Exercise preconditioning reduces neuronal apoptosis in stroke by up-regulating heat shock protein-70 (heat shock protein-72) and extracellular-signal-regulated-kinase 1/2

Molecular chaperones in stroke-induced immunosuppression

Stroke-induced immunosuppression is a process that leads to peripheral suppression of the immune system after a stroke and belongs to the central nervous system injury-induced immunosuppressive syndrome. Stroke-induced immunosuppression leads to increased susceptibility to post-stroke infections, such as urinary tract infections and stroke-associated pneumonia, worsening prognosis. Molecular chaperones are a large class of proteins that are able to maintain proteostasis by directing the folding of nascent polypeptide chains, refolding misfolded proteins, and targeting misfolded proteins for degradation. Various molecular chaperones have been shown to play roles in stroke-induced immunosuppression by modulating the activity of other molecular chaperones, cochaperones, and their associated pathways. This review summarizes the role of molecular chaperones in stroke-induced immunosuppression and discusses new approaches to restore host immune defense after stroke.

Effects of Regular Exercise and Intermittent Fasting on Neurotransmitters, Inflammation, Oxidative Stress, and Brain-Derived Neurotrophic Factor in Cortex of Ovariectomized Rats

A collection of metabolic disorders and neurodegenerative diseases linked to oxidative stress and neuroinflammation frequently affect postmenopausal women or estrogen deprivation. Recent research has focused on alternative therapies that can enhance these women's quality of life. This study set out to investigate the effects of physical exercise (EX) and intermittent fasting (IF) on oxidants/antioxidants, inflammatory cytokines, neurotransmitters, and brain-derived neurotrophic factor (BDNF) in the cortex of rats. Additionally, it sought to assess the response to oxidative stress and neuroinflammation in the brains of rats following ovariectomy (OVX) and the potential mechanisms of these interventions. Fifty female rats were divided into one of the following groups 30 days after bilateral OVX: Control, OVX, OVX + EX, OVX + IF, and OVX + EX + IF groups. The rats in the Control and OVX groups continued their normal activities and had unrestricted access to food and water, but the rats in the OVX + EX and OVX + EX + IF groups had a 4-week treadmill training program, and the rats in the OXV + IF and OVX + EX + IF groups fasted for 13 h each day. The rats were killed, the cerebral cortex was taken, tissue homogenates were created, and various parameters were estimated using these homogenates. The results show that ovariectomized rats had decreased levels of neurotransmitters (DA, NE, and SE), acetylcholinesterase, brain GSH (glutathione), SOD (superoxide dismutase), catalase, GPx (glutathione peroxidase), and TAC (total antioxidant capacity), as well as elevated levels of proinflammatory cytokines and mediators (TNF-α, IL-1β, Cox-2). While ovariectomy-induced declines in neurotransmitters, enzymatic and nonenzymatic molecules, neuroinflammation, and oxidative brain damage were considerably mitigated and prevented by treadmill exercise and intermittent fasting, BDNF was significantly increased. These results suggest that ovariectomy can impair rat neuronal function and regular treadmill exercise and intermittent fasting seem to protect against ovariectomy-induced neuronal impairment through the inhibition of oxidative stress and neuroinflammation and increased BDNF levels in the brain cortex. However, combining regular exercise and intermittent fasting did not provide additional benefits compared to either treatment alone.

The role of microRNA in neuronal inflammation and survival in the post ischemic brain: a review

Each year, more than 790 000 people in the United States suffer from a stroke. Although progress has been made in diagnosis and treatment of ischemic stroke (IS), new therapeutic interventions to protect the brain during an ischemic insult is highly needed. MicroRNAs (miRNAs) are small, non-coding RNAs that regulate gene expression post-transcriptionally. Growing evidence suggests that miRNAs have a profound impact on ischemic stroke progression and are potential targets of novel treatments. Notably, inflammatory pathways play an important role in the pathogenesis of ischemic stroke and its pathophysiologic progression. Experimental and clinical studies have illustrated that inflammatory molecular events collaboratively contribute to neuronal and glial cell survival, edema formation and regression, and vascular integrity. In the present review, we examine recent discoveries regarding miRNAs and their roles in post-ischemic stroke neuropathogenesis.

Transplantation of Exercise-Induced Extracellular Vesicles as a Promising Therapeutic Approach in Ischemic Stroke

Clinical evidence affirms physical exercise is effective in preventive and rehabilitation approaches for ischemic stroke. This sustainable efficacy is independent of cardiovascular risk factors and associates substantial reprogramming in circulating extracellular vesicles (EVs). The intricate journey of pluripotent exercise-induced EVs from parental cells to the whole-body and infiltration to cerebrovascular entity offers several mechanisms to reduce stroke incidence and injury or accelerate the subsequent recovery. This review delineates the potential roles of EVs as prospective effectors of exercise. The candidate miRNA and peptide cargo of exercise-induced EVs with both atheroprotective and neuroprotective characteristics are discussed, along with their presumed targets and pathway interactions. The existing literature provides solid ground to hypothesize that the rich vesicles link exercise to stroke prevention and rehabilitation. However, there are several open questions about the exercise stressors which may optimally regulate EVs kinetic and boost brain mitochondrial adaptations. This review represents a novel perspective on achieving brain fitness against stroke through transplantation of multi-potential EVs generated by multi-parental cells, which is exceptionally reachable in an exercising body.

Ischemic Tolerance—A Way to Reduce the Extent of Ischemia–Reperfusion Damage

Individual tissues have significantly different resistance to ischemia–reperfusion damage. There is still no adequate treatment for the consequences of ischemia–reperfusion damage. By utilizing ischemic tolerance, it is possible to achieve a significant reduction in the extent of the cell damage due to ischemia–reperfusion injury. Since ischemia–reperfusion damage usually occurs unexpectedly, the use of preconditioning is extremely limited. In contrast, postconditioning has wider possibilities for use in practice. In both cases, the activation of ischemic tolerance can also be achieved by the application of sublethal stress on a remote organ. Despite very encouraging and successful results in animal experiments, the clinical results have been disappointing so far. To avoid the factors that prevent the activation of ischemic tolerance, the solution has been to use blood plasma containing tolerance effectors. This plasma is taken from healthy donors in which, after exposure to two sublethal stresses within 48 h, effectors of ischemic tolerance occur in the plasma. Application of this activated plasma to recipient animals after the end of lethal ischemia prevents cell death and significantly reduces the consequences of ischemia–reperfusion damage. Until there is a clear chemical identification of the end products of ischemic tolerance, the simplest way of enhancing ischemic tolerance will be the preparation of activated plasma from young healthy donors with the possibility of its immediate use in recipients during the initial treatment.

Neuroprotective effects of pre-ischemic exercise are linked to expression of NT-3/NT-4 and TrkB/TrkC in rats

INTRODUCTION AND OBJECTIVE

Stroke causes irreversible damage, particularly to the hippocampus. Evidence suggests that exercise training may mitigate adverse structural and functional consequences of an ischemic lesion in the brain. The purpose of this study was to investigate the effects of preconditioning exercise on expression of neurotrophic factor genes and proteins in hippocampalCA1 region and their relationship with sensorimotor recovery following global ischemia/reperfusion (Is/Re) injury in a rat model of stroke.

METHODS

Male Wistar rats were randomly assigned to Exercise+Ischemia/Reperfusion (Ex+Is/Re),Control+Ischemia/Reperfusion (Co+Is/Re), and Sham treatments. Rats in the exercise groups ran on a treadmill for 45 min/d for five days/week for 8 consecutive weeks prior to Is/Re lesion.Ischemia was induced by common carotid artery occlusion (CCAO). The ladder rung walking task was used to assess functional impairments and recovery following ischemic lesion.Tissue from hippocampal area CA1 was inspected for ischemia-induced cell loss and gene and protein expression linked to neurotrophins NT-3, NT-4, and their receptorsTrkB and TrkC.

RESULTS

CCAO caused hippocampal cell death in CA1 and resulted in significant sensori motor impairments in the ladder rung walking task. In contrast, pre-ischemic exercise considerably reduced cell death and supported sensorimotor recovery following CCAO.In addition, NT-3, NT-4,TrkB and TrkC gene expression and their protein levels were significantly increased inthe Ex+Is/Re group compared to Co+Is/Re (p < 0.05).

CONCLUSION

The findings showed that pre-ischemic exercise can exert neuroprotective effects via NT-3 and NT-4 pathways against ischemia in hippocampal CA1 neurons and promote post-injury sensorimotor recovery.

Molecular mechanisms underlying some major common risk factors of stroke

Ischemic and hemorrhagic strokes are the most common known cerebrovascular disease which can be induced by modifiable and non-modifiable risk factors. Age and race are the most common non-modifiable risk factors of stroke. However, hypertension, diabetes, obesity, dyslipidemia, physical inactivity, and cardiovascular disorders are major modifiable risk factors. Understanding the molecular mechanism mediating each of these risk factors is expected to contribute significantly to reducing the risk of stroke, preventing neural damage, enhancing rehabilitation, and designing suitable treatments. Abnormalities in the structure of the blood-brain barrier and blood vessels, thrombosis, vasoconstriction, atherosclerosis, reduced cerebral blood flow, neural oxidative stress, inflammation, and apoptosis, impaired synaptic transmission, excitotoxicity, altered expression/activities of many channels and signaling proteins are the most knows mechanisms responsible for stroke induction. However, the molecular role of risk factors in each of these mechanisms is not well understood and requires a lot of search and reading. This review was designed to provide the reader with a single source of information that discusses the current update of the prevalence, pathophysiology, and all possible molecular mechanisms underlying some major risk factors of stroke namely, hypertension, diabetes mellitus, dyslipidemia, and lipid fraction, and physical inactivity. This provides a full resource for understanding the molecular effect of each of these risk factors in stroke.

Using dual polarities of transcranial direct current stimulation in global cerebral ischemia and its following reperfusion period attenuates neuronal injury

Multiple neuronal injury pathways are activated during cerebral ischemia and reperfusion (I/R). This study was designed to decrease potential neuronal injuries by using both transcranial direct current stimulation (tDCS) polarities in cerebral ischemia and its following reperfusion period. Ninety rats were randomly divided into six groups. In the sham group, rats were intact. In the I/R group, global cerebral I/R was only induced. In the I/R + c-tDCS and I/R + a-tDCS groups, cathodal and anodal currents were applied, respectively. In the I/R + c/a-tDCS, cathodal current was used in the cerebral ischemia and anodal in the reperfusion. In the I/R + a/c-tDCS group, cathodal and anodal currents were applied in the I/R, respectively. Hippocampal tissue was used to determine the levels of IL-1β, TNF-α, NOS, SOD, MDA, and NMDAR. Hot plate and open field tests evaluated sensory and locomotor performances. The cerebral edema was also measured. Histological assessment was assessed by H/E and Nissl staining of the hippocampal CA1 region. All tDCS modes significantly decreased IL-1β and TNF-α levels, especially in the c/a-tDCS. All tDCS caused a significant decrease in MDA and NOS levels while increasing SOD activity compared to the I/R group, especially in the c/a-tDCS mode. In the c-tDCS and a/c-tDCS groups, the NMDAR level was significantly decreased. The c/a-tDCS group improved sensory and locomotor performances more than other groups receiving tDCS. Furthermore, the least neuronal death was observed in the c/a-tDCS mode. Using two different polarities of tDCS could induce more neuroprotective versus pathophysiological pathways in cerebral I/R, especially in c/a-tDCS mode. HIGHLIGHTS: Multiple pathways of neuronal injury are activated in cerebral ischemia and reperfusion (I/R). Using tDCS could modulate neuroinflammation and oxidative stress pathways in global cerebral I/R. Using c/a-tDCS mode during cerebral I/R causes more neuroprotective effects against neuronal injuries of cerebral I/R.

Insight Into the Mechanism of Exercise Preconditioning in Ischemic Stroke

Exercise preconditioning has attracted extensive attention to induce endogenous neuroprotection and has become the hotspot in neurotherapy. The training exercise is given multiple times before cerebral ischemia, effectively inducing ischemic tolerance and alleviating secondary brain damage post-stroke. Compared with other preconditioning methods, the main advantages of exercise include easy clinical operation and being readily accepted by patients. However, the specific mechanism behind exercise preconditioning to ameliorate brain injury is complex. It involves multi-pathway and multi-target regulation, including regulation of inflammatory response, oxidative stress, apoptosis inhibition, and neurogenesis promotion. The current review summarizes the recent studies on the mechanism of neuroprotection induced by exercise, providing the theoretical basis of applying exercise therapy to prevent and treat ischemic stroke. In addition, we highlight the various limitations and future challenges of translational medicine from fundamental study to clinical application.

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.

Mechanisms of Preconditioning Exercise-Induced Neurovascular Protection in Stroke

Ischemic stroke is a leading cause of death and disability. Tissue plasminogen activator is the only U.S. Food and Drug Administration approved thrombolytic therapy for ischemic stroke patients till date. However, its use is limited due to increased risk of bleeding and narrow therapeutic window. Most of the preclinically tested pharmacological agents failed to be translated to the clinic. This drives the need for alternative therapeutic approaches that not only provide enhanced neuroprotection, but also reduce the risk of stroke. Physical exercise is a sort of preconditioning that provides the body with brief ischemic episodes that can protect the body from subsequent severe ischemic attacks like stroke. Physical exercise is known to improve cardiovascular health. However, its role in providing neuroprotection in stroke is not clear. Clinical observational studies showed a correlation between regular physical exercise and reduced risk and severity of ischemic stroke and better outcomes after stroke. However, the underlying mechanisms through which prestroke exercise can reduce the stroke injury and improve the outcomes are not completely understood. The purpose of this review is to: demonstrate the impact of exercise on stroke outcomes and show the potential role of exercise in stroke prevention and recovery; uncover the underlying mechanisms through which exercise reduces the neurovascular injury and improves stroke outcomes aiming to develop novel therapeutic approaches.

Anti-apoptotic and pro-survival effect of exercise training on early aged hypertensive rat cerebral cortex

The anti-apoptotic and pro-survival effects of exercise training were evaluated on the early aged hypertensive rat cerebral cortex. The brain tissues were analysed from ten sedentary male Wistar Kyoto normotensive rats (WKY), ten sedentary spontaneously 12 month early aged hypertensive rats (SHR), and ten hypertensive rats undergoing treadmill exercise training (60 min/day, 5 days/week) for 12 weeks (SHR-EX). TUNEL-positive apoptotic cells, the expression levels of endonuclease G (EndoG) and apoptosis-inducing factor (AIF) (caspase-independent apoptotic pathway), Fas ligand, Fas death receptor, tumor necrosis factor (TNF)-α, TNF receptor 1, Fas-associated death domain, active caspase-8 and active caspase-3 (Fas-mediated apoptotic pathways) as well as t-Bid, Bax, Bak, Bad, cytochrome c, active caspase 9 and active caspase-3 (mitochondria-mediated apoptotic pathways) were reduced in SHR-EX compared with SHR. Pro-survival Bcl2, Bcl-xL, p-Bad, 14-3-3, insulin-like growth factor (IGF)-1, pPI3K/PI3K, and pAKT/AKT were significantly increased in SHR-EX compared to those in SHR. Exercise training suppressed neural EndoG/AIF-related caspase-independent, Fas/FasL-mediated caspase-dependent, mitochondria-mediated caspase-dependent apoptotic pathways as well as enhanced Bcl-2 family-related and IGF-1-related pro-survival pathways in the early aged hypertensive cerebral cortex. These findings indicated new therapeutic effects of exercise training on preventing early aged hypertension-induced neural apoptosis in cerebral cortex.

Preconditioning Exercise in Rats Attenuates Early Brain Injury Resulting from Subarachnoid Hemorrhage by Reducing Oxidative Stress, Inflammation, and Neuronal Apoptosis

Subarachnoid hemorrhage (SAH) is a catastrophic form of stroke responsible for significant morbidity and mortality. Oxidative stress, inflammation, and neuronal apoptosis are important in the pathogenesis of early brain injury (EBI) following SAH. Preconditioning exercise confers neuroprotective effects, mitigating EBI; however, the basis for such protection is unknown. We investigated the effects of preconditioning exercise on brain damage and sensorimotor function after SAH. Male rats were assigned to either a sham-operated (Sham) group, exercise (Ex) group, or no-exercise (No-Ex) group. After a 3-week exercise program, they underwent SAH by endovascular perforation. Consciousness level, neurological score, and sensorimotor function were studied. The expression of nuclear factor erythroid 2 p45-related factor 2 (Nrf2), heme oxygenase 1 (HO-1), 4-hydroxynonenal (4HNE), nitrotyrosine (NT), ionized calcium-binding adaptor molecule 1 (Iba1), tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 1β (IL-1β), 14-3-3γ, p-β-catenin Ser37, Bax, and caspase-3 were evaluated by immunohistochemistry or western blotting. The terminal deoxynucleotidyl transferase-mediated biotinylated dUTP nick end labeling (TUNEL) assay was also performed. After SAH, the Ex group had significantly reduced neurological deficits, sensorimotor dysfunction, and consciousness disorder compared with the No-Ex group. Nrf2, HO-1, and 14-3-3γ were significantly higher in the Ex group, while 4HNE, NT, Iba1, TNF-α, IL-6, IL-1β, Bax, caspase-3, and TUNEL-positive cells were significantly lower. Our findings suggest that preconditioning exercise ameliorates EBI after SAH. The expression of 4HNE and NT was reduced by Nrf2/HO-1 pathway activation; additionally, both oxidative stress and inflammation were reduced. Furthermore, preconditioning exercise reduced apoptosis, likely via the 14-3-3γ/p-β-catenin Ser37/Bax/caspase-3 pathway.

HSP70 inhibition suppressed glioma cell viability during hypoxia/reoxygenation by inhibiting the ERK1/2 and PI3K/AKT signaling pathways

Heat shock protein 70 (HSP70) can regulate astrocyte viability under hypoxic and ischemic conditions. However, the protective mechanism involved is not completely clear. This study aimed to investigate whether HSP70 protects U87 glioma cells against hypoxic damage via the extracellular signal-regulated kinases 1/2 (ERK1/2) and phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) signaling pathways. Lentivirus-mediated HSP70-siRNA was used for HSP70 silencing. U87 glioma cells with lentiviral infection were exposed to hypoxia for 4, 8, 12, and 24 h, respectively, followed by a 24-h reoxygenation treatment. A Cell-Counting Kit-8 was then used to evaluate the viability of the U87 glioma cells. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blotting were performed to determine the mRNA and protein levels, respectively. The expression of HSP70, p-ERK1/2, p-AKT, and U87 cell viability were increased after 8 h of hypoxia/24 h of reoxygenation (P < 0.01). However, HSP70 silencing significantly decreased the U87 cell viability after the hypoxia/reoxygenation treatment (P < 0.01). The protein expressions of p-ERK1/2 and p-AKT also decreased in HSP70-silenced U87 cells (P < 0.01). In conclusion, HSP70 inhibition suppressed the viability of U87 glioma cells during hypoxia/reoxygenation (at least partially) by inhibiting the ERK1/2 and PI3K/AKT signaling pathways. This study may help to understand the molecular mechanisms underlying the progression and development of cerebral hypoxia-ischemia.

Preconditioning increases brain resistance against acute brain injury via neuroinflammation modulation

Acute brain injury (ABI) is a broad concept mainly comprised of sudden parenchymal brain injury. Acute brain injury outcomes are dependent not only on the severity of the primary injury, but the delayed secondary injury that subsequently follows as well. These are both taken into consideration when determining the patient's prognosis. Growing clinical and experimental evidence demonstrates that "preconditioning," a prophylactic approach in which the brain is exposed to various pre-injury stressors, can induce varying degrees of "tolerance" against the impact of the ABI by modulating neuroinflammation. In this review, we will summarize the pathophysiology of ABI, and discuss the involved mechanisms of neuroinflammation in ABI, as well as existing experimental and clinical studies demonstrating the efficacy of preconditioning methods in various types of ABI by modulating neuroinflammation.

Is High-Intensity Interval Training Suitable to Promote Neuroplasticity and Cognitive Functions after Stroke?

Stroke-induced cognitive impairments affect the long-term quality of life. High-intensity interval training (HIIT) is now considered a promising strategy to enhance cognitive functions. This review is designed to examine the role of HIIT in promoting neuroplasticity processes and/or cognitive functions after stroke. The various methodological limitations related to the clinical relevance of studies on the exercise recommendations in individuals with stroke are first discussed. Then, the relevance of HIIT in improving neurotrophic factors expression, neurogenesis and synaptic plasticity is debated in both stroke and healthy individuals (humans and rodents). Moreover, HIIT may have a preventive role on stroke severity, as found in rodents. The potential role of HIIT in stroke rehabilitation is reinforced by findings showing its powerful neurogenic effect that might potentiate cognitive benefits induced by cognitive tasks. In addition, the clinical role of neuroplasticity observed in each hemisphere needs to be clarified by coupling more frequently to cellular/molecular measurements and behavioral testing.

Review Cerebral Ischemic Tolerance and Preconditioning: Methods, Mechanisms, Clinical Applications, and Challenges

Stroke is one of the leading causes of morbidity and mortality worldwide, and it is increasing in prevalence. The limited therapeutic window and potential severe side effects prevent the widespread clinical application of the venous injection of thrombolytic tissue plasminogen activator and thrombectomy, which are regarded as the only approved treatments for acute ischemic stroke. Triggered by various types of mild stressors or stimuli, ischemic preconditioning (IPreC) induces adaptive endogenous tolerance to ischemia/reperfusion (I/R) injury by activating a multitude cascade of biomolecules, for example, proteins, enzymes, receptors, transcription factors, and others, which eventually lead to transcriptional regulation and epigenetic and genomic reprogramming. During the past 30 years, IPreC has been widely studied to confirm its neuroprotection against subsequent I/R injury, mainly including local ischemic preconditioning (LIPreC), remote ischemic preconditioning (RIPreC), and cross preconditioning. Although LIPreC has a strong neuroprotective effect, the clinical application of IPreC for subsequent cerebral ischemia is difficult. There are two main reasons for the above result: Cerebral ischemia is unpredictable, and LIPreC is also capable of inducing unexpected injury with only minor differences to durations or intensity. RIPreC and pharmacological preconditioning, an easy-to-use and non-invasive therapy, can be performed in a variety of clinical settings and appear to be more suitable for the clinical management of ischemic stroke. Hoping to advance our understanding of IPreC, this review mainly focuses on recent advances in IPreC in stroke management, its challenges, and the potential study directions.

Combination of Scalp Acupuncture with Exercise Therapy Effectively Counteracts Ischemic Brain Injury in Rats

BACKGROUND

Stroke is one of the leading causes of death and disability worldwide. Scalp acupuncture and exercise therapy have been proven as two effective methods for the treatment of stroke. However, their combined action and mechanisms have not been fully elucidated. The present study aimed to investigate the protective effect of scalp acupuncture combined with exercise therapy on neurons in rats with ischemic brain injury.

METHODS

100 rats were randomly divided into 5 groups including sham group, model group, acupuncture group, rehabilitation group, and experimental group (scalp acupuncture combined with exercise therapy). Middle cerebral artery occlusion (MCAO) model in rats was established according to Longa modified suture method to mimic ischemic stroke. The modified Bedexer's neurological function score was used to evaluate the neurological deficits of rats and the brain infarct volume was measured using 2, 3, 5-triphenyl tetrazolium chloride monohydrate (TTC) staining. Moreover, the apoptosis in the hippocampus was detected by western blotting and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The pro-inflammatory cytokines such as interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α), reactive oxygen species (ROS) and superoxide dismutase (SOD) were determined by corresponding kits. Immunohistochemistry or immunofluorescence was performed to detect the expression of brain-derived neurotrophic factor (BDNF), S100β and glial fibrillary acidic protein (GFAP) in the hippocampi of rats.

RESULTS

The neurological deficit score, the expression levels of apoptotic factors such as cleaved caspase-3 and Bax, and the TUNEL-positive cell rate of the experimental group were significantly lower than those of the acupuncture group and the rehabilitation group. However, apoptosis inhibitor Bcl-2 showed downregulated expression in the MCAO model rats but this trend was reverted by single and combinatorial treatments. In addition, the contents of TNF-α, IL-1β and ROS in the acupuncture group and the rehabilitation group were significantly lower than those in the model group, but higher than the experimental group. While the opposite results were obtained in SOD activity. Furthermore, compared with the model group, the ratios of BDNF, S100β, and GFAP-positive cells in the acupuncture, rehabilitation and experimental groups were significantly increased, and the highest ratios were recorded in the experimental group.

CONCLUSIONS

This study demonstrated that scalp acupuncture combined with exercise therapy effectively counteracts ischemic brain injury via the downregulation of pro-inflammatory mediators and ROS, the increased production of the antioxidant enzyme SOD, neurotrophic factor BDNF and astrocyte activities.

Remote ischemic conditioning reduced cerebral ischemic injury by modulating inflammatory responses and ERK activity in type 2 diabetic mice

Remote ischemic preconditioning (RIPreC) and postconditioning (RIPostC) have been demonstrated to attenuate brain injury after ischemic stroke in healthy animals. This study investigated whether RIPreC and RIPostC exerted neuroprotection against cerebral ischemic injury in type 2 diabetic mice. RIPreC (24 h before ischemia) and RIPostC (immediately after reperfusion) were performed in an ischemia/reperfusion induced stroke model with type 2 diabetes. Ischemic outcomes, flow cytometry, multiplex cytokine assay, and western blotting were analyzed after 45 min of ischemia followed by 48 h of reperfusion. Our data indicated that RIPreC and RIPostC attenuated cerebral injuries and neurological deficits. RIPreC significantly reduced CD4 T cell and CD8 T cell infiltration and increased B cell infiltration into the ischemic brain. It also upregulated CD4 and CD8 T cell levels in the peripheral blood. However, RIPostC significantly decreased CD8 T cells infiltration and increased B cell infiltration into the ischemic brain. RIPreC inhibited IL-6 level in both the brain and blood, while RIPostC treatment attenuated IL-6 level upregulation in the peripheral blood. In addition, both RIPreC and RIPostC significantly increased p-ERK expression in the ipsilateral hemisphere in diabetic mice. This study indicated that RIPreC and RIPostC neuroprotection is present in type 2 diabetic mice via the modulation of brain ERK activity and inflammatory responses in both the peripheral blood and ischemic brain. However, the benefit was lower in RIPostC.

Short-Term Acute Exercise Preconditioning Reduces Neurovascular Injury After Stroke Through Induced eNOS Activation

Physical exercise is known to reduce cardiovascular risk but its role in ischemic stroke is not clear. It was previously shown that an acute single bout of exercise reduced increased eNOS activation in the heart and reduced myocardial infarction. However, the impact of a single bout or short-term exercise on eNOS-induced neuroprotection after stroke was not previously studied. Accordingly, this study was designed to test the hypothesis that short-term acute exercise can provide "immediate neuroprotection" and improve stroke outcomes through induced eNOS activation. Male Wistar rats (300 g) were subjected to HIIT treadmill exercise for 4 days (25 min/day), break for 2 days, and then one acute bout for 30 min. Exercised animals were subjected to thromboembolic stroke 1 h, 6 h, 24 h, or 72 h after the last exercise session. At 24 h after stroke, control (sedentary) and exercised rats were tested for neurological outcomes, infarct size, and edema. The expression of active eNOS (p-S1177-eNOS) and active AMPK (p-T172-AMPK) was measured in the brain, cerebral vessels, and aorta. In an additional cohort, animals were treated with the eNOS inhibitor, L-NIO (I.P, 20 mg/kg), and stroked 1 h after exercise and compared with non-exercise animals. Acute exercise significantly reduced infarct size, edema, and improved functional outcomes, and significantly increased the expression of peNOS and pAMPK in the brain, cerebral vessels, and aorta. eNOS inhibition abolished the exercise-induced improvement in outcomes. Short-term acute preconditioning exercise reduced the neurovascular injury and improved functional outcomes after stroke through eNOS activation.

Endogenous neuroprotective potential due to preconditioning exercise in stroke

Stroke is a leading cause of serious long-term physical disability due to insufficient neurorepair mechanisms. In general, physical activity is an important modifiable risk factor, particularly for stroke and cardiovascular diseases. Physical exercise has shown to be neuroprotective in both animal experiments and clinical settings. Exercise can be considered a mild stressor and follows the prototypical preconditioning stimulus. It has beneficial effects on brain health and cognitive function. Preconditioning exercise, which is prophylactic exercise prior to ischemia, can protect the brain from subsequent serious injury through promotion of angiogenesis, mediation of inflammatory responses, inhibition of glutamate over-activation, protection of the blood-brain barrier, and inhibition of apoptosis. Preconditioning exercise appears to induce brain ischemic tolerance and it has been shown to exert beneficial effects. It is clinically safe and feasible and represents an exciting new paradigm in endogenous neuroprotection for patients with acute stroke. In this review, we describe the neuroprotective potential of preconditioning exercise and clinical applications in patients with acute ischemic stroke.

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.

Elevated Inflammatory Status and Increased Risk of Chronic Disease in Chronological Aging: Inflamm-aging or Inflamm-inactivity?

Age-associated hyper-inflammation or "inflamm-aging" has been linked to the development of chronic diseases and characterized as an unavoidable aspect of aging. However, the inflamm-aging model does not adequately address the potential anti-inflammatory effects of exercise training and the potential for exercise to ameliorate several age-related diseases. In this brief review, we introduce a new paradigm-inflamm-inactivity-that describes a potent counter-measure to age-associated inflammatory illness.

Ferulic Acid Exerts Anti-apoptotic Effects against Ischemic Injury by Activating HSP70/Bcl-2- and HSP70/Autophagy-Mediated Signaling after Permanent Focal Cerebral Ischemia in Rats

This study assessed the anti-apoptotic effects of the administration of ferulic acid (FrA) in rats 30 min before middle cerebral artery occlusion (MCAo) followed by 3 d of ischemia and the involvement of 70 kDa heat shock protein (HSP70)-mediated signaling in the penumbral cortex. Our results demonstrated that FrA pretreatment at doses of 80 mg/kg (FrA-80 mg) and 100 mg/kg (FrA-100 mg) effectively ameliorated neurological functions and reduced the numbers of cytochrome c-, cleaved caspase-3-, and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells in the penumbral cortex 3 d after ischemia. Moreover, FrA-80 mg and FrA-100 mg pretreatment markedly upregulated cytosolic HSP70, Beclin-1, microtubule-associated protein 1 light chain 3 (LC3) A/B-II and autophagy-related protein 5 (Atg5) expression; cytosolic and mitochondrial X-linked inhibitor of apoptosis (XIAP) expression and the Bcl-2/Bax ratio. FrA pretreatment downregulated cytosolic cytochrome c, apoptosis-inducing factor (AIF), procathepsin B, and cathepsin B expression and mitochondrial and cytosolic second mitochondria-derived activator of caspase/direct inhibitor of apoptosis protein-binding protein with a low isoelectric point (Smac/DIABLO) expression in the penumbral cortex. Pretreatment with VER155008, a HSP70 family inhibitor, significantly inhibited the effects of FrA-100 mg on the expression of the aforementioned proteins expression in the penumbral cortex. FrA-80 mg and FrA-100 mg pretreatment exerts neuroprotective effects against caspase-dependent and -independent apoptosis through activating HSP70/Bcl-2- and HSP70/autophagy-induced signaling pathways. Furthermore, the HSP70/Bcl-2- and HSP70/autophagy-induced anti-apoptotic effects of FrA pretreatment can be attributed to the regulation of Bax/cytochrome c/Smac/DIABLO/XIAP/ caspase-3- (or Bax/AIF-) and Beclin-1/LC3A/B-II/Atg5-mediated signaling, respectively, in the penumbral cortex 3 d after permanent MCAo.

HSP-70-Mediated Hyperbaric Oxygen Reduces Brain and Pulmonary Edema and Cognitive Deficits in Rats in a Simulated High-Altitude Exposure

High-mountain sickness is characterized by brain and pulmonary edema and cognitive deficits. The definition can be fulfilled by a rat model of high-altitude exposure (HAE) used in the present study. This study aimed to investigate the protective effect of hyperbaric oxygen therapy (HBO₂T) and to determine the underlying mechanisms. Rats were subjected to an HAE (9.7% O₂ at 0.47 absolute atmosphere of 6,000 m for 3 days). Immediately after termination of HAE, rats were treated with HBO₂T (100% O₂ at 2.0 absolute atmosphere for 1 hour per day for 5 consecutive days) or non-HBO₂T (21% O₂ at 1.0 absolute atmosphere for 1 hour per day for 5 consecutive days). As compared to non-HAE+non-HBO₂T controls, the HAE+non-HBO₂T rats exhibited brain edema and resulted in cognitive deficits, reduced food and water consumption, body weight loss, increased cerebral inflammation and oxidative stress, and pulmonary edema. HBO₂T increased expression of both hippocampus and lung heat shock protein (HSP-70) and also reversed the HAE-induced brain and pulmonary edema, cognitive deficits, reduced food and water consumption, body weight loss, and brain inflammation and oxidative stress. Decreasing the overexpression of HSP-70 in both hippocampus and lung tissues with HSP-70 antibodies significantly attenuated the beneficial effects exerted by HBO₂T in HAE rats. Our data provide in vivo evidence that HBO₂T works on a remodeling of brain/lung to exert a protective effect against simulated high-mountain sickness via enhancing HSP-70 expression in HAE rats.

Models and methods for conditioning the ischemic brain

BACKGROUND

In the last decades the need to find new neuroprotective targets has addressed the researchers to investigate the endogenous molecular mechanisms that brain activates when exposed to a conditioning stimulus. Indeed, conditioning is an adaptive biological process activated by those interventions able to confer resistance to a deleterious brain event through the exposure to a sub-threshold insult. Specifically, preconditioning and postconditioning are realized when the conditioning stimulus is applied before or after, respectively, the harmul ischemia.

AIMS AND RESULTS

The present review will describe the most common methods to induce brain conditioning, with particular regards to surgical, physical exercise, temperature-induced and pharmacological approaches. It has been well recognized that when the subliminal stimulus is delivered after the ischemic insult, the achieved neuroprotection is comparable to that observed in models of ischemic preconditioning. In addition, subjecting the brain to both preconditioning as well as postconditioning did not cause greater protection than each treatment alone.

CONCLUSIONS

The last decades have provided fascinating insights into the mechanisms and potential application of strategies to induce brain conditioning. Since the identification of intrinsic cell-survival pathways should provide more direct opportunities for translational neuroprotection trials, an accurate examination of the different models of preconditioning and postconditioning is mandatory before starting any new project.

RLIPostC protects against cerebral ischemia through improved synaptogenesis in rats

OBJECTIVE

Remote limb ischemic post-conditioning (RLIPostC) has been shown to be neuroprotective in cerebral ischemia, whereas the effect of RLIPostC on synaptogenesis remains elusive. In the present study, we investigated the effects of RLIPostC on synaptogenesis in an experimental stroke rat model.

METHODS

Sprague-Dawley rats were subjected to left middle cerebral artery occlusion (MCAO) and were randomly divided into a control group, an RLIPostC group and a sham group. The RLIPostC group received three cycles of RLIPostC treatment immediately after reperfusion (ten minutes ischemia and ten minutes reperfusion in bilateral femoral artery). The neurological function was assessed by neurological deficit scores and the foot fault test at days 7 and 14 after MCAO. At day 14 after MCAO, the infarct volume and oedema were determined by cresyl violet (CV) staining and by measuring brain water content, respectively. Synaptogenesis was evaluated by western blotting and immunofluorescence staining.

RESULTS

Our results showed that RLIPostC treatment significantly promoted the recovery of behavioural function, reduced infarct volume and brain oedema, and increased the expressions of SYN1, PSD95 and GAP43.

CONCLUSIONS

These results confirmed that RLIPostC treatment for cerebral ischemia was safe and effective. A possible molecular mechanism of the beneficial effects of RLIPostC treatment may be the promotion of synaptogenesis.

Electroacupuncture Inhibits Apoptosis of Peri-Ischemic Regions via Modulating p38, Extracellular Signal-Regulated Kinase (ERK1/2), and c-Jun N Terminal Kinases (JNK) in Cerebral Ischemia-Reperfusion-Injured Rats

BACKGROUND Previous studies suggested that inhibition of apoptosis prevents the dysfunction of ischemia-reperfusion injury. In the pathogenesis of ischemia-reperfusion injury, JNK/ERK1/2 and p38 play an essential role in regulation of cell apoptosis. Electroacupuncture (EA), a form of acupuncture, has demonstrated superiority in preventing ischemia-reperfusion injury, but the underlying mechanism is unclear. In the present study, we explored the effects of electroacupuncture at Shenting (GV24) and Baihui (GV20) acupoints on focal cerebral ischemia-reperfusion (MCAO) rats, and explored whether JNK/ERK1/2- and p38-mediated cell apoptosis are involved. MATERIAL AND METHODS The rats were divided into a sham operation control group, an ischemia group, and an electroacupuncture group with acupuncture applied for 10 days (30 min per day). TTC staining was used to calculate the ischemic brain volume. TUNEL staining and transmission electron microscopy were used to detect cell apoptosis. Western blot analysis and Bio-Plex were used to detect JNK, p38, ERK1/2, Bcl-2, and Bax protein expression. RESULTS We found that electroacupuncture at day 10 significantly reduced cerebral infarction. In addition, electroacupuncture suppressed activation of JNK and p38, while enhancing the activation of ERK1/2 in the peri-ischemic regions. Consequently, the effect of electroacupuncture on these pathways resulted in the inhibition of apoptosis, which was demonstrated by TUNEL and transmission electron microscopy. We found that electroacupuncture upregulated the anti-apoptotic Bcl-2/Bax ratio in peri-ischemic regions. CONCLUSIONS Our findings suggest that inhibition of cell apoptosis via regulating multiple signaling pathways might be a mechanism whereby electroacupuncture has a positive therapeutic effect on post-stroke impairment.

Analysis of Blood Plasma Protein Composition in Patients with Cerebral Ischemia

Blood plasma proteome in patients with cerebral ischemia and healthy individuals was studied using comparative proteomic analysis based on tandem HPLC-MS/MS. Mass spectra were analysed in an automated mode using Progenesis LS-MS software and 256 proteins were identified. Significant quantitative differences were revealed for 20 proteins. It was found that changes in the blood plasma proteome in subjects with cerebral ischemia involved a wide range of proteins: molecular chaperones, fibrinolysis, angiogenesis, and immune system proteins, proteins involved in homeostasis maintenance, cell differentiation and proliferation, regulators of apoptosis, and cytoskeleton proteins.

The effect of exercise preconditioning on stroke outcome in ovariectomized mice with permanent middle cerebral artery occlusion

Exercise preconditioning has been shown to be effective in improving behavioral and neuropathological indices after cerebral ischemia. We evaluated the effect of exercise preconditioning, 17β-estradiol, and their combination on stroke outcome using an experimental model of stroke in ovariectomized (OVX) mice. OVX mice were randomly assigned to 4 groups as follows: control (stroke), exercise (exercise and stroke), estradiol (17β-estradiol and stroke), and exercise+estradiol (exercise and 17β-estradiol and stroke). Exercise preconditioning was performed on a treadmill 5 days/week, 40 min/day, at a speed of 18 m/min for 4 weeks. 17β-estradiol was gavaged (40 μg/kg per day) for 4 weeks. Stroke was induced by permanent middle cerebral artery occlusion (pMCAO), and neurological deficits were evaluated 1, 2, and 7 days after stroke. Then, the serum concentrations of matrix metalloproteinase-9 (MMP-9) and interleukin-10 (IL-10) and infarct volumes were assessed. Exercise preconditioning and 17β-estradiol induced a better outcome compared with the control ischemic mice, which was manifested by decrease in MMP-9, increase in IL-10, diminished infarct volume, and improved neurological deficits. Concomitant administration of 17β-estradiol and exercise also significantly improved these parameters. Exercise preconditioning or administration of 17β-estradiol alone or in combination before pMCAO induced significant neuroprotection in OVX mice.

Hypoperfusion Induced by Preconditioning Treadmill Training in Hyper-Early Reperfusion After Cerebral Ischemia: A Laser Speckle Imaging Study

Exercise preconditioning induces neuroprotective effects during cerebral ischemia and reperfusion, which involves the recovery of cerebral blood flow (CBF). Mechanisms underlying the neuroprotective effects of re-established CBF following ischemia and reperfusion are unclear. The present study investigated CBF in hyper-early stage of reperfusion by laser speckle contrast imaging, a full-field high-resolution optical imaging technique. Rats with or without treadmill training were subjected to middle cerebral artery occlusion followed by reperfusion. CBF in arteries, veins, and capillaries in hyper-early stage of reperfusion (1, 2, and 3 h after reperfusion) and in subacute stage (24 h after reperfusion) were measured. Neurological scoring and 2,3,5-triphenyltetrazolium chloride staining were further applied to determine the neuroprotective effects of exercise preconditioning. In hyper-early stage of reperfusion, CBF in the rats with exercise preconditioning was reduced significantly in arteries and veins, respectively, compared to rats with no exercise preconditioning. Capillary CBF remained stable in the hyper-early stage of reperfusion, though it increased significantly 24 h after reperfusion in the rats with exercise preconditioning. As a neuroprotective strategy, exercise preconditioning reduced the blood perfusion of arteries and veins in the hyper-early stage of reperfusion, which indicated intervention-induced neuroprotective hypoperfusion after reperfusion onset.

Exercise attenuates neurological deficits by stimulating a critical HSP70/NF-κB/IL-6/synapsin I axis in traumatic brain injury rats

Background

Despite previous evidence for a potent inflammatory response after a traumatic brain injury (TBI), it is unknown whether exercise preconditioning (EP) improves outcomes after a TBI by modulating inflammatory responses.

Methods

We performed quantitative real-time PCR (qPCR) to quantify the genes encoding 84 cytokines and chemokines in the peripheral blood and used ELISA to determine both the cerebral and blood levels of interleukin-6 (IL-6). We also performed the chromatin immunoprecipitation (ChIP) assay to evaluate the extent of nuclear factor kappa-B (NF-κB) binding to the DNA elements in the IL-6 promoter regions. Also, we adopted the Western blotting assay to measure the cerebral levels of heat shock protein (HSP) 70, synapsin I, and β-actin. Finally, we performed both histoimmunological and behavioral assessment to measure brain injury and neurological deficits, respectively.

Results

We first demonstrated that TBI upregulated nine pro-inflammatory and/or neurodegenerative messenger RNAs (mRNAs) in the peripheral blood such as CXCL10, IL-18, IL-16, Cd-70, Mif, Ppbp, Ltd, Tnfrsf 11b, and Faslg. In addition to causing neurological injuries, TBI also upregulated the following 14 anti-inflammatory and/or neuroregenerative mRNAs in the peripheral blood such as Ccl19, Ccl3, Cxcl19, IL-10, IL-22, IL-6, Bmp6, Ccl22, IL-7, Bmp7, Ccl2, Ccl17, IL-1rn, and Gpi. Second, we observed that EP inhibited both neurological injuries and six pro-inflammatory and/or neurodegenerative genes (Cxcl10, IL-18, IL-16, Cd70, Mif, and Faslg) but potentiated four anti-inflammatory and/or neuroregenerative genes (Bmp6, IL-10, IL-22, and IL-6). Prior depletion of cerebral HSP70 with gene silence significantly reversed the beneficial effects of EP in reducing neurological injuries and altered gene profiles after a TBI. A positive Pearson correlation exists between IL-6 and HSP70 in the peripheral blood or in the cerebral levels. In addition, gene silence of cerebral HSP70 significantly reduced the overexpression of NF-κB, IL-6, and synapsin I in the ipsilateral brain regions after an EP in rats.

Conclusions

TBI causes neurological deficits associated with stimulating several pro-inflammatory gene profiles but inhibiting several anti-inflammatory gene profiles of cytokines and chemokines. Exercise protects against neurological injuries via stimulating an anti-inflammatory HSP70/NF-κB/IL-6/synapsin I axis in the injured brains.

Exercise-induced ROS in heat shock proteins response

Cells have evolved multiple and sophisticated stress response mechanisms aiming to prevent macromolecular (including proteins, lipids, and nucleic acids) damage and to maintain or re-establish cellular homeostasis. Heat shock proteins (HSPs) are among the most highly conserved, ubiquitous, and abundant proteins in all organisms. Originally discovered more than 50 years ago through heat shock stress, they display multiple, remarkable roles inside and outside cells under a variety of stresses, including also oxidative stress and radiation, recognizing unfolded or misfolded proteins and facilitating their restructuring. Exercise consists in a combination of physiological stresses, such as metabolic disturbances, changes in circulating levels of hormones, increased temperature, induction of mild to severe inflammatory state, increased production of reactive oxygen and nitrogen species (ROS and RNS). As a consequence, exercise is one of the main stimuli associated with a robust increase in different HSPs in several tissues, which appears to be also fundamental in facilitating the cellular remodeling processes related to the training regime. Among all factors involved in the exercise-related modulation of HSPs level, the ROS production in the contracting muscle or in other tissues represents one of the most attracting, but still under discussion, mechanism. Following exhaustive or damaging muscle exercise, major oxidative damage to proteins and lipids is likely involved in HSP expression, together with mechanically induced damage to muscle proteins and the inflammatory response occurring several days into the recovery period. Instead, the transient and reversible oxidation of proteins by physiological concentrations of ROS seems to be involved in the activation of stress response following non-damaging muscle exercise. This review aims to provide a critical update on the role of HSPs response in exercise-induced adaptation or damage in humans, focusing on experimental results where the link between redox homeostasis and HSPs expression by exercise has been addressed. Further, with the support of in vivo and in vitro studies, we discuss the putative molecular mechanisms underlying the ROS-mediated modulation of HSP expression and/or activity during exercise.

Protecting against ischaemic stroke in rats by heat shock protein 20-mediated exercise

BACKGROUND

Exercise preconditioning (EP(+) ) has been widely accepted as a being of safe and effective preventive measure for stroke. The purpose of this study was to investigate whether EP(+) improves outcomes of ischaemic stroke by promoting neuronal and glial expression of heat shock protein (HSP) 20.

MATERIALS AND METHODS

Adult male Sprague-Dawley rats (288 in number) were used to investigate the contribution of HSP20-containing neurons and HSP20-containing glial cells in the exercise-mediated neuroprotection in the stroke condition using middle cerebral artery occlusion.

RESULTS

Exercise preconditioning, in addition to increasing the numbers of both the HSP20-containg neurons (88 ± 8 vs. 43 ± 4; n = 8 each group; P < 0·05) and the HSP20-containg astrocytes (102 ± 10 vs. 56 ± 5; n = 8; P < 0·05) significantly attenuated stroke-induced brain infarct (140 ± 9 vs. 341 ± 20 mm(3) ; n = 8 per group; P < 0·01), neuronal apoptosis (20 ± 5 vs. 87 ± 7; n = 8 per group; n = 8; P < 0·01), glial apoptosis (29 ± 5 vs. 101 ± 4; n = 8; P < 0·01), and neurological deficits (6·6 ± 0·3 vs. 11·7 ± 0·8; n = 8 per group; P < 0·01). Reducing the numbers of both HSP20-containing neurons and HSP20-contaiing glia by intracerebral injection of pSUPER small interfering RNAί expressing HSP20 significantly reversed the beneficial effects of EP(+) in attenuating stroke-induced cerebral infarct, neuronal and glial apoptosis, and neurological deficits.

CONCLUSIONS

The numbers of both the HSP20-containing neurons and the HSP20-containing glia inversely correlated with the outcomes of ischaemic stroke. In addition, preischaemic treadmill exercise improves outcomes of ischaemic stroke by increasing the numbers of both the HSP20-containing neurons and the HSP20-containing glia.

Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral ischemic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction through occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic exercise significantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.

Treadmill exercise enhances therapeutic potency of transplanted bone mesenchymal stem cells in cerebral ischemic rats via anti-apoptotic effects

Background

The transplantation of bone marrow stromal cells (MSCs) has proved to ameliorate ischemic brain injury in animals, but most transplanted MSCs undergo apoptosis in the ischemic penumbra, greatly compromising the therapeutic value of this treatment. Meanwhile, cell apoptosis can be inhibited by post-ischemia exercise which has been demonstrated to improve the expression of related anti-apoptotic proteins. The present study investigated whether treadmill exercise enhances the neuroprotective effects of transplanted MSCs in a rat experimental stroke model.

Result

Rats were subjected to 2-h middle cerebral artery occlusion (MCAO). Twenty-four hours after reperfusion, they were assigned randomly to receive no MSCs treatment and no exercise (control group), intravenous transplantation of MSCs and treadmill exercise (MSCs + Ex group), MSCs transplantation only (MSCs group) and treadmill exercise only (Ex group). Neurological assessment, TUNEL staining and western blot were performed. Compared with the MSCs group and Ex group, the MSCs + Ex group reported markedly improved neurological function, significantly decreased apoptotic cells, and increased expressions of survivin and bcl-2 (p < 0.05 or p < 0.01, respectively). Interestingly, the treadmill exercise significantly inhibited the apoptosis of transplanted MSCs. As a result, the number of engrafted MSCs in the MSCs + Ex group was significantly higher than that in the MSC group (p < 0.01).

Conclusions

Treadmill exercise enhances the therapeutic potency of MSCs by improving neurological function and possibly inhibiting the apoptosis of neuron cells and transplanted MSCs. These effects may involve an increased expression of survivin and bcl-2.

Decreasing or increasing heat shock protein 72 exacerbates or attenuates heat-induced cell death, respectively, in rat hypothalamic cells

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Mild heat preconditioning up-regulated HSP72 expression in cultured hypothalamic cells.

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siRNA-HSP72 pretreatment down-regulated HSP72 expression.

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Mild heat preconditioning attenuated heat-induced cell loss.

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siRNA-HSP72 pre-treatment exacerbated heat-induced cell loss.

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A positive correlation between HSP72 expression and heat tolerance might exist in hypothalamic cells.

Heat shock protein (HSP) 72 in serum was decreased to a greater degree in patients with serious heat stroke than in those with mild heat stroke. Thus, increased levels of HSP72 appeared to correlate with a better outcome for the patient. Nevertheless, the function of HSP72 in the heat-induced hypothalamic cell death has not been assessed. In this study, we found that increasing HSP72 levels with mild heat preconditioning or decreasing HSP72 levels with pSUPER plasmid expressing HSP72 small interfering RNA significantly attenuated or exacerbated heat-induced cell death in cultured primary hypothalamic cells, respectively. Our findings suggest that HSP72 plays a pivotal role in heat-induced cell death and may be associated with heat tolerance.

Pre-ischemic exercise reduces apoptosis in hippocampal CA3 cells after cerebral ischemia by modulation of the Bax/Bcl-2 proteins ratio and prevention of caspase-3 activation

Ischemia induces physiological alterations in neurons that lead to cell death. This study investigated the effects of pre-ischemic exercise on CA3 neurons. Rats were divided into three groups. Animals in the exercise group were trained 5 days a week for 4 weeks. Ischemia was induced by occlusion of both common carotid arteries (CCAs) for 20 min. Apoptotic cell death was detected by TUNEL assay. Furthermore, expression of different proteins was determined by immunohistochemical staining. The number of TUNEL-positive cells was significantly increased in the ischemia group, but pre-ischemic exercise significantly reduced apoptotic cell death (P < 0.001). In addition, our results showed a significant increase in the Bax/Bcl-2 ratio in the ischemia group. Pre-ischemic exercise attenuated this ratio (P < 0.05). Furthermore, the number of active caspase-3-positive neurons was significantly increased in the ischemia group, which was reduced markedly by exercise preconditioning (P < 0.05). This study showed that pre-ischemic exercise can exert neuroprotective effects against ischemia in CA3 neurons.

Xingshentongqiao decoction mediates proliferation, apoptosis, orexin-A receptor and orexin-B receptor messenger ribonucleic acid expression and represses mitogen-activated protein kinase signaling

BACKGROUND

Hypocretin (HCRT) signaling plays an important role in the pathogenesis of narcolepsy and can be significantly influenced by Chinese herbal therapy. Our previous study showed that xingshentongqiao decoction (XSTQ) is clinically effective for the treatment of narcolepsy. To determine whether XSTQ improves narcolepsy by modulating HCRT signaling, we investigated its effects on SH-SY5Y cell proliferation, apoptosis, and HCRT receptor 1/2 (orexin receptor 1 [OX1R] and orexin receptor 2 [OX2R]) expression. The signaling pathways involved in these processes were also assessed.

METHODS

The effects of XSTQ on proliferation and apoptosis in SH-SY5Y cells were assessed using cell counting kit-8 and annexin V-fluorescein isothiocyanate assays. OX1R and OX2R expression was assessed by quantitative real-time polymerase chain reaction analysis. Western blotting for mitogen-activated protein kinase (MAPK) pathway activation was performed to further assess the signaling mechanism of XSTQ.

RESULTS

XSTQ reduced the proliferation and induced apoptosis of SH-SY5Y cells. This effect was accompanied by the upregulation of OX1R and OX2R expression and the reduced phosphorylation of extracellular signal-regulated kinase (Erk) 1/2, p38 MAPK and c-Jun N-terminal kinase (JNK).

CONCLUSIONS

XSTQ inhibits proliferation and induces apoptosis in SH-SY5Y cells. XSTQ also promotes OX1R and OX2R expression. These effects are associated with the repression of the Erk1/2, p38 MAPK, and JNK signaling pathways. These results define a molecular mechanism for XSTQ in regulating HCRT and MAPK activation, which may explain its ability to treat narcolepsy.

Influence of previous physical activity on the outcome of patients treated by thrombolytic therapy for stroke

Physical activity prevents stroke and is associated with less severe strokes. The neuroprotective effect in patients treated with intravenous (i.v.) recombinant tissue plasminogen activator (rt-PA), remains uncertain. We aimed at evaluating the relationship between previous physical activity and outcomes in stroke patients treated with i.v. rt-PA. OPHELIE-SPORT was a prospective observational multicenter study conducted in French and Japanese stroke patients treated with i.v. rt-PA. We evaluated the presence, weekly duration (<2, 2-5, >5 h) and intensity (light, moderate, heavy) of previous leisure-time physical activity according to standardized criteria. The primary end-point was an excellent outcome [modified Rankin Scale (mRS) 0-1 or similar to the pre-stroke mRS] after 3 months. Secondary end-points were good outcome (mRS 0-2 or similar to the pre-stroke mRS), and death. Of 519 patients, 74 (14.3 %) had regular physical activity before stroke. They were 14 years younger (p < 0.001), treated 25 min earlier (p = 0.004) and more likely to be men, free of pre-stroke handicap (mRS = 0), atrial fibrillation, arterial hypertension, and diabetes mellitus. National Institutes of Health Stroke Scale scores, at baseline (p = 0.183) and 24 h later (p = 0.203), did not differ between patients with and without physical activity. After adjustment on confounders, there was no association between previous leisure-time physical activity and outcome. Outcomes 3 months after treatment of cerebral ischaemia with i.v. rt-PA are not influenced by previous physical activity.