Catechin Hydrate Ameliorates Redox Imbalance and Limits Inflammatory Response in Focal Cerebral Ischemia

Epidemiologic studies have shown that foods rich in polyphenols, such as flavonoids, can lower the risk of ischemic disease; however, the mechanism of protection has not been clearly investigated. In this study, we hypothesized that pretreatment effect of catechin hydrate (CH) on functional outcome, neuronal damage and on secondary injuries in the ischemic brain of rats. To test this hypothesis, male Wistar rats were pretreated with CH (20 mg/kg b.wt) for 21 days and then subjected to 2 h middle cerebral artery occlusion (MCAO) followed by 22 h of reperfusion. After 2 h MCAO/22 h reperfusion, neurological deficit, infarct sizes, activities of antioxidant enzymes and cytokines level were measured. Immunohistochemistry and western blot were used to analyse the expression of glial fibrillary acidic protein (GFAP), inducible nitric oxide (iNOS) and NF-kB in ischemic brain. The administration of CH showed marked reduction in infarct size, reduced the neurological deficits, suppressed neuronal loss and downregulate the iNOS, GFAP and NF-kB expression in MCAO rats. A significantly depleted activity of antioxidant enzymes and content of glutathione in MCAO group were protected significantly in MCAO group pretreated with CH. Conversely, the elevated level of thiobarbituric acid reactive species and cytokines in MCAO group was attenuated significantly in CH pretreated group when compared with MCAO group. The results indicated that CH protected the brain from damage caused by MCAO, and this effect may be through downregulation of NF-kB expression.     

Continuous oral administration of atorvastatin ameliorates brain damage after transient focal ischemia in rats

Aims

Pre-treatment with statins is known to ameliorate ischemic brain damage after experimental stroke, and is independent of cholesterol levels. We undertook pre- vs post-ischemic treatment with atorvastatin after focal cerebral ischemia in rats.

Main methods

Male Sprague–Dawley rats underwent transient 90-min middle cerebral artery occlusion (MCAO). Atorvastatin (20 mg/kg/day) or vehicle was administered orally. Rats were divided into vehicle-treated, atorvastatin pre-treatment, atorvastatin post-treatment, and atorvastatin continuous-treatment groups. In the pre-treatment, rats were given atorvastatin or vehicle for 7 days before MCAO. In the post-treatment, rats received atorvastatin or vehicle for 7 days after MCAO. Measurement of infarct volume, as well as neurological and immunohistochemical assessments, were done 24 h and 7 days after reperfusion.

Key findings

Each atorvastatin-treated group demonstrated significant reductions in infarct and edema volumes compared with the vehicle-treated group 24 h after reperfusion. Seven days after reperfusion, infarct volumes in the post-treatment group and continuous-treatment group (but not the pre-treatment group) were significantly smaller than in the vehicle-treated group. Only the continuous-treatment group had significantly improved neurological scores 7 days after reperfusion compared with the vehicle group. Post-treatment and continuous-treatment groups had significantly decreased lipid peroxidation, oxidative DNA damage, microglial activation, expression of tumor necrosis factor-alpha, and neuronal damage in the cortical ischemic boundary area after 7 days of reperfusion.

Significance

These results suggest that continuous oral administration (avoiding withdrawal) with statins after stroke may reduce the extent of post-ischemic brain damage and improve neurological outcome by inhibiting oxidative stress and inflammatory responses.     

Selenium protects cerebral ischemia in rat brain mitochondria

Normal cellular metabolism produces oxidants that are neutralized by the cells' antioxidant enzymes and antioxidants taken from outside. An imbalance between oxidant and antioxidant has been postulated to lead to the neurodegeneration in the ischemic condition. In this study, we have demonstrated the prevention or slowdown of neuronal injury in middle cerebral artery occlusion (MCAO) by sodium selenite. Rats were pretreated with 0.05, 0.1, and 0.2 mg/kg body wt of sodium selenite for 7 d. The rats of group I (sham) and group II (ischemia) were pretreated with physiological saline for 7 d. On d 8, MCAO was induced for 2 h in, the right side of brain of group II, III, IV, and V rats. Brains were dissect out after 22 h of reperfusion and washed with chilled physiological saline. The right cerebral hemisphere was used for the preparation of mitochondria. The activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione-S-transferase, and monoamine oxidase (MAO-A and MAO-B) was depleted significantly; conversely, the activity of poly(ADP-ribosyl) polymerase was elevated significantly as compared to the sham, and the pretreatment of the animals with different doses of sodium selenite has protected the activity of these enzymes significantly. The content of glutathione was decreased significantly, whereas the level of lipid peroxidation was increased significantly in the mitochondria of MCAO as compared to the sham group, and pretreatment with different doses of sodium selenite has protected their levels significantly as compared to the MCAO group. It is concluded that selenium, which is an essential part of our diet, might be helpful in protection against neurodegeneration in cerebral ischemia.     

产前应激对子代大鼠脑缺血/再灌注后星形胶质细胞的影响

目的：探讨产前应激对雄性子代大鼠大脑中动脉缺血/再灌注后星形胶质细胞的影响。方法：SD孕鼠随机分为有产前应激处理（妊娠第15到21天每日3次限制活动）和无产前应激处理,并对其雄性子代大鼠采用线栓法制备大脑中动脉闭塞（MCAO）模型,共分为产前应激+假手术组、MCAO模型组、产前应激+MCAO组（n=10）,于再灌注后第5天检测脑梗死体积,免疫荧光双标染色检测缺血灶边缘区星形胶质细胞形态及促红细胞生成素肝细胞受体A4（EphA4）和胶质纤维酸性蛋白（GFAP）的共表达情况,并采用Western blot检测EphA4、GFAP和神经蛋白聚糖（Neurocan）蛋白表达。结果：产前应激+MCAO组子代大鼠脑梗死体积百分比、EphA4、GFAP和Neurocan蛋白表达均较MCAO组显著增加（P均<0.05）,且GFAP阳性细胞形态学改变及EphA4/GFAP共表达也较MCAO组明显。结论：产前应激可能改变子代大鼠脑缺血/再灌注后星形胶质细胞上EphA4受体的表达,促进星形胶质细胞活化,产生神经蛋白聚糖。     

The Orally Active Noncompetitive AMPAR Antagonist Perampanel Attenuates Focal Cerebral Ischemia Injury in Rats

Inhibition of ionotropic glutamate receptors (iGluRs) is a potential target of therapy for ischemic stroke. Perampanel is a potent noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist with good oral bioavailability and favorable pharmacokinetic properties. Here, we investigated the potential protective effects of perampanel against focal cerebral ischemia in a middle cerebral artery occlusion (MCAO) model in rats. Oral administration with perampanel significantly reduced MCAO-induced brain edema, brain infarct volume, and neuronal apoptosis. These protective effects were associated with improved functional outcomes, as measured by foot-fault test, adhesive removal test, and modified neurological severity score (mNSS) test. Importantly, perampanel was effective even when the administration was delayed to 1 h after reperfusion. The results of enzyme-linked immunosorbent assay (ELISA) showed that perampanel significantly decreased the expression of pro-inflammatory cytokines IL-1β and TNF-α, whereas it increased the levels of anti-inflammatory cytokines IL-10 and TGF-β1 after MCAO. In addition, perampanel treatment markedly decreased the expression of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS), and also inhibited nitric oxide (NO) generation in MCAO-injured rats at 24 and 72 h after reperfusion. In conclusion, this study demonstrated that the orally active AMPAR antagonist perampanel protects against experimental ischemic stroke via regulating inflammatory cytokines and NOS pathways.     

Edaravone ameliorates oxidative stress associated cholinergic dysfunction and limits apoptotic response following focal cerebral ischemia in rat

Stroke is a life-threatening disease with major cause of mortality and morbidity worldwide. The neuronal damage following cerebral ischemia is a serious risk to stroke patients. Oxidative stress and apoptotic damage play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The objective of this study was to test the hypothesis that administration of edaravone (Edv) maintains antioxidant status in brain, improves the cholinergic dysfunction and suppresses the progression of apoptosis response in rat. To test this hypothesis, male Wistar rats were subjected to middle cerebral artery occlusion (MCAO) of 2 h followed by reperfusion for 22 h. Edv was administered (10 mg/kg bwt) intraperitoneally 30 min before the onset of ischemia and 1 h after reperfusion. After reperfusion, rats were tested for neurobehavioral activities and were sacrificed for the infarct volume, estimation of oxidative damage markers. Edv treatment significantly reduced ischemic lesion volume, improved neurological deficits, contended oxidative loads, and suppressed apoptotic damage. In conclusion, treatment with Edv ameliorated the neurological and histological outcomes with elevated endogenous anti-oxidants status as well as reduced induction of apoptotic responses in MCA occluded rat. We theorized that Edv is among the pharmacological agents that reduce free radicals and its associated cholinergic dysfunction and apoptotic damage and have been found to limit the extent of brain damage following stroke.     

Synergistic Effect of Selenium and Melatonin on Neuroprotection in Cerebral Ischemia in Rats

The synergistic scavenger effects of selenium and melatonin collectively we called Se-Mel was studied on the prevention of neuronal injury induced by ischemia/reperfusion. Male Wistar rats were treated with sodium selenite (0.1 mg/kg, i.p.) and melatonin (10 mg/kg, i.p.) 30 min before the middle carotid artery occlusion (MCAO) and immediately after MCAO to male Wistar rats and was continued for 3 days once daily at the interval of 24 h. Behavioral activity (spontaneous motor activity and motor deficit) was improved in Se-Mel-treated rats as compared to MCAO group rats. The level of glutathione and the activity of antioxidant enzymes was depleted significantly while the content of thiobarbituric acid reactive substances, protein carbonyl, and nitric oxide radical (NO^·) was increased significantly in MCAO group. Systemic administration of Se-Mel ameliorated oxidative stress and improves ischemia/reperfusion-induced focal cerebral ischemia. Se-Mel also inhibited inducible nitric oxide synthase expression in Se-Mel+MCAO group as compared to MCAO group rats. Thus, Se-Mel has shown an excellent neuroprotective effect against ischemia/reperfusion injury through an anti-ischemic pathway. In conclusion, we demonstrated that the pretreatment with Se-Mel at the onset of reperfusion, reduced post-ischemic damage, and improved neurological outcome following transient focal cerebral ischemia in male Wistar rat.     

Aminoguanidine Administration Ameliorates Hippocampal Damage After Middle Cerebral Artery Occlusion in Rat

The effects of a selective inducible nitric oxide synthase inhibitor aminoguanidine (AG) on neuronal cells survival in hippocampal CA1 region after middle cerebral artery occlusion (MCAO) were examined. Transient focal cerebral ischemia was induced in rats by 60 or 90 min of MCAO, followed by 7 days of reperfusion. AG treatment (150 mg/kg i.p.) significantly reduced total infarct volumes: by 70% after 90 min MCAO and by 95% after 60 min MCAO, compared with saline-treated ischemic group. The number of degenerating neurons in hippocampal CA1 region was also markedly lower in aminoguanidine-treated ischemic groups compared to ischemic groups without AG-treatment. The number of iNOS-positive cells significantly increased in the hippocampal CA1 region of ischemic animals, whereas it was reduced in AG-treated rats. Our findings demonstrate that aminoguanidine decreases ischemic brain damage and improves neurological recovery after transient focal ischemia induced by MCAO.     

Kaempferol Mediated AMPK/mTOR Signal Pathway Has a Protective Effect on Cerebral Ischemic-Reperfusion Injury in Rats by Inducing Autophagy

Ischemia/reperfusion (I/R) caused by ischemic stroke treatments leads to brain injury and its pathological mechanism is related to autophagy. The underlying mechanism of kaempferol on cerebral I/R injury needs to be explored. To establish I/R injury, we used a middle cerebral artery occlusion-reperfusion (MCAO) model in rats. MCAO rats were treated with the same amount of saline (I/R group); Treatment group rats were treated orally with kaempferol (50, 100, 200 mg/kg) for 7 days before surgery. After reperfusion for 24 h, the scores of neurological deficits and infarct volume in each group were evaluated. LC3, Beclin-1 p62, AMPK and mTOR protein expression levels were examined by TTC staining, immunofluorescence staining, qRT-PCR and western blotting assay. H&E and TTC staining showed that compared with model group, the infarction size of rats in kaempferol group was markedly reduced. Meanwhile, the results showed that kaempferol had a dose-dependent nerve function repairability. Nissl and TUNEL staining showed that kaempferol could reduce neuronal apoptosis and ameliorate neuronal impairment after I/R. Western blotting and qRT-PCR results showed that kaempferol could protect the brain from ischemia reperfusion by activating autophagy. In addition, add AMPK inhibitor, western blotting and immumohistochemical staining showed that kaempferol mediated AMPK/mTOR signal pathway in MCAO rats. Kaempferol could mediate the AMPK signal pathway to regulate autophagy and inhibit apoptosis to protect brain against I/R injury.

     

Sesamin attenuates behavioral,biochemical and histological alterations induced by reversible middle cerebral artery occlusion in the rats

Restoration of blood flow to an ischemic brain region is associated with generation of reactive oxygen species (ROS) with consequent reperfusion injury. ROS cause lipid peroxidation, protein oxidation, and DNA damage, all of which are deleterious to cells. So diminishing the production of free radicals and scavenging them may be a successful therapeutic strategy for the protection of brain tissue in cerebral stroke. The present study investigated the neuroprotective effect of sesamin (Sn) to reduce brain injury after middle cerebral artery occlusion (MCAO). The middle cerebral artery (MCA) of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. Sesamin is the most abundant lignan in sesame seed oil is a potent antioxidant. Sesamin (30 mg/kg) was given orally twice, 30 min before the onset of ischemia and 12 h after reperfusion. The initial investigations revealed that sesamin reduced the neurological deficits in terms of behavior and reduced the level of thiobarbituric acid reactive species (TBARS), and protein carbonyl (PC) in the different areas of the brain when compared with the MCAO group. A significantly depleted level of glutathione and its dependent enzymes (glutathione peroxidase [GPx] and glutathione reductase [GR]) in MCAO group were protected significantly in MCAO group treated with sesamin. The present study suggests that sesamin may be able to attenuate the ischemic cell death and plays a crucial role as a neuroprotectant in regulating levels of reactive oxygen species in the rat brain. Thus, sesamin may be a potential compound in stroke therapy.     

Possible Involvement of PTEN Signaling Pathway in the Anti-apoptotic Effect of Electroacupuncture Following Ischemic Stroke in Rats

As a traditional therapeutic method, electroacupuncture (EA) has been adopted as an alternative therapy for stroke recovery. Here, we aimed to evaluate whether EA therapy at points of Quchi (LI11) and Zusanli (ST36) alleviated neuronal apoptosis by PTEN signaling pathway after ischemic stroke. A total of 72 male Sprague–Dawley rats were randomized into three groups, including sham group, MCAO group, and EA group. EA was initiated after 24 h of reperfusion for 3 consecutive days. At 72 h following ischemia/reperfusion, neurological deficits, infarct volumes, and TUNEL staining were evaluated and the PTEN pathway-related proteins together with apoptosis-related proteins were detected. The results indicated that EA treatment significantly decreased cerebral infarct volume, neurological deficits and alleviated proportion of apoptotic cells in cerebral ischemic rats. Furthermore, EA significantly up-regulated the phosphorylation levels of PDK1, Akt(Thr308), GSK-3β, and down-regulated the phosphorylation levels of PTEN, Akt(Ser473) in the peri-infarct cortex. EA treatment significantly reduced the up-regulation of caspase-3, cleaved-caspase-3, Bim, and reversed the reduction of Bcl-2 induced by the ischemic stroke. These findings suggest that EA treatment at points of Quchi (LI11)- and Zusanli (ST36)-induced neuroprotection might involve inhibition of apoptosis via PTEN pathway.     

银杏叶提取物促进脑缺血半暗带神经元自噬提高神经保护作用

银杏叶提取物(ginkgo biloba extract-761,EGb-761)注射液在中国常作为辅助药物被用于治疗脑卒中,但是,其潜在的细胞和药理机制尚未完全了解。该研究旨在探讨EGb-761是否通过调节缺血性脑卒中半暗带神经元的自噬从而发挥保护作用。采用雄性SD大鼠大脑中动脉闭塞(middle cerebral artery occlusion,MCAO)再灌注模型,将MCAO大鼠随机分为5组,分别为Sham组、MCAO+saline组、MCAO+EGb组、MCAO+EGb+3-MA组和MCAO+3-MA组。脑缺血大鼠用EGb-761药物腹腔注射7天后,并使用自噬抑制剂3-MA侧脑室注射进行干预,分别通过蛋白免疫印迹法(WB)、实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)和免疫荧光检测缺血半暗带的脑组织,以检测自噬的表达。另外,根据脑梗死体积、神经功能缺损和TUNEL检测神经元凋亡水平,以评估治疗效果。结果表明,与MCAO+saline相比,MCAO+EGb组的EGb-761显著提高了神经元自噬水平,同时,明显减轻了神经功能缺损、脑梗死面积和神经元凋亡。此外,相对于MCAO+EGb组,MCAO+EGb+3-MA组中的3-MA抵消了EGb增强神经元自噬的功效,并且仅使用3-MA继续加重了神经损伤。因此,EGB-761通过特异性促进脑缺血半暗带神经元自噬发挥神经保护作用。     

Quercetin Protects Against Oxidative Stress Associated Damages in a Rat Model of Transient Focal Cerebral Ischemia and Reperfusion

Experimental studies have demonstrated that oxidative stress and apoptosis play an important role in cerebral ischemic pathogenesis and may represent a target for treatment. The purpose of this study was to determine whether the quercetin dihydrate (Q) protects against cerebral ischemia neuronal damage. Male Wistar rats were subjected to transient middle cerebral artery occlusion (MCAO) for 2?h and reperfused for 72?h. Quercetin (30?mg/kg, i.p) was administrated 30?min before the onset of ischemia and after the ischemia at interval of 0, 24, 48, and 72?h. The administration of Q showed marked reduction in infarct size, reduced the neurological deficits in terms of behaviors, suppressed neuronal loss and diminished the p53 expression in MCAO rats. Q was found to be successful in upregulating the antioxidant status and lowering the TBARS level. Conversely, the elevated activity of poly (ADP-ribose) polymerase (PARP), and activity of caspase-3 in MCAO group was attenuated significantly in Q treated group when compared with MCAO group. Our study reveals that Q, as a powerful antioxidant, could prevent free radicals associated oxidative damage and morphological changes in the MCAO rats. Thus, it may have a therapeutic value for the treatment of stroke.     

Neuroprotective Potential of Fasudil Mesylate in Brain Ischemia-Reperfusion Injury of Rats

We previously reported that inhibition of Rho-kinase (ROCK) by hydroxyl fasudil improves cognitive deficit and neuronal damage in rats with chronic cerebral ischemia (Huang et al., Cell Mol Neurobiol 28:757–768, 2008). In this study, fasudil mesylate (FM) was investigated for its neuroprotective potential in rats with ischemia following middle cerebral artery occlusion (MCAO) and reperfusion. The effect of fasudil mesylate was also studied in rat brain cortical and hippocampal slices treated with oxygen-glucose deprivation (OGD) injury. Gross anatomy showed that cerebral infarct size, measured with 2,3,5-triphenyltetrazolium chloride (TTC) staining, was significantly smaller in the FM-treated than in the non-FM-treated ischemic rats. In the brain regions vulnerable to ischemia of ischemic rats, fasudil mesylate was also found to significantly restore the enzyme protein expression level of endothelial nitric oxide synthase (eNOS), which was decreased in ischemia. However, it remarkably reduced the protein synthesis of inducible nitric oxide synthase (iNOS) that was induced by ischemia and reperfusion. In rat brain slices treated with OGD injury, fasudil mesylate increased the neuronal cell viability by 40% for cortex and by 61% for hippocampus, respectively. Finally, in the presence of OGD and fasudil mesylate, superoxide dismutase (SOD) activity was increased by 50% for cortex and by 58% for hippocampus, compared to OGD only group. In conclusion, our in vivo study showed that fasudil mesylate not only decreased neurological deficit but also reduced cerebral infarct size, possibly and at least partially by augmenting eNOS protein expression and inhibiting iNOS protein expression after ischemia-reperfusion. Xian-Ju Huang contributed equally to this article.     

Propofol Protects Against Focal Cerebral Ischemia via Inhibition of Microglia-Mediated Proinflammatory Cytokines in a Rat Model of Experimental Stroke

Ischemic stroke induces microglial activation and release of proinflammatory cytokines, contributing to the expansion of brain injury and poor clinical outcome. Propofol has been shown to ameliorate neuronal injury in a number of experimental studies, but the precise mechanisms involved in its neuroprotective effects remain unclear. We tested the hypothesis that propofol confers neuroprotection against focal ischemia by inhibiting microglia-mediated inflammatory response in a rat model of ischemic stroke. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h followed by 24 h of reperfusion. Propofol (50 mg/kg/h) or vehicle was infused intravenously at the onset of reperfusion for 30 minutes. In vehicle-treated rats, MCAO resulted in significant cerebral infarction, higher neurological deficit scores and decreased time on the rotarod compared with sham-operated rats. Propofol treatment reduced infarct volume and improved the neurological functions. In addition, molecular studies demonstrated that mRNA expression of microglial marker Cd68 and Emr1 was significantly increased, and mRNA and protein expressions of proinflammatory cytokines tumor necrosis factor-α, interleukin-1β and interleukin-6 were augmented in the peri-infarct cortical regions of vehicle-treated rats 24 h after MCAO. Immunohistochemical study revealed that number of total microglia and proportion of activated microglia in the peri-infarct cortical regions were markedly elevated. All of these findings were ameliorated in propofol-treated rats. Furthermore, vehicle-treated rats had higher plasma levels of interleukin-6 and C-reactive protein 24 h after MCAO, which were decreased after treatment with propofol. These results suggest that propofol protects against focal cerebral ischemia via inhibition of microglia-mediated proinflammatory cytokines. Propofol may be a promising therapeutic agent for the treatment of ischemic stroke and other neurodegenerative diseases associated with microglial activation.     

Theaflavin ameliorates cerebral ischemia-reperfusion injury in rats through its anti-inflammatory effect and modulation of STAT-1

Theaflavin, a major constituent of black tea, possesses biological functions such as the antioxidative, antiviral, and anti-inflammatory ones. The purpose of this study was to verify whether theaflavin reduces focal cerebral ischemia injury in a rat model of middle cerebral artery occlusion (MCAO). Male Sprague-Dawley rats were anesthetized and subjected to 2 hours of MCAO followed 24 hours reperfusion. Theaflavin administration (5, 10, and 20 mg/kg, i.v.) ameliorated infarct and edema volume. Theaflavin inhibited leukocyte infiltration and expression of ICAM-1, COX-2, and iNOS in injured brain. Phosphorylation of STAT-1, a protein which mediates intracellular signaling to the nucleus, was enhanced 2-fold over that of sham group and was inhibited by theaflavin. Our study demonstrated that theaflavin significantly protected neurons from cerebral ischemia-reperfusion injury by limiting leukocyte infiltration and expression of ICAM-1, and suppressing upregulation of inflammatory-related prooxidative enzymes (iNOS and COX-2) in ischemic brain via, at least in part, reducing the phosphorylation of STAT-1.     

Probenecid Protects Against Transient Focal Cerebral Ischemic Injury by Inhibiting HMGB1 Release and Attenuating AQP4 Expression in Mice

Stroke results in inflammation, brain edema, and neuronal death. However, effective neuroprotectants are not available. Recent studies have shown that high mobility group box-1 (HMGB1), a proinflammatory cytokine, contributes to ischemic brain injury. Aquaporin 4 (AQP4), a water channel protein, is considered to play a pivotal role in ischemia-induced brain edema. More recently, studies have shown that pannexin 1 channels are involved in cerebral ischemic injury and the cellular inflammatory response. Here, we examined whether the pannexin 1 channel inhibitor probenecid could reduce focal ischemic brain injury by inhibiting cerebral inflammation and edema. Transient focal ischemia was induced in C57BL/6J mice by middle cerebral artery occlusion (MCAO) for 1 h. Infarct volume, neurological score and cerebral water content were evaluated 48 h after MCAO. Immunostaining, western blot analysis and ELISA were used to assess the effects of probenecid on the cellular inflammatory response, HMGB1 release and AQP4 expression. Administration of probenecid reduced infarct size, decreased cerebral water content, inhibited neuronal death, and reduced inflammation in the brain 48 h after stroke. In addition, HMGB1 release from neurons was significantly diminished and serum HMGB1 levels were substantially reduced following probenecid treatment. Moreover, AQP4 protein expression was downregulated in the cortical penumbra following post-stroke treatment with probenecid. These results suggest that probenecid, a powerful pannexin 1 channel inhibitor, protects against ischemic brain injury by inhibiting cerebral inflammation and edema.     

亚低温联合镁剂对脑缺血再灌注大鼠保护作用的研究

目的:rt-PA溶栓为缺血性卒中最有效的治疗方法,脑血流再通后挽救濒临死亡的神经细胞同时,也可能发生更为严重而持久的脑缺血再灌注损伤。本研究探讨联合应用局部亚低温(32-35℃)及硫酸镁对局灶性脑缺血再灌注大鼠的保护作用及其可能机制。方法:通过线栓法建立大鼠大脑中动脉阻塞(MCAO)及再通模型,将50只雄性Wistar大鼠随机分为假手术组、常温组、亚低温组、硫酸镁组、亚低温+硫酸镁组,每组10例,采用Longa神经功能评分、TTC染色、干湿重法、TUNEL技术,检测和比较各组脑缺血再灌注后大鼠的神经功能、脑梗死体积、脑组织含水量及凋亡细胞数。结果:与常温组相比,亚低温组与亚低温+硫酸镁组的梗死体积、神经功能评分、脑组织含水量、凋亡细胞数均明显降低,差异有显著意义(P0.05);而与亚低温组相比,亚低温+硫酸镁组局灶脑缺血大鼠的脑梗死体积、神经功能评分、脑组织含水量、凋亡细胞数均显著减少,差异有显著意义(P0.05)。结论:与单独应用亚低温相比,局部亚低温与硫酸镁联合应用,对局灶性脑缺血再灌注大鼠可发挥更有效的脑保护作用。其机制可能与抑制脑缺血再灌注后凋亡及减轻脑水肿有关。二者联用可能为缺血性卒中患者提供一种减轻溶栓后再灌注损伤的有效脑保护方法。     

Histone deacetylase 6 interference protects mice against experimental stroke-induced brain injury via activating Nrf2/HO-1 pathway

Cerebral stroke is a fatal disease with increasing incidence. The study was to investigate the role and mechanism of Histone deacetylase 6 (HDAC6) on experimental stroke-induced brain injury. The recombinant shRNA-HDAC6 or scramble shRNA lentivirus was transfected to ICR mice. Then, the ischemia/reperfusion injury (I/RI) mice were constructed using middle cerebral artery occlusion (MCAO) method. Brain TTC staining was used to determine infarct areas. Serum levels of oxidative stress-related factors were detected by enzyme linked immunosorbnent assay (ELISA). Realtime-qPCR (RT-qPCR) and Western blot were used to respectively detect mRNA and protein levels. HDAC6 was up-regulated in brain I/RI mice (MCAO group), and down-regulated again in MCAO mice transfected with shRNA-HDAC6 (MCAO?+?shRNA group). The infarct area of the MCAO mice was increased, neurological scores were higher, and serum protein levels of 3-NT, 4-HNE and 8-OHdG were higher. HDAC6 interference attenuated above effects. Though protein levels of Nrf2 and HO-1 in cytoplasm increased slightly in MCAO group, they increased significantly by HDAC6 interference. The protein levels of Nrf2 in cytoblast decreased significantly in MCAO group, and increased markedly by HDAC6 interference. HDAC6 interference protected mice against experimental stroke-induced brain injury via Nrf2/HO-1 pathway.     

改良线栓法大鼠大脑中动脉阻塞模型的建立

目的对大鼠大脑中动脉阻塞（MCAO）再灌注模型进行改良,通过比较再灌注24h时大鼠神经功能评分、梗死率、模型制作时间、成功率和死亡率等指标评价改良线栓法大鼠MCAO再灌注模型的有效性。方法12只SD大鼠随机分为对照和模型两组,对照组采用分离结扎翼腭动脉,从颈外动脉插入线栓至大脑中动脉。模型组采用不分离结扎翼腭动脉,从颈总动脉分叉处插入线栓至大脑中动脉。阻断大脑中动脉血供2h后将线栓拔出实现再灌注。于再灌注24h时观察脑组织组织病理学改变,计算比较两组大鼠神经功能评分、模型制作时间、模型成功率和死亡率以及鼠脑切片TTC染色测量脑梗死率。结果两组MCAO模型在再灌注24h后大鼠神经功能评分、梗死率、模型成功率和死亡率等方面没有显著差异;模型组的模型制作时间显著少于对照组（P〈0．05）。结论采用不分离结扎翼腭动脉,由颈总动脉插入线栓的改良线栓法是稳定和可靠的MCAO造模方法。