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1.
Life Sci ; 270: 119033, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33497737

RESUMO

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.

2.
Behav Brain Res ; 401: 113085, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33358915

RESUMO

Rehabilitation training is routine for children who experience stroke, but its protective mechanism remains unclear. To study the effect of treadmill training intensity on hippocampal synaptic plasticity after cerebral ischemia, a model of middle cerebral artery occlusion (MCAO)/reperfusion was established in young rats to simulate childhood ischemic stroke. The rats were randomly allocated into five groups: sham operation, MCAO, low-intensity exercise and MCAO (5 m/min), medium-intensity exercise and MCAO (10 m/min), and high-intensity exercise and MCAO (15 m/min). Intervention was continued for 14 days, and a series of experimental tests were conducted. After MCAO, the juvenile rats exhibited a series of morphological and functional alterations, including changes in their neurobehavior and cerebral infarct volumes. Compared with control rats, MCAO rats had a longer escape latency and crossed fewer platforms in the water maze test and exhibited decreased hippocampal neuron density and Synapsin I and PSD95 expression. Furthermore, MCAO rats exhibited synapse morphology changes and abnormal serum levels of lactic acid and corticosterone. Treadmill training effectively reduced the neurobehavioral scores and cerebral infarction volumes, with medium-intensity training showing the best effect. Treadmill training shortened the escape latency, increased the number of platform crossings, and improved the spatial cognitive abilities of the rats, with the medium intensity training having the best effect on spatial learning/memory efficiency. Treadmill training increased the neuron density in the hippocampus, with the medium-intensity training resulting in the highest density. Treadmill training had a positive effect on the expression of Synapsin I and PSD95, with the medium-intensity training showing the strongest effect. Treadmill training improved the sub-microstructure synapse morphology, with the medium-intensity training demonstrating the best effect. Treadmill training increased the plasma levels of lactic acid and corticosterone, with the high-intensity training having the most obvious effect. Treadmill training can provide neuroprotection by promoting hippocampal synaptic plasticity, with medium-intensity training showing the most optimal effects.

3.
Life Sci ; : 118634, 2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33148419

RESUMO

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.

4.
Int J Mol Med ; 45(5): 1447-1463, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32323740

RESUMO

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/ß­catenin pathway) was used to confirm the effects of the Wnt/ß­catenin signaling pathway on exercise­mediated 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 hematoxylin­eosin staining and Nissl staining, and the infarct volume was detected by 2,3,5­triphenyl 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 ß­catenin, brain­derived neurotrophic factor (BDNF) and myelin basic protein (MBP). In addition, XAV939 inhibited treadmill exercise­induced neurogenesis and myelin repair, which was consistent with the downregulation of Wnt3a, nucleus ß­catenin, BDNF and MBP expression, and the deterioration of neurological function. In summary, treadmill exercise promotes neurogenesis and myelin repair by upregulating the Wnt/ß­catenin signaling pathway, to improve the neurological deficit caused by focal cerebral ischemia/reperfusion.

5.
Life Sci ; 243: 117279, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31926245

RESUMO

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.


Assuntos
Autofagia , Proteína Beclina-1/metabolismo , Encéfalo/fisiopatologia , Proteína HMGB1/metabolismo , Fármacos Neuroprotetores , Condicionamento Físico Animal , Animais , Apoptose , Encéfalo/metabolismo , Encéfalo/patologia , Isquemia Encefálica/metabolismo , Masculino , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Traumatismo por Reperfusão/metabolismo
6.
Exp Neurol ; 313: 60-78, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30552877

RESUMO

Dendritic and synaptic plasticity in the penumbra are important processes and are considered to be therapeutic targets of ischemic stroke. Treadmill exercise is known to be a beneficial treatment following stroke. However, its effects and potential mechanism in promoting dendritic and synaptic plasticity remain unknown. We have previously demonstrated that the caveolin-1/VEGF signaling pathway plays a positive role in angiogenesis and neurogenesis. Here, we further investigated the effects of treadmill exercise on promoting dendritic and synaptic plasticity in the penumbra and whether they involve the caveolin-1/VEGF signaling pathway. A middle cerebral artery occlusion (MCAO) animal model was established, and rats were randomly divided into eleven groups. At 2 days after MCAO, rats were subjected to treadmill exercise for 7 or 28 days. Daidzein (a specific inhibitor of caveolin-1, 0.4 mg/kg) was used to confirm the effect of caveolin-1/VEGF signaling on exercise-mediated dendritic and synaptic plasticity. Neurobehavioral performance, tissue morphology and infarct volumes were detected by Modified Neurology Severity Score (mNSS), Hematoxylin-eosin (HE), and Nissl staining, while neural plasticity and its molecular mechanism were examined by Golgi-Cox staining, transmission electron microscopy, western blot analysis and immunofluorescence. We found that treadmill exercise promoted dendritic plasticity in the penumbra, consistent with the significant increase in caveolin-1 and VEGF expression; improved neurological recovery; and reduced infarct volume. In contrast to the positive effects of the treadmill, a caveolin-1 inhibitor abrogated the dendritic and synaptic plasticity. Furthermore, we observed that treadmill exercise-induced improved dendritic and synaptic plasticity were significantly inhibited by the caveolin-1 inhibitor, consistent with the lower expression of caveolin-1 and VEGF, as well as the worse neurobehavioral state. The findings indicate that treadmill exercise ameliorates focal cerebral ischemia/reperfusion-induced neurological deficit by promoting dendritic and synaptic plasticity via upregulating caveolin-1/VEGF signaling pathways.


Assuntos
Caveolina 1/biossíntese , Dendritos/patologia , Terapia por Exercício/métodos , Doenças do Sistema Nervoso/terapia , Plasticidade Neuronal , Traumatismo por Reperfusão/terapia , Sinapses/patologia , Fator A de Crescimento do Endotélio Vascular/biossíntese , Animais , Caveolina 1/antagonistas & inibidores , Caveolina 1/genética , Infarto da Artéria Cerebral Média/complicações , Infarto da Artéria Cerebral Média/patologia , Infarto da Artéria Cerebral Média/terapia , Masculino , Doenças do Sistema Nervoso/etiologia , Doenças do Sistema Nervoso/psicologia , Ratos , Ratos Sprague-Dawley , Recuperação de Função Fisiológica , Traumatismo por Reperfusão/complicações , Traumatismo por Reperfusão/patologia , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/genética
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