Cerebral Artery Occlusion In Rats Research Articles

The negative ultraslow potential, electrophysiological correlate of infarction in the human cortex.

Spreading depolarizations are characterized by abrupt, near-complete breakdown of the transmembrane ion gradients, neuronal oedema, mitochondrial depolarization, glutamate excitotoxicity and activity loss (depression). Spreading depolarization induces either transient hyperperfusion in normal tissue; or hypoperfusion (inverse coupling = spreading ischaemia) in tissue at risk for progressive injury. The concept of the spreading depolarization continuum is critical since many spreading depolarizations have intermediate characteristics, as opposed to the two extremes of spreading depolarization in either severely ischaemic or normal tissue. In animals, the spreading depolarization extreme in ischaemic tissue is characterized by prolonged depolarization durations, in addition to a slow baseline variation termed the negative ultraslow potential. The negative ultraslow potential is initiated by spreading depolarization and similar to the negative direct current (DC) shift of prolonged spreading depolarization, but specifically refers to a negative potential component during progressive recruitment of neurons into cell death in the wake of spreading depolarization. We here first quantified the spreading depolarization-initiated negative ultraslow potential in the electrocorticographic DC range and the activity depression in the alternate current range after middle cerebral artery occlusion in rats. Relevance of these variables to the injury was supported by significant correlations with the cortical infarct volume and neurological outcome after 72 h of survival. We then identified negative ultraslow potential-containing clusters of spreading depolarizations in 11 patients with aneurysmal subarachnoid haemorrhage. The human platinum/iridium-recorded negative ultraslow potential showed a tent-like shape. Its amplitude of 45.0 (39.0, 69.4) mV [median (first, third quartile)] was 6.6 times larger and its duration of 3.7 (3.3, 5.3) h was 34.9 times longer than the negative DC shift of spreading depolarizations in less compromised tissue. Using Generalized Estimating Equations applied to a logistic regression model, we found that negative ultraslow potential displaying electrodes were significantly more likely to overlie a developing ischaemic lesion (90.0%, 27/30) than those not displaying a negative ultraslow potential (0.0%, 0/20) (P = 0.004). Based on serial neuroimages, the lesions under the electrodes developed within a time window of 72 (56, 134) h. The negative ultraslow potential occurred in this time window in 9/10 patients. It was often preceded by a spreading depolarization cluster with increasingly persistent spreading depressions and progressively prolonged DC shifts and spreading ischaemias. During the negative ultraslow potential, spreading ischaemia lasted for 40.0 (28.0, 76.5) min, cerebral blood flow fell from 57 (53, 65) % to 26 (16, 42) % (n = 4) and tissue partial pressure of oxygen from 12.5 (9.2, 15.2) to 3.3 (2.4, 7.4) mmHg (n = 5). Our data suggest that the negative ultraslow potential is the electrophysiological correlate of infarction in human cerebral cortex and a neuromonitoring-detected medical emergency.awy102media15775596049001.

Hypoxia Inducible Factor 1α Plays a Key Role in Remote Ischemic Preconditioning Against Stroke by Modulating Inflammatory Responses in Rats.

BackgroundLimb remote ischemic preconditioning (RIPC) protects against brain injury induced by stroke, but the underlying protective mechanisms remain unknown. As hypoxia inducible factor 1α (HIF‐1α) is neuroprotective in stroke and mediates neuroinflammation, we tested the hypothesis that HIF‐1α is a key factor of RIPC against stroke by mediating inflammation.Methods and ResultsStroke was induced by transient middle cerebral artery occlusion in rats, and RIPC was conducted in both hind limbs. The HIF‐1α mRNA was examined by quantitative reverse transcription polymerase chain reaction after RIPC. In addition, inflammatory cytokines in the peripheral blood and brain were measured using the AimPlex multiplex immunoassays. Data showed that RIPC reduced the infarct size, improved neurological functions, and increased HIF‐1α mRNA levels, interleukin (IL)‐4, and IL‐10 protein levels in the peripheral blood. Intraperitoneal injection of the HIF activator, dimethyloxaloylglycine, reduced the infarct size and inhibited interferon‐γ protein levels, while promoting IL‐4 and IL‐10 protein levels, while decreasing interferon‐γ protein levels in both the peripheral blood and ischemic brain. In addition, injection of dimethyloxaloylglycine had a synergistic effect with RIPC on reducing infarction and improving neurological functions, as well as decreasing interferon‐γ in the peripheral blood and ischemic brain. In contrast, injection of the HIF inhibitor, acriflavine hydrochloride, abolished the protective effects of RIPC on infarction, and reduced IL‐4 and IL‐10 protein levels in both the peripheral blood and ischemic brain.ConclusionsWe conclude that HIF‐1α plays a key role in RIPC, likely mediated by a systemic modulation of the inflammatory response.

MicroRNA-149-5p regulates blood-brain barrier permeability after transient middle cerebral artery occlusion in rats by targeting S1PR2 of pericytes.

Blood-brain barrier (BBB) disruption caused by reperfusion injury after ischemic stroke is an intractable event conducive to further injury. Brain pericytes play a vital role in maintaining BBB integrity by interacting with other components of the BBB. In this study, we found that sphingosine-1-phosphate receptor (S1PR)2 expressed in pericytes was significantly up-regulated after ischemia in vivo and in vitro. By using a S1PR2 antagonist (JTE-013), we showed that S1PR2 plays a critical role in the induction of BBB permeability of transient middle cerebral artery occlusion (tMCAO) rats and the in vitro BBB model. Furthermore, we discovered that S1PR2 may decrease N-cadherin expression and increase pericyte migration via NF-κB p65 signal and found that S1PR2 could be regulated by miR-149-5p negatively, which was decreased in the ischemic boundary zone and cultured pericytes after ischemia. Overexpression of miR-149-5p in cultured pericytes substantially increased N-cadherin expression and decreased pericyte migration, which decreased BBB leakage in the in vitro model. Up-regulating miR-149-5p by intracerebroventricular injection of agomir-149-5p attenuated BBB permeability and improved the outcomes of tMCAO rats significantly. Thus, our data suggest that miR-149-5p may serve as a potential target for treatment of BBB disruption after ischemic stroke.-Wan, Y., Jin, H.-J., Zhu, Y.-Y., Fang, Z., Mao, L., He, Q., Xia, Y.-P., Li, M., Li, Y., Chen, X., Hu, B. MicroRNA-149-5p regulates blood-brain barrier permeability after transient middle cerebral artery occlusion in rats by targeting S1PR2 of pericytes.

Protective Effect of Klotho against Ischemic Brain Injury Is Associated with Inhibition of RIG-I/NF-κB Signaling.

Aging is the greatest independent risk factor for the occurrence of stroke and poor outcomes, at least partially through progressive increases in oxidative stress and inflammation with advanced age. Klotho is an antiaging gene, the expression of which declines with age. Klotho may protect against neuronal oxidative damage that is induced by glutamate. The present study investigated the effects of Klotho overexpression and knockdown by an intracerebroventricular injection of a lentiviral vector that encoded murine Klotho (LV-KL) or rat Klotho short-hairpin RNA (LV-KL shRNA) on cerebral ischemia injury and the underlying anti-neuroinflammatory mechanism. The overexpression of Klotho induced by LV-KL significantly improved neurobehavioral deficits and increased the number of live neurons in the hippocampal CA1 and caudate putamen subregions 72 h after cerebral hypoperfusion that was induced by transient bilateral common carotid artery occlusion (2VO) in mice. The overexpression of Klotho significantly decreased the immunoreactivity of glial fibrillary acidic protein and ionized calcium binding adaptor molecule-1, the expression of retinoic-acid-inducible gene-I, the nuclear translocation of nuclear factor-κB, and the production of proinflammatory cytokines (tumor necrosis factor α and interleukin-6) in 2VO mice. The knockdown of Klotho mediated by LV-KL shRNA in the brain exacerbated neurological dysfunction and cerebral infarct after 22 h of reperfusion following 2 h middle cerebral artery occlusion in rats. These findings suggest that Klotho itself or enhancers of Klotho may compensate for its aging-related decline, thus providing a promising therapeutic approach for acute ischemic stroke during advanced age.

Detrimental effects of 2-arachidonoylglycerol on whole blood platelet aggregation and on cerebral blood flow after a focal ischemic insult in rats.

2-Arachidonoylglycerol (2-AG) is a major modulator of blood flow and platelet aggregation and a potential neuroprotectant. The present study investigated, for the first time, the effects of 2-AG on cerebral blood flow (CBF) in the first critical hours during middle cerebral artery occlusion (MCAO) and on platelet aggregation in rats. Adult male Sprague-Dawley rats ( n = 30) underwent permanent MCAO under isoflurane anesthesia and were randomly assigned to receive either 2-AG (6 mg/kg iv), monoacylglycerol lipase inhibitor JZL-184 (10 mg/kg iv), or vehicle ( n = 6 rats/group) treatment. CBF and cardiovascular responses were measured, by a blinded investigator, for up to 4 h. In separate experiments, platelet aggregation by 2-AG (19-300 µM) was assessed by whole blood aggregometry ( n = 40). 2-AG and JZL-184 significantly increased the severity of the CBF deficit versus vehicle (20.2 ± 8.8% and 22.7 ± 6.4% vs. 56.4 ± 12.1% of pre-MCAO baseline, respectively, P < 0.05) but had no effect on blood pressure or heart rate. While JZL-184 significantly increased the number of thrombi after MCAO, this did not reach significance by 2-AG. 2-AG induced platelet aggregation in rat whole blood in a similar manner to arachidonic acid and was significantly reduced by the cyclooxygenase inhibitors indomethacin and flurbiprofen and the thromboxane receptor antagonist ICI 192,605 ( P < 0.05). This is the first study showing that 2-AG increases the severity of the CBF deficit during MCAO, and further interrogation confirmed 2-AG-induced platelet aggregation in rats. These findings are important because 2-AG had previously been shown to exert neuroprotective actions and therefore force us to reevaluate the circumstances under which 2-AG is beneficial. NEW & NOTEWORTHY 2-Arachidonoylglycerol (2-AG) has neuroprotective properties; however, the present study revealed that 2-AG increases the severity of the cerebral blood flow deficit during middle cerebral artery occlusion in rats. Further interrogation showed that 2-AG induces platelet aggregation in rats. These findings force us to reevaluate the circumstances under which 2-AG is beneficial.

MRI Guiding of the Middle Cerebral Artery Occlusion in Rats Aimed to Improve Stroke Modeling

The middle cerebral artery occlusion (MCAO) model in rats closely imitates ischemic stroke and is widely used. Existing instrumental methods provide a certain level of MCAO guidance, but monitoring of the MCA-occluding intraluminal filament position and possible complications can be improved. The goal of this study was to develop a MRI-based method of simultaneous control of the filament position, blood flow in the intracranial vessels, and hemorrhagic complications. Rats were subjected to either MRI-guided MCAO (group 1, n = 51) or MCAO without MRI control (group 2, n = 38). After operation, group 1 rats were transferred into a MRI scanner for the control of the filament position and possible complications. Ninety minutes after the onset of MCAO, the filament was removed in rats of both groups and MRI control of the infarct volume and hemorrhagic complications performed. High-resolution T1- and T2-weighted imaging performed immediately after filament insertion provided visualization of the filament position, blood flow in brain arteries, and complications related to inappropriate filament insertion. It permitted replacement of wrongly positioned filaments and exclusion of animals with complications from the experiment. MRI-based MCAO guiding provided real-time intra-operational monitoring of crucial parameters determining MCAO suitability for stroke modeling, including better assessment of the operation outcomes in individual animals and significant enhancement of the model success rate. The possibility of simultaneous visualization of the filament, blood flow in the arteries, brain tissue, and hemorrhagic complications is the principal advantage of the proposed method over other instrumental methods of MCAO quality control.Graphical MRI-guided middle cerebral artery occlusion technique permits intra-operational monitoring via direct non-invasive simultaneous visualization of the filament, blood flow in the arteries, brain tissue, and hemorrhagic complications. It provides better assessment of MCAO outcomes in individual animals and significant enhancement of MCAO success rate.

Protective effects of beef decoction rich in carnosine on cerebral ischemia injury by permanent middle cerebral artery occlusion in rats.

Inflammation has a role in the cerebral injury induced by ischemia and the present study aimed to determine the mechanism of the protective effect of beef decoction (BD) with carnosine against it. A rat model of permanent middle cerebral artery occlusion was established using a suture method in the vehicle and each of the BD groups. In experiment 1, 72 Sprague Dawley (SD) rats were randomly divided into three groups: Sham, vehicle and BD-treated group. Rats in the BD group were given 600 mg/kg BD by oral gavage for 1, 3 and 7 days. The sham and vehicle group rats received an equivalent amount of normal saline. In experiment 2, 60 SD rats were randomly divided into six groups: Sham-operated I, sham-operated II, vehicle, low-dose BD, medium-dose BD and high-dose BD group. Rats in the low-, medium- and high-dose BD groups were given BD at the dose of 200, 400 and 600 mg/kg, respectively, by oral gavage for 7 days. Rats in the sham-operated II group were given 600 mg/kg BD. Rats in the sham-operated I group and vehicle group were given the same volume of normal saline by oral gavage. The body weight, neurological deficits and infarct volume were recorded at 1, 3 and 7 days after the operation. Furthermore, the effect of different doses of BD on interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin-4 (IL-4) levels in peripheral blood was measured at 7 days. BD-treated rats showed less neurological deficits and a smaller infarct volume at 7 days. BD at 400 and 600 mg/kg significantly decreased the infarct volume in rats. At 600 mg/kg BD, a decline in IL-6, TNF-α, IFN-γ and an increase in IL-4 expression was observed in the BD groups, while no difference in body weight and neurological dysfunction was detected. In conclusion, BD is a neuroprotective agent that may be used as a supplement treatment of ischemic stroke.

Repulsive guidance molecule a suppresses angiogenesis after ischemia/reperfusion injury of middle cerebral artery occlusion in rats.

Repulsive guidance molecule a (RGMa) has now emerged as a molecule with pleiotropic roles, including repulsion, adhesion, migration and differentiation in the nervous system. In this study, adult male Sprague-Dawley (SD) rats received 90-min middle cerebral artery occlusion (MCAO) to observe RGMa/neogenin expression sites after ischemia/reperfusion injury and changes in angiogenesis after treatment with RNA interference using RGMa-specific recombinant adenovirus rAd5-shRNA-RGMa (rAd-shRGMa). To clarify how RGMa mediates angiogenesis, the RGMa function-blocking peptide six fibronectin type III (6FNIII) was also administered, and corresponding changes in vascular endothelial growth factor (VEGF), angiopoietin-2 (Ang2), angiopoietin-1 (Ang1), and brain derived neurotrophic factor (BDNF) were determined by western blotting. Both RGMa and its receptor neogenin were expressed in neurons and vessel endothelial cells after ischemia/reperfusion injury, and angiogenesis, coupled with functional recovery, was enhanced after RNA interference against RGMa compared with the vehicle groups. VEGF, Ang2, Ang1 and BDNF expression levels were significantly increased after intervention with rAd-shRGMa or 6FNIII. Thus, RGMa might suppress angiogenesis via VEGF, Ang2, Ang1 and BDNF after cerebral ischemia/reperfusion injury, which has therapeutic potential by reducing these endogenous detrimental mechanisms.

Effect of electroacupuncture on expressions of VEGF and CD31 in MCAO model rats

To investigate the effect of electroacupuncture (EA) at Ganshu (BL 18) and Shenshu (BL 23) on vascular endothelial growth factor (VEGF) and platelet endothelial cell adhesion molecule-1 (PECAM-1)/CD31 around the cerebral infarction focus in middle cerebral artery occlusion (MCAO) rats and the possible mechanism, thus to provide a new strategy for the treatment of cerebral ischemic stroke by acupuncture. A total of 180 healthy male Sprague-Dawley (SD) rats were randomly divided into a sham operation group, a model group, an acupoint group and a non-acupoint group, 45 rats in each group. MCAO model was established using the modified line-embolus method in all rats except for those in the sham operation group; rats in the acupoint group were treated with EA at Ganshu (BL 18) and Shenshu (BL 23); rats in the non-acupoint group were treated with EA at the control points; rats in other 2 groups were only subjected to bundling without treatment. Ten rats in each group were randomly selected on the 3rd day, the 14th day and the 21st day after acupuncture stimulation to test the neurological function impairment. The expression levels of CD31 and VEGF were also detected. Compared with the model group and non-acupoint group, the neurological function score of the acupoint group was decreased at each time point, and the differences were statistically significant (P<0.05, P<0.01). The expressions of VEGF and CD31 in each group were the lowest on the 3rd day, reached the peak on the 14th day and still remained at high level on the 21st day. And the differences among groups were statistically significant both on the 14th day and the 21st day (P<0.05, P<0.01). Compared with the model group and the non-acupoint group, the expressions of VEGF and CD31 in the acupoint group were increased, and the differences were statistically significant (all P<0.05). EA at Ganshu (BL 18) and Shenshu (BL 23) can significantly improve the neurological function score of MCAO model rats, and shows protective effect on cerebral ischemia. The protective mechanism may be related to the up-regulation of CD31 and VEGF expression around the cerebral infarction focus in the MCAO model rats and induction of angiogenesis.

TRPV1 receptor-mediated expression of Toll-like receptors 2 and 4 following permanent middle cerebral artery occlusion in rats.

Objective(s):Stroke is known as a main cause of mortality and prolonged disability in adults. Both transient receptor potential V1 (TRPV1) channels and toll-like receptors (TLRs) are involved in mediating the inflammatory responses. In the present study, the effects of TRPV1 receptor activation and blockade on stroke outcome and gene expression of TLR2 and TLR4 were assessed following permanent middle cerebral artery occlusion in ratsMaterials and Methods:Eighty male Wistar rats were divided into four groups as follows: sham, vehicle, AMG9810 (TRPV1 antagonist) -treated and capsaicin (TRPV1 agonist) -treated. For Stroke induction, the middle cerebral artery was permanently occluded and then behavioral functions were evaluated 1, 3 and 7 days after stroke.Results:TRPV1 antagonism significantly reduced the infarct volume compared to the stroke group. Also, neurological deficits were decreased by AMG9810 seven days after cerebral ischemia. In the ledged beam-walking test, the slip ratio was enhanced following ischemia. AMG9810 decreased this index in stroke animals. However, capsaicin improved the ratio 3 and 7 days after cerebral ischemia. Compared to the sham group, the mRNA expression of TLR2 and TLR4 was significantly increased in the stroke rats. AMG9810 Administration significantly reduced the mRNA expression of TLR2 and TLR4. However, capsaicin did not significantly affect the gene expression of TLR2 and TLR4.Conclusion:Our results demonstrated that TRPV1 antagonism by AMG9810 attenuates behavioral function and mRNA expression of TLR2 and TLR4. Thus, it might be useful to shed light on future therapeutic strategies for the treatment of ischemic stroke.

Effects of co-administration of bone marrow stromal cells and green tea antioxidant on infarction volume and neurologic disorders after permanent middle cerebral artery occlusion in rat

Effects of co-administration of bone marrow stromal cells and green tea antioxidant on infarction volume and neurologic disorders after permanent middle cerebral artery occlusion in rat

Neuroprotective effect of Naomaitong extract following focal cerebral ischemia induced by middle cerebral artery occlusion in rats

ObjectiveTo examine the neuroprotective effect of extract from Naomaitong following focal cerebral ischemia reperfusion induced by occlusion of middle cerebral artery (MCA), and to determine the biochemical alterations in urine using proton nuclear magnetic resonance spectroscopy and principal component analysis. MethodsWistar rats were randomly assigned to three groups: sham-operated group, MCA focal cerebral ischemia reperfusion model group, and active extract of Naomaitong treatment group. The model was established by an improved MCA occlusion (MCAO) method. Sham-operated rats received the same surgical procedure, but without occlusion. The Naomaitong treatment group were treated with active extract from Naomaitong at a dose of 3.0 g·kg−1·d−1. Brain tissues and urine samples were collected from all groups for histopathological assessment and proton nuclear magnetic resonance spectroscopy-based metabonomics, respectively. ResultsHematoxylin-eosin and triphenyl tetrazolium chloride staining of brain tissues showed a significant decrease in cerebral infarction area in the Naomaitong group. In model rats, metabonomic analyses showed increased urinary levels of glutamate, taurine, trimetlylamine oxide, betaine, and glycine, and reduced levels of creatinine and creatine. Naomaitong regulated the metabolic changes by acting on multiple metabolic pathways, including glycine metabolism, glutaminolysis, transmethylation metabolism and creatinine metabolism. ConclusionThese data demonstrate that extract from Naomaitong is neuroprotective against focal cerebral ischemia induced by MCAO, and can alleviate biochemical changes in urinary metabolism. Metabonomics may be a useful approach for assessing the biochemical mechanisms underlying the neuroprotective actions of extract from Naomaitong.

Effects of active components group of Xiaoxuming decoction on brain mitochondria in cerebral ischemia/reperfusion rats during early recovery period

To observe the effect of active components group of Xiaoxuming decoction (XXMD) on brain mitochondria in cerebral ischemia/reperfusion rats during early recovery period, and study its protective mechanism for nerves in cerebral ischemia/reperfusion rats during early recovery period. Cerebral ischemia model of middle cerebral artery occlusion in rats was established by suture method, and reperfusion was conducted 2 h later. The degree of cerebral ischemia in rats was evaluated by using Zea-Longa's standard grading method, and the model rats were randomly divided into model group, Xiaoxuming decoction active components low, medium and high dose groups and positive drug Ginaton group, with sham operated rats as control group. Gradient centrifugation was used to extract the mitochondria from rat brain after 5 days of drug administration. Then the mitochondrial respiratory function was measured by Clark oxygen electrode method; mitochondrial membrane potential and the mitochondrial reactive oxygen species(ROS) level were detected by fluorescence probe methods; and the activity of mitochondrial succinodehydrogenase (SDH) and the content of ATP in the ischemic region of MCAO rats were measured by spectrophotometric method. The results showed that as compared with the model group, XXMD could significantly improve mitochondrial respiratory activity, increase the activity of SDH, reduce the level of ROS, increase mitochondrial membrane potential and obviously promote the synthesis of ATP in brain tissues. The results indicated that XXMD active components group could alleviate the energy metabolism disorders, protect brain mitochondrial damage and improve mitochondrial function in MCAO rats, which may be the mechanism of its neuroprotection activity.

Assessment of the Neuroprotective Effects of Arginine-Rich Protamine Peptides, Poly-Arginine Peptides (R12-Cyclic, R22) and Arginine-Tryptophan-Containing Peptides Following In Vitro Excitotoxicity and/or Permanent Middle Cerebral Artery Occlusion in Rats.

We have demonstrated that arginine-rich and poly-arginine peptides possess potent neuroprotective properties with arginine content and peptide positive charge being particularly critical for neuroprotective efficacy. In addition, the presence of other amino acids within arginine-rich peptides, as well as chemical modifications, peptide length and cell-penetrating properties also influence the level of neuroprotection. Against this background, we have examined the neuroprotective efficacy of arginine-rich protamine peptides, a cyclic (R12-c) poly-arginine peptide and a R22 poly-arginine peptide, as well as arginine peptides containing tryptophan or other amino acids (phenylalanine, tyrosine, glycine or leucine) in in vitro glutamic acid excitotoxicity and in vivo rat permanent middle cerebral artery occlusion models of stroke. In vitro studies demonstrated that protamine and poly-arginine peptides (R12-c, R22) were neuroprotective. Arginine-tryptophan-containing peptides were highly neuroprotective, with R12W8a being the most potent arginine-rich peptide identified in our laboratory. Peptides containing phenylalanine or tyrosine substituted in place of tryptophan in R12W8a were also highly neuroprotective, whereas leucine, and in particular glycine substitutions, decreased peptide efficacy. In vivo studies with protamine administered intravenously at 1000nmol/kg 30min after MCAO significantly reduced infarct volume and cerebral oedema by 22.5 and 38.6%, respectively. The R12W8a peptide was highly toxic when administered intravenously at 300 or 100nmol/kg and ineffective at reducing infarct volume when administered at 30nmol/kg 30min after MCAO, unlike R18 (30nmol/kg), which significantly reduced infarct volume by 20.4%. However, both R12W8a and R18 significantly reduced cerebral oedema by 19.8 and 42.2%, respectively. Protamine, R12W8a and R18 also reduced neuronal glutamic acid-induced calcium influx. These findings further highlight the neuroprotective properties of arginine-rich peptides and support the view that they represent a new class of neuroprotective agent.

Upregulation and phosphorylation of HspB1/Hsp25 and HspB5/αB-crystallin after transient middle cerebral artery occlusion in rats

Ischemic stroke leads to cellular dysfunction, cell death, and devastating clinical outcomes. The cells of the brain react to such a cellular stress by a stress response with an upregulation of heat shock proteins resulting in activation of endogenous neuroprotective capacities. Several members of the family of small heat shock proteins (HspBs) have been shown to be neuroprotective. However, yet no systematic study examined all HspBs during cerebral ischemia. Here, we performed a comprehensive comparative study comprising all HspBs in an animal model of stroke, i.e., 1h transient middle cerebral artery occlusion followed by 23h of reperfusion. On the mRNA level out of the 11 HspBs investigated, HspB1/Hsp25, HspB3, HspB4/αA-crystallin, HspB5/αB-crystallin, HspB7/cvHsp, and HspB8/Hsp22 were significantly upregulated in the peri-infarct region of the cerebral cortex of infarcted hemispheres. HspB1 and HspB5 reached the highest mRNA levels and were also upregulated at the protein level, suggesting that these HspBs might be functionally most relevant. Interestingly, in the infarcted cortex, both HspB1 and HspB5 were mainly allocated to neurons and to a lesser extent to glial cells. Additionally, both proteins were found to be phosphorylated in response to ischemia. Our data suggest that among all HspBs, HspB1 and HspB5 might be most important in the neuronal stress response to ischemia/reperfusion injury in the brain and might be involved in neuroprotection.

Protective effect and mechanism of scutellarin ethyl ester on focal cerebral ischemia induced by ligation of middle cerebral artery in rats

To observe the protective effect of scutellarin ethyl ester on focal cerebral ischemia injury induced by middle cerebral artery occlusion in rats(MCAOR), and explore its mechanism. Totally 84 male SD rats were randomly divided into seven groups： sham-operated group, model group,positive drug group(niomdipine,12 mg•kg⁻¹), Brevisapin tablets group(48 mg•kg⁻¹), and high, middle and low-dose scutellarin ethyl ester groups(100, 50, 25 mg•kg⁻¹). The MCAOR model was prepared by using thread embolism method to observe the neurological function of rats, the area of cerebral infarction was measured with TTC, and the levels of MDA, SOD and NO in serum were detected with semiautomatic biochemistry analyzer.Ox-LDL and TNF-α cell injury models was established by treating HUVECs with 200 mg•L⁻¹ ox-LDL and 100 μg•L⁻¹ TNF-α,and the levels of MDA, SOD, NO, ET, 6-keto-PGF1α,TXB2, IL-1, IL-6, IL-8, ICAM-1 and PECAM-1 in the cell supernatant were determined. The results showed that scutellarin ethyl ester could effectively improve the neurological function of MCAOR rats, and significantly reduce the area of cerebral infarction. Compared with the model group, activities of SOD and NO in serum increased, while content of MDA decreased. In the cell supernatant, activities of SOD, 6-keto-PGF1α and NO increased, content of IL-1, IL-6, IL-8, ICAM-1, PECAM-1, TXB2, ET and MDA decreased, which indicated that scutellarin ethyl ester has a certain protective effect on focal cerebral ischemia injury induced by middle cerebral artery occlusion in rats, and its mechanism may be related to antioxidative stress, improvement of endothelial function and reduction in inflammatory reaction.

Effects of acupuncture on the number of associated protein phosphorylation in brain tissues of MCAO rats based on protein microarray technique

To investigate the effects of acupuncture on the number of associated phosphorylated proteins in brain tissues of middle cerebral artery occlusion (MCAO) rats, based on the protein microarray technique. The MCAO model was prepared according to the modified occlusion method using occlusion lines. Forty healthy Sprague-Dawley (SD) rats were randomly divided into 4 groups using the lottery method: a sham operation group, a model group, a control point group and an acupoint group, with 10 rats in each group. Rats in the sham operation group and the model group only received binding without acupuncture. Rats in the acupoint group received acupuncture at Dazhui (GV 14), Baihui (GV 20) and Shuigou (GV 25); rats in the control point group received acupuncture at non-acupoint control points. The needle was twisted once for 1 min after insertion and another time in the middle of the 30 min needle retaining. Acupuncture was conducted once every 12 h for 6 consecutive times. At the end of the experiment, the neurological impairment score was collected, and cells of the ischemic brain tissues were extracted. The protein phosphorylation of the related signaling was detected using the 720 phosphorylated antibody microarray technique, and the differentially expressed proteins between groups were screened. The neurological impairment scores after 72 h of treatment: compared with the sham operation group, the scores of the model group, the control point group and the acupoint group were significantly increased (P<0.01); compared with the model group, the scores of the acupoint group and the control point group were significantly decreased (P<0.01, P<0.05); the score of the acupoint group was better than that of the control point group (P<0.05). The results of the protein microarray: compared with the sham operation group, 48 proteins showed up-regulated phosphorylation (≥1.5 times) in the model group and the down-regulated was 28; compared with the model group, 35 proteins showed up-regulated phosphorylation in the control point group, and the down-regulated was 24. There were 29 proteins showing up-regulated phosphorylation in the acupoint group and the down-regulated was 51. The numbers of proteins involved in the function and signal transduction pathways were also different. Acupuncture at Dazhui (GV 14), Baihui (GV 20) and Shuigou (GV 25) can effectively repair brain injury. The ischemic injury of brain tissue may be caused by imbalance of a variety of proteins, and acupuncture can promote brain tissue repair by multi-functional and multi-channel regulation of the protein disorders.

Down-regulation of microRNA-142-5p attenuates oxygen-glucose deprivation and reoxygenation-induced neuron injury through up-regulating Nrf2/ARE signaling pathway.

MicroRNAs (miRNAs) play vital roles in regulating neuron survival during cerebral ischemia/reperfusion injury. miR-142-5p is reported to be an important regulator of cellular survival. However, little is known about the role of miR-142-5p in regulating neuron survival during cerebral ischemia/reperfusion injury. In this study, we aimed to investigate the precise function and mechanism of miR-142-5p in the regulation of neuron ischemia/reperfusion injury using a cellular model of oxygen-glucose deprivation and reoxygenation (OGD/R)-induced injury in hippocampal neurons in vitro. We found that miR-142-5p was induced in hippocampal neurons with OGD/R treatment. The inhibition of miR-142-5p attenuated OGD/R-induced cell injury and oxidative stress, whereas the overexpression of miR-142-5p aggravated them. Nuclear factor erythroid 2-related factor 2 (Nrf2) was identified as a target gene of miR-142-5p. Moreover, miR-142-5p regulated Nrf2 expression and downstream signaling. Knockdown of Nrf2 abolished the protective effects of miR-142-5p suppression. In addition, we showed an inverse correlation relationship between miR-142-5p and Nrf2 in an in vivo model of middle cerebral artery occlusion in rats. Taken together, these results suggest that miR-142-5p contributes to OGD/R-induced cell injury and the down-regulation of miR-142-5p attenuates OGD/R-induced neuron injury through promoting Nrf2 expression. Our study provides a novel insight into understanding the molecular pathogenesis of cerebral ischemia/reperfusion injury and indicates a potential therapeutic target for the treatment of cerebral ischemia/reperfusion injury.

Increased Expression Of Toll-Like Receptor 2 Mrna Following Permanent Middle Cerebral Artery Occlusion In Rat: Role Of TRPV1 Receptors

Background: Stroke is a major cause of mortality and long term disability in adults. TRPV1 has a pivotal role in neuroinflammation. Among TLRs, TLR2 significantly participate in induction of inflammation in brain. In this study, the effect of TRPV1 receptor agonist and antagonist on outcome and gene expression of TLR2 in a rat model of permanent middle cerebral artery occlusion (MCAO) was investigated.Methods: Forty male rats were assigned to the following groups: sham, vehicle )stroke), AMG9810 (selective TRPV1 antagonist, 0.5 mg/kg; 3 h after stroke), and capsaicin (1 mg/kg; 3 h after stroke). Stroke was induced by permanent middle cerebral artery occlusion and behavioral functions were assessed 1, 3, and 7 days after stroke. Infarct volume, brain edema and mRNA expression of TLR2 were also evaluated at the end of the study.Results: While stroke animals showed infarctions and behavioral functions, we did not observe any cerebral infarction and behavioral functions in sham-operated animals. AMG9810 decreased neurological deficits 7 days after cerebral ischemia (P&lt;0.01). In the ledged beam-walking test, the slip ratio was increased following ischemia (*P &lt; 0.05). AMG9810 improved this index in animals undergone stroke. However, capsaicin enhanced the slip ratio 3 and 7 days after cerebral ischemia (#P&lt;0.05). TLR2) P&lt;0.05(mRNA expression was elevated in ischemic rats. Conclusion: Our data indicate that pharmacological blockade of TRPV1 by AMG9810 attenuates behavioral function and mRNA expression of TLR2. Therefore, it might be useful as a potential target for the treatment of ischemic stroke.

Effect of electroacupuncture at Ganshu (BL 18) and Shenshu (BL 23) on the expression of EphB2 protein in cortex around cerebral infracted area of rat

To observe the effect of electroacupuncture (EA) on the expression of erythropoie-tin-producing hepatocyte receptor B2 (EphB2) in the cortex around the infracted area of middle cerebral artery occlusion (MCAO) rats at different timing, and to reveal the possible mechanism of acupuncture in the treatment of cerebral ischemia. A total of 180 male Sprague-Dawley (SD) rats were randomly divided into a sham operation group, a model group, an acupoint group and a non-acupoint group, with 45 rats in each group. Rats in each group were further divided into three subgroups: postoperative 3 d, postoperative 14 d and postoperative 21 d groups, with 15 rats in each subgroup. The MCAO model was made by the modified occlusion method. The neurological function score, 2,3,5-triphenyl tetrazolium chloride (TTC) staining, immunohistochemistry assay, immunofluorescence double labeling method and Western blot were used to detect the corresponding indicators. The neurological impairment of rats was most obvious at postoperative 3 d, and then gradually improved with time, which was more significant in the acupoint group (P<0.05). The change of infarcted volume was consistent with the neurological function impairment. The number of EphB2 positive cells (EphB2+) around the infarcted area was decreased significantly at postoperative 3 d, and then gradually improved with time, which returned to the same level as that in the sham operation group at postoperative 21 d. The increase was most significant in the acupoint group (P<0.05), and the positive cell number was higher than that in the sham operation group (P<0.01). Western blot and immunohistochemistry results were basically consistent. Immunofluorescence displayed that EphB2+ and postsynaptic density-95 positive (PSD-95+) were co-expressed, after the MCAO operation, in the cortical neuron around the infracted area, and the number of co-expressing cells was increased gradually with time, which was most significant in the acupoint group (P<0.05). Electroacupuncture at Ganshu (BL 18) and Shenshu (BL 23) can significantly improve the neurological function and cerebral infarcted volume ratio of MCAO rats, which may be related to the activation of EphB2 expression in cortex around the infracted area and the promotion of synaptic remodeling.