infarct area, with a trend towards prolonged duration of the exercise. Immunofluorescence staining and Western blot analysis of the peri-infarct area revealed increased levels of endothelial markers/angiogenesis markers, VEGF, VEGFR-2, and Ang-2, and endothelial progenitor cell marker CD34+ in exercise groups compared with the controls. These results demonstrated that prophylactic exercise affords neuroprotection possibly by improving cerebrovascular potency.