Cerebral Ischemia-reperfusion Injury Model Research Articles

Basic Research on Neuroprotective Effect of Volatile Oil of Cang Ai after Cerebral Ischemia-Reperfusion Injury Based on Diffusion Tensor Imaging

To study the neuroprotective effect of inhalation of volatile oil of Cang Ai (VOCA) on cerebral ischemia-reperfusion injury model by MRI diffusion tensor imaging. Twenty-four healthy adult male SD rats were randomly divided into sham operation group, model (middle cerebral artery occlusion (MCAO) ) group and VOCA group. Evaluated the degree of neurological impairment of rats in each group immediately after successful establishment of model or 7 d later according to Zea Longa scoring. Coronal diffusion tensor imaging (DTI) scan was performed at 3 h, 3 d, and 7 d after the model successfully established by using 7.0 T magnetic resonance imaging. Measured the apparent diffusion coefficient (ADC) and anisotropy score (FA) of the DTI in the striatal region and the motion flat zone of the maximum infarct level and then calculate the relative apparent diffusion coefficient (rADC) and relative anisotropy score (rFA). TTC staining was used to evaluate the cerebral infarction volume of rats in each group at 7 d post model establishment, and the correlation analysis of rFA, rADC and neural score was performed. No neurological defect was detected in mice in the sham operation group. The MCAO group and the VOCA group showed neurological defect to different degrees. The neurological function score of the VOCA group was obviously lower than that of MCAO group at 7 th day (P<0.05). The DTI scan results showed that the rADC value of striatum of rats in VOCA group was higher than that in MCAO group at 3 h and 3 d after modeling (P<0.05), while there was no significant difference between the three groups at 7 th day. The rADC value of the motor cortex in the VOCA group was higher than that in the MCAO group at 3 h after modeling (P<0.01), and there was no significant difference at 3 rdday and 7 thday. The rFA value of striatum in VOCA group was higher than that in MCAO group at 3 rd day and 7 th day after modeling (P<0.05). There were no significant differences in rFA value between the MCAO and the VOCA group at three time points. TTC staining results showed that there was no infarcted area in the sham operation group, and the infarct volume in the VOCA group was smaller than that of the MCAO group (P<0.05). Correlation analysis showed that the striatum rFA value was highly correlated with neurological scores (r=－0.847, P<0.01). For the first time, we found that VOCA can effectively protect the neurological function of MCAO rats by reducing the toxic edema of cells in the ischemic area and accelerating the recovery of nerve fiber bundles after cerebral ischemia and reperfusion. rFA and rADC values can be used as effective indicators to evaluate the recovery of nerve function after cerebral ischemia and reperfusion.

Identification of differentially expressed miRNA 48 h after cerebral ischemia-reperfusion injury in mice by the technique of miRNA microarray.

The objective was to identify the differential expressed miRNA during cerebral ischemia-reperfusion injury (CIRI) process, thereby assisting in elucidating the mechanism of CIRI development and providing a potential target for CIRI prevention and treatment. Six mice were randomly assigned to two groups: control group and CIRI model group. A global cerebral IR model by four-vessel occlusion was prepared among the CIRI model group. Brain tissues were collected 48 h after reperfusion. Total RNA was extracted for each sample. miRNA microarrays were employed to detect the differentially expressed miRNA between the CIRI group and the control group. One differentially expressed miRNA was selected for verification by PCR. Compared with the control group, 69 miRNAs were significantly differential expressed in samples of the CIRI group, among which 50 miRNAs were upregulated and 19 miRNAs were downregulated. The real-time qPCR results indicated that the results of the miRNA microarray were reliable. A number of miRNAs were significantly regulated in the CIRI model, which suggested that miRNA was closely associated with the pathological alterations after ischemia. These identified miRNAs may provide directions and targets for the future pathological research of CIRI.

Inhibition of IL-32 Expression Ameliorates Cerebral Ischemia-Reperfusion Injury via the NOD/MAPK/NF-κB Signaling Pathway.

Cerebral ischemia represents a major cause of disability, yet its precise mechanism remains unknown. In addition, ischemia-reperfusion injury which occurs during the blood recovery process increases the risk of mortality, and is not adequately addressed with current treatment. To improve therapeutic options, it is important to explore the vital substances that play a pivotal role in ischemia-reperfusion injury. This study is the first to investigate the role of IL-32, a vital pro-inflammatory factor, in models of cerebral ischemia-reperfusion injury. The results showed that IL-32 was highly expressed in both in vivo and in vitro models. The proteins of the NOD/MAPK/NF-κB pathway were also up-regulated, indicating a potential signaling pathway mechanism. Inhibition of IL-32 and blocking of the NOD/MAPK/NF-κB pathway increased cell survival, decreased the level of inflammatory factors and inflammasomes, and attenuated nitrosative stress. Taken together, the results show that inhibition of IL-32 expression ameliorates cerebral ischemia-reperfusion injury via the NOD/MAPK/NF-κB signaling pathway. The findings in this study reveal that IL-32 is a vital target of ischemia-reperfusion injury, providing a new avenue for treatment development.

Lung SOD3 limits neurovascular reperfusion injury and systemic immune activation following transient global cerebral ischemia

Background and ObjectivesStudies implicate the lung in moderating systemic immune activation via effects on circulating leukocytes. In this study, we investigated whether targeted expression of the antioxidant extracellular superoxide dismutase (SOD3) within the lung would influence post-ischemic peripheral neutrophil activation and CNS reperfusion injury. MethodsAdult, male mice expressing human SOD3 within type II pneumocytes were subjected to 15 min of transient global cerebral ischemia. Three days post-reperfusion, lung and brain tissue was collected and analyzed by immunohistochemistry for inflammation and injury markers. In vitro motility and neurotoxicity assays were conducted to ascertain the direct effects of hSOD3 on PMN activation. Results were compared against C57BL/6 age and sex-matched controls. ResultsRelative to wild-type controls, hSOD3 heterozygous mice exhibited a reduction in lung inflammation, blood-brain barrier damage, and post-ischemic neuronal injury within the hippocampus and cortex. PMNs harvested from hSOD3 mice were also resistant to LPS priming, slower-moving, and less toxic to primary neuronal cultures. ConclusionsConstitutive, focal expression of hSOD3 is neuroprotective in a model of global cerebral ischemia-reperfusion injury. The underlying mechanism of SOD3-dependent protection is attributable in part to effects on the activation state and toxic potential of circulating neutrophils. These results implicate lung-brain coupling as a determinant of cerebral ischemia-reperfusion injury and highlight post-stroke lung inflammation as a potential therapeutic target in acute ischemic cerebrovascular injuries.

MicroRNA-579-3p Exerts Neuroprotective Effects Against Ischemic Stroke via Anti-Inflammation and Anti-Apoptosis.

Background/AimsMultiple studies have found that microRNAs (miRNAs) are involved in the development of cerebral ischemia. MiR-579-3p can inhibit inflammatory responses and apoptosis, leading to ischemia/reperfusion (I/R) damage. However, the mechanism of how miR-579-3p actions in brain I/R injury remains unclear. This study aimed to investigate the mechanism of the role of miR-579-3p in brain I/R injury.MethodsA rat model of cerebral ischemia–reperfusion injury was established by suture method. The effects of miR-579-3p on cerebral infarction size, brain water content, and neurological symptoms were evaluated. Flow cytometry was used to detect apoptosis. ELISA was used to detect the level of inflammatory factors. Western blot was used to detect the expression of P65, NCOA1, Bcl-2 and Bax. The relationship between miR-579-3p and NCOA1 was analyzed by bioinformatics analysis and luciferase assay.ResultsOverexpression of miR-579-3p reduced infarct volume, brain water content and neurological deficits. Overexpression of miR-579-3p inhibited the expression level of the inflammatory cytokines, such as TNF-α, IL-6, COX-2 and iNOS, and increased the expression level of IL-10. MiR-579-3p overexpression inhibited NF-кB activity by reducing NRIP1. In addition, miR-579-3p could reduce the apoptotic rate of cortical neurons. Overexpression of miR-579-3p inhibited the activity of caspase-3, increased the expression level of anti-apoptotic gene Bcl-2 in neurons, and decreased the expression level of apoptotic gene Bax.ConclusionmiR-579-3p can be used to treat brain I/R injury, and its neuroprotective effect may be ascribed to the reduction of inflammation and apoptosis.

Total glucosides of paeony (Paeonia lactiflora) alleviates blood-brain barrier disruption and cerebral ischemia/reperfusion injury in rats via suppressing inflammation and apoptosis.

At present it remains uncertain as to whether total glucosides of paeony (TGP) are able to mediate neuroprotection in the context of cerebral ischemia/reperfusion (CIR) injury, and if so, what mechanisms underlie such protection. We employed a rat model of middle cerebral artery occlusion and reperfusion, and then Evans blue (EB), hematoxylin and eosin, Nissl staining, TUNEL staining, ELISAs and immunohistochemistry were used. We observed marked reductions in infarct volume, neurological deficits, and CIR-associated histopathological changes following TGP treatment. We further found that TGP was associated with restoration of the BBB integrity, a reduction in levels of cerebral IL-1β, IL-6 and TNF-α, and a decrease in overall neuronal apoptotic death that coincided with reduced Cleaved Caspase-3 and Bax expression, and elevated Bcl-2. These results demonstrate that TGP treatment is capable of reducing neurons damage and associated BBB dysfunction via anti-apoptotic and anti-inflammatory mechanisms in a rodent model of CIR injury.

Lidocaine improves cerebral ischemia-reperfusion injury in rats through cAMP/PKA signaling pathway

Influence of lidocaine on rats with cerebral ischemia-reperfusion injury (CIRI) was studied to explore its mechanism of action. A total of 30 Sprague-Dawley rats were randomly divided into control group and model group, and the rat model of CIRI was prepared by the suture-occluded method in the model group. Then the rats in the model group were randomly assigned into the model group (n=10) and the lidocaine group (n=10). The neurological function score of rats was evaluated, and the levels of serum B-cell lymphoma-2 (Bcl-2) and Bcl-2 associated X protein (Bax) in rats were determined using ELISA. TUNEL assay was performed to detect the neuronal apoptosis in the brain of rats. The messenger ribonucleic acid (mRNA) and protein expression levels of cyclic adenosine monophosphate (cAMP) and protein kinase A (PKA) were measured via RT-PCR and western blotting, respectively. Compared with those in the control group, the rats in the model group had an elevated neurological function score, a raised level of Bcl-2, but a reduced level of Bax in the serum, an obviously increased rate of neuronal apoptosis in the brain and decreased mRNA and protein levels of cAMP and PKA in cerebral tissues. The rats in lidocaine group had a lower neurological function score, a lower level of Bcl-2, but a higher level of Bax in the serum, an evidently lower rate of neuronal apoptosis in the brain and higher mRNA and protein levels of cAMP and PKA in cerebral tissues than those in the model group. Lidocaine can improve the neurological function of rats with CIRI and inhibit neuronal apoptosis in the brain, and its mechanism of action may be related to the activation of the cAMP/PKA signaling pathway.

RETRACTED ARTICLE: Astragalin alleviates cerebral ischemia-reperfusion injury by improving anti-oxidant and anti-inflammatory activities and inhibiting apoptosis pathway in rats

BackgroundAstragalin (AG), a flavonoid from many traditional herbs and medicinal plants, has been described to exhibit in vitro anti-inflammatory activity. The paper aimed to study the effects of astragalin on anti-inflammatory, anti-oxidative ability and apoptosis signaling pathway in brain tissue of rats with cerebral ischemia-reperfusion injury, and to explore its possible mechanism.MethodsThe rat model of focal cerebral ischemia-reperfusion injury was established by suture method. It was randomly divided into 5 groups, sham operation group, ischemia-reperfusion (I/R) treatment group, and astragalin treatment I / R group (12.5, 25, 50 mg / kg). After 24 h of reperfusion, the neurological deficits of the rats were analyzed and HE staining was performed. The volume of cerebral infarction was calculated by triphenyltetrazolium chloride (TTC) staining, and the apoptosis of nerve cells was detected by TUNEL staining. In addition, the content of malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), glutathione (GSH) assay and glutathione peroxidase (GSH-Px) were measured in rat brain tissue. Western blot analysis was used to determine the expression of related proteins.ResultsCompared with I/R group, the neurological deficit score and infarct volume of I/R rats were reduced in the astragalin treatment group. In the astragalin treatment group, MDA and NO levels in I/R rats were reduced, antioxidant enzymes and superoxide dismutase (SOD) activity were increased. In the astragalin treatment group, NF-κB (p65) and cyclooxygenase-2 (COX-2) expression levels were down-regulated, NF-E2-related factor 2 (Nrf2) nucleus and heme oxygenase-1 (HO-1) protein expression levels were up-regulated. In addition, the astragalin treatment can inhibit apoptosis, down-regulate Bax and cleaved caspase-3 expression, up-regulate Bcl-Xl expression.ConclusionThe antioxidant properties of astragalin may play an important role in improving cerebral ischemia-reperfusion injury.

Research on mechanism of sevoflurane in alleviating cerebral ischemia-reperfusion injury in rats through JNK signaling pathway.

To explore the specific mechanism of sevoflurane in alleviating cerebral ischemia-reperfusion injury (CIRI) in rats through the c-Jun N-terminal kinase (JNK) signaling pathway. A total of 60 male specific pathogen-free Sprague-Dawley rats were randomly divided into sham group (n=20), model group (n=20), and sevoflurane group (n=20). In the sevoflurane group, sevoflurane (2.5%) was inhaled for 60 min at 24 h before the blockage of cerebral blood supply. The CIRI model was established using the suture method in the model group and sevoflurane group, while the right common carotid artery and external carotid artery were separated and ligated only, without suture placement, in the sham group. At 24 h after reperfusion, the neurological deficit score in each group was calculated, the water content in brain tissues in each group was detected based on dry-wet weight ratio, the infarction volume of brain tissues in each group was detected via 2,3,5-triphenyltetrazolium chloride (TTC) staining, and the apoptosis rate of brain cells in each group was detected using terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. Moreover, the protein levels of JNK, p-JNK, B-cell lymphoma-2 (Bcl-2), and the Bcl-2 associated X protein (Bax) in brain tissues were determined using Western blotting, and the gene expressions of Bax and Bcl-2 in brain tissues were determined through fluorescence quantitative Polymerase Chain Reaction (qPCR). It was found that the water content in brain tissues and the cerebral infarction volume were significantly increased in the model group compared with those in the sham group (p<0.01, p<0.01), while they were notably decreased in the sevoflurane group compared with those in the model group (p<0.05, p<0.01). The neurological deficit score was significantly higher in the model group than that in the sham group (p<0.01), while it was remarkably lower in the sevoflurane group than that in the model group (p<0.01). According to the results of the TUNEL assay, the model group had an evidently higher apoptosis rate of brain cells than the sham group (p<0.01), while the sevoflurane group had a lower apoptosis rate of brain cells than the model group (p<0.05). Besides, the results of Western blotting revealed that the model group exhibited remarkably increased protein levels of JNK, p-JNK, and Bax (p<0.05, p<0.01, p<0.01) and a remarkably decreased protein level of Bcl-2 (p<0.01) compared with the sham group. Sevoflurane group had decreased protein levels of JNK, p-JNK, and Bax (p<0.05, p<0.01, p<0.01) and an increased protein level of Bcl-2 (p<0.05) in comparison with the model group. In addition, the gene expression of Bcl-2 significantly declined (p<0.01), and that of Bax remarkably rose (p<0.01) in the model group compared with those in the sham group, while the contrary is the case in the sevoflurane group compared with those in the model group (p<0.05, p<0.01). Sevoflurane can regulate the protein and gene expressions of Bax and Bcl-2 and reduce apoptosis in CIRI by regulating the JNK signaling pathway, thereby exerting a protective effect on brain tissues and improving the symptoms of neurological deficit.

Effect of Erdene urel on Microglia / Macrophage Distribution and Inhibition of Inflammatory Response after Brain Ischemia in Rats

Objectives: We studied the effect of Erdene urel on microglia/macrophage M1/M2 distribution and neuroinflammation using a cerebral ischemia-reperfusion injury model in rats. Methods: The middle cerebral artery occluded by thread occlusion, followed by reperfusion at 90 minutes after ischemia. The injury was studied at 1, 3, and 7 days after brain ischemia, and the neurological score was graded, after that, the brain tissue was collected by decollation. The phenotypes of M1 and M2 were detected by Iba1 and Arg-1 immunofluorescence, and the expressions of (TNF-D), (IL-1E), (IL-6), and (IL-10) were detected by ELISA. Result: The immunofluorescence showed that compared with the sham-operated group, the microglia/ macrophage (Iba1) in the ischemic area of the control group’s rats with middle cerebral artery occlusion and to which reperfusion was performed for 1, 3 and 7 days was increased (p&lt;.05) and the number of M2 (Arg-1) (p&lt;.05) was reduced. One day after reperfusion, the Erdene urel and nimodipine groups did not differ from the control group. However, after 3 and 7 days, the microglia/macrophage (Iba1) (p&lt;.05) in the ischemic area of Erdene urel and nimodipine groups was reduced, while M2 (Arg-1) (p&lt;.05) was increased. Conclusion: Erdene urel is likely capable of promoting the transformation of activated microglia/macrophages from M1 to M2.

Baicalin ameliorates neuropathology in repeated cerebral ischemia-reperfusion injury model mice by remodeling the gut microbiota

We investigated the neuroprotective effects of baicalin and the role of gut microbiota in a mouse model of cerebral ischemia-reperfusion injury. Repeated cerebral ischemia-reperfusion significantly increased plasma levels of trimethylamine (TMA), trimethylamine-N-oxide (TMAO), and clusterin (a neuroinflammation biomarker). These changes correlated with cognitive decline; short-term memory deficits; abnormal long term potentiation (LTP); decreased functional connectivity (FC) between various brain regions; reduced plasticity and dendritic spine density in the hippocampus; increased levels of the pro-inflammatory cytokines IL-1β, IL-6, and TNFα; and altered the gut microbial composition. Treatment with 50-100 mg/Kg baicalin for 7 days after cerebral ischemia-reperfusion significantly restored normal plasma levels of TMA, TMAO, and clusterin. Baicalin treatment also suppressed neuroinflammation, remodeled the gut microbial composition back to normal, and improved cognition, memory, LTP, cerebral FC, and hippocampal neuronal plasticity. The neuroprotective effects of baicalin were diminished when mice undergoing repeated cerebral ischemia-reperfusion were pretreated with broad-spectrum antibiotics to deplete gut microbial populations. This suggests the neuroprotective effects of baicalin in cerebral ischemia-reperfusion injury are mediated by the gut microbiota. It thus appears that baicalin ameliorates neuropathology in a repeated cerebral ischemia-reperfusion model mice by remodeling the gut microbiota.

Mu-Xiang-You-Fang protects PC12 cells against OGD/R-induced autophagy via the AMPK/mTOR signaling pathway

Ethnopharmacological relevanceMu-Xiang-You-Fang (MXYF) is a classic prescription of Hui medicine. It is composed of five herbs and has been used to treat ischemic stroke for many years. However, the potential pharmacological mechanisms of MXYF remain unclear. The present research is aimed to investigate the protective effect and possible mechanisms of MXYF treatment in an in vitro model of cerebral ischemia-reperfusion injury. Materials and methodsAn oxygen-glucose deprivation and reperfusion (OGD/R) model of PC12 cells was established. The effect of MXYF on the cell viability after OGD/R injury was determined using a cell counting kit (CCK-8) assay. The colorimetric method was used to determine the lactate dehydrogenase (LDH) leakage rate. The calcium concentration was determined by the chemical fluorescence method, and mitochondrial membrane potential was determined using flow cytometry. Monodansylcadaverine (MDC) staining and electron microscopic analysis were then conducted to detect autophagy after oxygen-glucose deprivation and reperfusion in PC12 cells. Immunofluorescence and western blot analyses were used to detect the expression of proteins associated with autophagy. ResultsIt was found that MXYF (1, 2, 4 μg/mL) could significantly increase cell viability and mitochondrial membrane potential and decrease the calcium concentration and LDH release rate in PC12 cells. After OGD/R injury in PC12 cells, the number of autophagosomes and autophagolysosome significantly increased. MXYF (4 μg/mL) inhibited the autophagy induced by OGD/R and inhibited the expression of LC3, beclin1, p-AMPK, and ULK1. In contrast, the expression of p-mTOR, p-p70s6k, and p62 was significantly enhanced. ConclusionsThese findings suggest that MXYF inhibits autophagy after OGD/R-induced PC12 cell injury through the AMPK-mTOR pathway. Thus, MXYF might have therapeutic potential in treating ischemic stroke.

Inhibition of MiR-122 Decreases Cerebral Ischemia-reperfusion Injury by Upregulating DJ-1-Phosphatase and Tensin Homologue Deleted on Chromosome 10 (PTEN)/Phosphonosinol-3 Kinase (PI3K)/AKT.

BackgroundIschemia-reperfusion injury is caused by a blood reperfusion injury in ischemic brain tissue, and usually occurs in the treatment stage of ischemic disease, which can aggravate brain tissue injury. MiR-122 is closely related to ischemia-reperfusion injury in the myocardium, kidney, and liver; however, the role in cerebral ischemia-reperfusion injury has not been established.Material/MethodsIn this study, cerebral ischemia-reperfusion injury was established in a rat model, and the control group was a sham-operated group. After ischemia-reperfusion injury for 6, 12, and 24 hours, brain tissue specimens were collected and the expression of miR-122 and DJ-1 were determined using quantitative real-time polymerase chain reaction. Flow cytometry was used to determine the reactive oxygen species (ROS) content. The modified Neurological Severity Score (mNSS) scale was used to evaluate the sensory and motor function defects of the rats. The malondialdehyde (MDA), superoxide dismutase (SOD), and enzyme activity were determined. The rats in the cerebral ischemia-reperfusion injury model were divided into 2 groups (antagomir-NC group and antagomir miR-122 group). Brain neuron RN-c cells were divided into the following 4 groups: antagomir-NC, antagomir miR-122, pIRES2-blank, and pIRES2-DJ-1. Seventy-two hours after transfection, ischemia-reperfusion treatment was carried out and conventional cultured RN-c cells were used as the control group. Flow cytometry was used to detect apoptosis and western blot was used to detect the expression of DJ-1, PTEN, AKT, and p-AKT.ResultsThe expression of miR-122 increased significantly in the process of ischemia-reperfusion damage after cerebral infarction, while the expression of DJ-1 decreased significantly. Downregulation of miR-122 significantly increased the expression of DJ-1, enhanced the activity of the PTEN/PI3K/AKT pathway, reduced cell apoptosis, and alleviated cerebral ischemia-reperfusion injury.ConclusionsInhibition of miR-122 can decrease cerebral ischemia-reperfusion injury by upregulating DJ-1-PTEN/PI3K/AKT pathway.

Asiaticoside Alleviates Cerebral Ischemia-Reperfusion Injury via NOD2/Mitogen-Activated Protein Kinase (MAPK)/Nuclear Factor kappa B (NF-κB) Signaling Pathway.

BackgroundCerebral ischemia-reperfusion injury (CIRI) remains a serious health problem. Centella asiatica formulations are used to treat central nervous system disorders. In the present study, asiaticoside, an extract of the plant Centella asiatica, was investigated in CIRI in vivo and vitro.Material/MethodsWe made a CIRI model in vivo in SD rats treated by middle cerebral artery occlusion, and a cell model of ischemia-reperfusion injury was made in PC12 cells treated by deprivation of oxygen and glucose/restoration. CIRI in vivo was assessed by scores of neurological functions, encephaledema, and cerebral infarction area. Inflammation level and oxidative stress level were detected by the appropriate kits. TUNEL assay was performed for assessment of cell apoptosis and Western blot analysis was performed to assess protein expression levels. CCK8 assay was performed for evaluation of cell survival and flow cytometer was used to detect cell apoptosis in vitro.ResultsNervous function injury, brain edema, cell apoptosis, infarct size, apoptosis-related protein expressions, and protein expressions of the NOD2/MAPK/NF-κB signaling pathway in the CIRI model were all reversed by asiaticoside in rats. The cell apoptosis, inflammation level, and oxidative stress level in the model of cerebral ischemia-reperfusion injury were reduced by asiaticoside. The effects of asiaticoside on CIRI were reversed by NOD 2 agonists.ConclusionsAsiaticoside showed a protective effect against cerebral ischemia-reperfusion injury via the NOD2/MAPK/NF-κB signaling pathway. These findings are vital for future research on use of asiaticoside in CIRI, providing a new avenue for alleviating CIRI.

The Effects of Electroacupuncture in a Rat Model of Cerebral Ischemia-Reperfusion Injury Following Middle Cerebral Artery Occlusion Involves MicroRNA-223 and the PTEN Signaling Pathway.

BackgroundIn China, electroacupuncture (EA) is used to treat the symptoms of ischemic stroke. However, the mechanisms involved in the effects of EA in cerebral ischemia remain to be investigated. This study aimed to investigate the molecular mechanism underlying the effects of EA in a rat model of cerebral ischemia-reperfusion injury (CIRI) induced by middle cerebral artery occlusion (MCAO).Material/MethodsSeventy-five male Sprague-Dawley rats were divided into five groups: the sham group (with sham surgery), the model group (the MCAO model), the EA group (treated with EA), the EA control group, and the EA+antagomir-223-3p group. Rats in the model of CIRI underwent MCAO for 90 minutes. EA was performed on the second postoperative day and was performed at the Waiguan (TE5) and Zusanli (ST36) acupoints. The rat brains were evaluated for structural and molecular markers.ResultsEA treatment significantly upregulated the expression of microRNA-223 (miR-223), NESTIN, and NOTCH1, and downregulated the expression of PTEN in the subventricular zone (SVZ) and hippocampus. The luciferase reporter assay supported that PTEN was a direct target of miR-223, and antagomiR-223-3p reversed the effects of EA and reduced the increase in NESTIN and inhibition of PTEN expression associated with EA treatment. There was a negative correlation between PTEN expression and the number of neural stem cells (NSCs).ConclusionsIn a rat model of CIRI following MCAO, EA activated the NOTCH pathway, promoted the expression of miR-223, increased the number of NSCs, and reduced the expression of PTEN.

Electroacupuncture pretreatment alleviated cerebral ischemia-reperfusion injury via suppressing autophagy in cerebral cortex tissue in rats

To investigate the effect of electroacupuncture (EA) preconditioning on autophagy in cerebral cortex tissues of rats with cerebral ischemia-reperfusion injury (CIRI), so as to explore its mechanisms underlying improvement of CIRI. Thirty-three male Sprague-Dawley rats were randomly divided into sham operation, model and EA groups (n=11 in each group). EA (2 Hz/15 Hz, 1 mA) was applied to "Baihui"(GV20), "Quchi" (LI11) and "Zusanli" (ST36) for 30 min, once daily for 5 days, followed by establishment of CIRI model by occlusion of the middle cerebral artery (MCAO) for 1.5 h and reperfusion for 24 h. The neurological deficit score was assessed in reference to Longa's methods, and the infarct volume assessed by 2,3,5-triphenyltetrazolium chloride staining. The density of dendrite spines of neurons in the ischemic cerebral cortex tissue was detected by Golgi's staining, the autophagosome observed by electron microscopy, and the expression levels of microtubule-associated protein 1 light chain 3 (LC3) and p62 (a selective autophagy substrate) were detected by Western blot. Compared with the sham operation group, the neurological deficit score and infarct volume were significantly increased (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ also significantly increased (P<0.01), while the expression level of p62 was notably decreased in the model group (P<0.01). Following the intervention and in comparison with the model group, the neurological deficit score and infarct volume were significantly reduced (P<0.01), the number of autophagosomes and the ratio of LC3-Ⅱ/LC3-Ⅰ obviously decreased (P<0.01), and the expression of p62 was significantly up-regulated in the EA group (P<0.01). EA pretreatment is effective in improving CIRI in rats, which may be realized through suppressing autophagy in the ischemic cerebral cortex tissue.

Iridoid glycosides from Radix Scrophulariae attenuates focal cerebral ischemia‑reperfusion injury via inhibiting endoplasmic reticulum stress‑mediated neuronal apoptosis in rats.

Iridoid glycosides of Radix Scrophulariae (IGRS) are a group of the major bioactive components from Radix Scrophulariae with extensive pharmacological activities. The present study investigated the effects of IGRS on cerebral ischemia-reperfusion injury (CIRI) and explored its potential mechanisms of action. A CIRI model in rats was established by occlusion of the right middle cerebral artery for 90 min, followed by 24 h of reperfusion. Prior to surgery, 30, 60 or 120 mg/kg IGRS was administered to the rats once a day for 7 days. Then, the neurological scores, brain edema and volume of the cerebral infarction were measured. The apoptosis index was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling. The effects of IGRS on the histopathology of the cortex in brain tissues and the endoplasmic reticulum ultrastructure in the hippocampus were analyzed. Finally, the expression of endoplasmic reticulum stress (ERS)-regulating mediators, endoplasmic reticulum chaperone BiP (GRP78), DNA damage-inducible transcript 3 protein (CHOP) and caspase-12, were detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The volume of cerebral infarction and brain water content in the IGRS-treated groups treated at doses of 60 and 120 mg/kg were decreased significantly compared with the Model group. The neurological scores were also significantly decreased in the IGRS-treated groups. IGRS treatment effectively decreased neuronal apoptosis resulting from CIRI-induced neuron injury. In addition, the histopathological damage and the endoplasmic reticulum ultrastructure injury were partially improved in CIRI rats following IGRS treatment. RT-qPCR and western blot analysis data indicated that IGRS significantly decreased the expression levels of GRP78, CHOP and caspase-12 at both mRNA and protein levels. The results of the present study demonstrated that IGRS exerted a protective effect against CIRI in brain tissue via the inhibition of apoptosis and ERS.

Dexmedetomidine inhibits neuronal apoptosis by inducing Sigma-1 receptor signaling in cerebral ischemia-reperfusion injury.

Dexmedetomidine is known to alleviate cerebral ischemia-reperfusion injury (CIRI). We established a rat model of CIRI, which exhibited higher neurological deficit scores and a greater number of apoptotic cells in the cerebral ischemic penumbra than controls. Dexmedetomidine reversed the neuronal apoptosis and improved neurological function in this model. We then examined Sigma-1 receptor (Sig-1R) expression on the endoplasmic reticulum (ER) in brain tissues at different reperfusion time points. Sig-1R expression increased with CIRI and decreased with increasing reperfusion times. After 24 hours of reperfusion, dexmedetomidine upregulated Sig-1R expression, and ER stress proteins (GRP78, CHOP, JNK and Caspase-3) were detected in brain tissues with Western blotting. Moreover, GRP78 expression followed a pattern similar to Sig-1R. Dexmedetomidine induced GRP78 expression but inhibited CHOP, Caspase-3 and phosphorylated-JNK expression in brain tissues. A Sig-1R-specific inhibitor reduced GRP78 expression and partially inhibited the upregulation of GRP78 by dexmedetomidine. The inhibitor also increased CHOP and Caspase-3 expression and partially reversed the inhibitory effects of dexmedetomidine on these pro-apoptotic ER stress proteins. These results suggest that dexmedetomidine at least partially inhibits ER stress-induced apoptosis by activating Sig-1R, thereby attenuating brain damage after 24 hours of ischemia-reperfusion.

Effect of P-Hydroxycinnamic Acid in Mice Model of Cerebral Ischemia-Reperfusion Injury

Multiple pathomechanisms of cerebral ischemia reperfusion (I/R) injuries can be ameliorated by certain high-potential pharmaceutical substances. In the present study, we investigated the acute effect of p-hydroxycinnamic (pHCA) acid against cerebral I/R injury in mice. Thirty male ICR mice were divided into Sham, Control-I/R, and pHCA-I/R groups. The pHCA 100 mg/kg and the vehicle were given 30 min before I/R induction. Thirty-minute bilateral common carotid artery occlusion followed by 45-min reperfusion was performed on the Control-I/R and pHCA-I/R groups. Brains were collected for biochemical analysis, infarction and histological study of the cerebral cortex and corpus callosum (CC). The results showed that I/R induction significantly induced biochemical changes (p<0.05) along with the increase of brain infarction (p<0.05), percentage of degeneration in cerebral cortex (p<0.05) and decrease of CC white matter density (p<0.05). Pretreatment with pHCA significantly reduced MDA (p<0.05), brain infarction (p<0.05), cerebral cortex neuronal degeneration (p<0.05) and prevented the reduction of white matter density in the CC (p<0.05). The present study concluded that pretreatment with pHCA helps prevent cerebral I/R injury by amelioration of lipid peroxidation, white matter damage and neuronal degeneration.

Remote ischemic conditioning for acute moderate ischemic stroke (RICAMIS): Rationale and design.

A large number of basic and clinical studies have proved that remote ischemic conditioning has neuroprotective effect. For example, remote ischemic conditioning showed a neuroprotective role in cerebral ischemia-reperfusion injury model. Recent clinical studies suggested that remote ischemic conditioning may improve neurological function and reduce the risk of recurrence in ischemic stroke patients. However, there is a lack of convincing evidence for the neuroprotective effect of remote ischemic conditioning on ischemic stroke, which deserves further study. To explore the efficacy and safety of remote ischemic conditioning for acute moderate ischemic stroke. A maximum of 1800 subjects are required to test the superiority hypothesis with 80% power according to a one-sided 0.025 level of significance, stratified by gender, age, time from onset to treatment, National Institutes of Health Stroke Scale (6-10 vs. 11-16), degree of responsible vessel stenosis, location of stenosis, and stroke etiology. Remote Ischemic Conditioning for Acute Moderate Ischemic Stroke is a prospective, random, open label, blinded endpoint and multi-center study. The subjects are divided into experimental group and control group randomly. The experimental group was treated with remote ischemic conditioning twice daily with 200 mmHg pressure for 10-14 days besides guideline-based therapy. The control group was treated according to the guidelines. The primary efficacy endpoint is favorable functional outcome, defined as modified Rankin Scale 0-1 at 90 days post-randomization.