Srs11-92, a ferrostatin-1 analog,improves oxidative stress and neuroinflammation via Nrf2 signal following cerebral ischemia/reperfusion injury

Aim

Ferroptosis is increasingly becoming to be considered as an important mechanism of pathological cell death during stroke, and specific exogenous ferroptosis inhibitors have the ability to reverse cerebral ischemia/reperfusion injury. However, research on Srs11-92 (AA9), a ferrostatin-1 (Fer-1) analog, in preclinical studies is limited.

Methods

In the middle cerebral artery occlusion-reperfusion (MCAO/R) mice model or oxygen–glucose deprivation/reperfusion (OGD/R) cell model, Fer-1, AA9, and/or ML385 were administered, and brain infarct size, neurological deficits, neuronal damage, oxidative stress, and neuroinflammation were determined after the damage, in vitro and in vivo.

Results

Fer-1 and AA9 improved brain infarct size, neuronal damage, and neurological deficits in mice model of MCAO/R, and inhibited the overloaded iron deposition, ROS accumulation, and neuroinflammation response: it also increased the expression of GPx4, Nrf2, and HO-1 and suppressed the expression of HMGB1 and NF-κB p65 in the epicenter of injured hippocampal formation. However, Nrf2 inhibitor ML385 reversed the neuroprotective effect of AA9, including the oxidative stress and neuroinflammation. In vitro studies showed that AA9 relieved OGD/R-induced neuronal oxidative stress and neuroinflammation via the Nrf2 pathway, which was impaired by ML385 in primary neurons.

Conclusion

The findings imply that Fer-1 analog AA9 may be suitable for further translational studies for the protection of neuronal damage via Nrf2 signal pathway-mediated oxidative stress and neuroinflammation in stroke and others neurological diseases.     

Remote limb ischemic postconditioning protects mouse brain against cerebral ischemia/reperfusion injury via upregulating expression of Nrf2, HO-1 and NQO-1 in mice

Remote ischemic postconditioning (RIPostC) is a promising therapeutic intervention, which has been discovered to reduce ischemia/reperfusion (I/R) injury in heart, kidney, brain and skeletal muscle experimentally. However, its potential protective mechanisms have not been well elucidated. The aim of this study was to investigate the protective effect of RIPostC in cerebral I/R injury and explore the new putative mechanisms of neuroprotection elicited by it. Focal cerebral ischemia was induced by transient middle cerebral artery occlusion (tMCAO) in male CD1 mice. RIPostC was generated by three cycles of 5-min reperfusion/5-min occlusion of the bilateral femoral artery on the bilateral limbs at the onset of middle cerebral artery reperfusion. RIPostC significantly improved neurological outcome, lessened infarct volume and brain edema, upregulated the expression of Nuclear factor erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1) and quinone oxidoreductase-1 (NQO-1) and activity of superoxide dismutase (SOD), and downregulaed the formation of malondialdehyde (MDA) (p < 0.05). Taken together, these findings demonstrated that RIPostC protected the brain from I/R injury after focal cerebral ischemia by reducing oxidative stress and activating the Nrf2–ARE (antioxidant response element) pathway.     

Detrimental effects of post-treatment with fatty acids on brain injury in ischemic rats

Studies have illustrated that fatty acids, especially polyunsaturated fatty acids (PUFA), have a role in regulating oxidative stress via the enhancement of antioxidative defense capacity or the augmentation of oxidative burden. Elevated oxidative stress has been implicated in the pathogenesis of brain injury associated with cerebral ischemia/reperfusion (I/R). The objective of this study was to assess whether treatment with fatty acids after focal cerebral I/R induced by occlusion of the common carotid arteries and the middle cerebral artery has effects on brain injury in a rat model. PUFA, including arachidonic acid (AA) and docosahexaenoic acid (DHA), and the saturated fatty acid, stearic acid (SA), were administrated 60 min after reperfusion via intraperitoneal injection. AA and DHA aggravated cerebral ischemic injury, which manifested as enlargement of areas of cerebral infarction and increased impairment of motor activity, in a concentration-dependent manner. However, there were no remarkable differences in post-ischemic alterations between the SA and saline groups. The post-ischemic augmentation of injury in AA and DHA treatment groups was accompanied by increases in the permeability of the blood-brain barrier (BBB), brain edema, metalloproteinase (MMP) activity, inflammatory cell infiltration, cyclooxygenase 2 (COX-2) expression, caspase 3 activity, and malondialdehyde (MDA) production, and by a decrease in the brain glutathione (GSH) content. Furthermore, we found that either AA or DHA alone had little effect on free radical generation in neuroglia, but they greatly increased the hydrogen peroxide-induced oxidative burden. Taken together, these findings demonstrate the detrimental effect of PUFA such as AA and DHA in post-ischemic progression and brain injury after cerebral I/R is associated with augmentation of cerebral I/R-induced alterations, including oxidative changes.     

Chemokine receptor 7 mediates miRNA-182 to regulate cerebral ischemia/reperfusion injury in rats

Aims

Chemokine receptor 7 (CXCR7) exerts protective effects on the brain. MicroRNAs (miRNAs) are involved in cerebral ischemia/reperfusion (I/R) injury, but their involvement in CXCR7-mediated brain protection is unknown. In this study, we investigated the role of miRNAs in CXCR7-mediated brain protection.

Methods

CXCR7 levels in peripheral blood samples from patients with acute ischemic stroke (AIS) and ischemic penumbra area brain tissues from middle cerebral artery occlusion (MCAO) rats after recanalization were measured. An miRNA microarray analysis was performed to examine the expression of miRNAs caused by CXCR7 knockdown in ischemic penumbra area brain tissue in middle cerebral artery occlusion–reperfusion rats and to predict corresponding downstream target genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed the most enriched pathways. A dual-luciferase reporter assay confirmed the direct regulation of miR-182 on the target gene TCF7L2. The correlation between TCF7L2 and CXCR7/miR-182 was verified using rescue assays.

Results

CXCR7 expression was upregulated in MCAO rats and mechanical thrombectomy patients with AIS compared to that in controls. The motor and sensory functions of MCAO rats with CXCR7 knockdown further decreased, and the infarct volume and cerebral edema increased. miRNA microarray data showed that seven miRNAs were differentially expressed after shRNA-CXCR7 treatment. The dual-luciferase reporter assay confirmed that miR-182 directly targeted the TCF7L2 gene. Rescue assays confirmed that TCF7L2 is downstream of CXCR7/miR-182. KEGG pathway analysis showed that the Hippo pathway may be a key pathway in CXCR7 upregulation and plays a role in protecting the brain after interventional surgery. Animal experiments have shown that CXCR7-mediated cerebral I/R injury promotes the phosphorylation of key molecules YAP and TAZ in the Hippo pathway.

Conclusion

CXCR7 protects against cerebral I/R injury, possibly via the miR-182/TCF7L2/Hippo pathway. These results indicate that CXCR7 affects cerebral ischemia–reperfusion injury through miRNA regulation and downstream pathways.     

MiR-139 protects against oxygen-glucose deprivation/reoxygenation (OGD/R)-induced nerve injury through targeting c-Jun to inhibit NLRP3 inflammasome activation

BackgroundCerebral ischemia/reperfusion (I/R) injury after ischemic stroke is usually accompanied with the activation of inflammasome which seriously impairs neurological function. MiR-139 has been reported to be associated with inflammatory regulation in multiple diseases. However, its effect and mechanism on inflammation regulation after cerebral I/R injury are still poorly understood.MethodsAn in vitro model of cerebral I/R injury was constructed with oxygen-glucose deprivation/reoxygenation (OGD/R) treatment. TargetScan bioinformatics analysis and dual luciferase reporter assay were utilized to confirm the targeted relationship between miR-139 and c-Jun. Cell pyroptosis was verified by flow cytometry and Caspase-1 Detection Kit. qRT-PCR assay was performed to detect the expression levels of miR-139, c-Jun, NLRP3 and ASC. Western blotting was applied to measure the protein levels of c-Jun and pyroptosis-related markers NLRP3, ASC, caspase-1, GSDMD^Nterm. The ELISA assay was applied to measure the release of IL-1β, IL-18 and LDH.ResultsMiR-139 was significantly downregulated whereas c-Jun was obviously upregulated after OGD/R treatment. TargetScan analysis predicted that c-Jun was a potential target of miR-139, which was verified by the dual-luciferase reporter assay. Also, overexpression of miR-139 repressed c-Jun expression. Furthermore, miR-139 inhibited OGD/R-induced cell pyroptosis and the upregulation of NLRP3, caspase-1, ASC, GSDMD^Nterm, and the release of IL-1β, IL-18 and LDH, while miR-139 inhibition exerted the opposite effects. However, overexpression of c-Jun aggravated OGD/R-induced nerve injury and partly abolished the neuroprotective effect of miR-139.ConclusionUpregulation of miR-139 exerted neuroprotection against OGD/R-induced nerve injury by negatively regulating c-Jun/NLRP3 inflammasome signaling. This study offered insights for providing potential therapeutic targets for treating cerebral I/R injury.     

MiR-107 Aggravates Oxygen-Glucose Deprivation/Reoxygenation (OGD/R)-Induced Injury Through Inactivating PI3K-AKT Signalling Pathway by Targeting FGF9/FGF12 in PC12 Cells

ObjectivesThe aberrant expression of miR-107 has been confirmed in some neurological diseases, including ischemic stroke (IS). However, the function of miR-107 and underlying mechanisms are ambiguous.Materials and methodsOxygen-Glucose Deprivation/Reoxygenation (OGD/R)-induced PC12 cells were used to mimic IS condition. MiR-107 expression and differentially expressed genes (DEGs) responding to IS were analyzed by GSE97532 and GSE61616 datasets, respectively. The target genes of miR-107 were predicted by TargetScan and confirmed by dual-luciferase reporter assay. Cell counting kit-8 and apoptosis assays were conducted to explore the role of miR-107 in biological behaviors of OGD/R-induced PC12 cells.ResultsBioinformatics analysis revealed that miR-107 expression was elevated in rats with middle cerebral artery occlusion (MCAO), which was confirmed in OGD/R-treated PC12 cells. Notably, miR-107 strongly inhibited the proliferation of OGD/R-treated PC12 cells. As most DEGs were enriched in PI3K-AKT signaling pathway, which was critical for IS, DEGs in this pathway was compared with the down-regulated genes and the predicted genes to obtain potential target genes of miR-107, and ultimately fibroblast growth factor (FGF)9 and FGF12 stood out. The experiments demonstrated that miR-107 inhibited viability and promoted apoptosis of OGD/R-treated PC12 cells by down-regulating FGF9/FGF12 level. Mechanically, for the first time, we clarified the mechanism via which miR-107 inactivated PI3K-AKT signaling pathway by targeting FGF9/FGF12.ConclusionsWe summarized that miR-107 aggravates OGD/R-induced injury through inactivating PI3K-AKT signaling pathway via targeting FGF9/FGF12. Therefore, our study elucidates the neurotoxicity of miR-107 in IS development and provides a new promising therapy strategy for IS.     

The protective effect of SCR15-18 on cerebral ischemia-reperfusion injury

Abstract

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Objectives: Soluble complement receptor type 1 (sCR1), a potent inhibitor of complement activation, has been shown to protect brain cells against cerebral ischemic/reperfusion (CI/R) injury due to its decay-accelerating activity for C3/C5 convertase and co-factor activity for C3b/C4b degradation. However, the effect of short consensus repeats (SCRs) 15-18, one of active domains of sCR1 with high C3b/C4b degradability, has not been demonstrated. Here, we investigated the protective effect of recombinant SCR_15-18 protein in middle cerebral artery occlusion (MCAO)-induced focal CI/R injury.

Methods: Recombinant SCR_15-18 protein was successfully expressed in Escherichia coli and refolded to its optimal bioactivity. Seventy-five Sprague-Dawley rats were randomly assigned into three groups: sham-operated group, CI/R group, and SCR_15-18+CI/R group pretreated with 20 mg/kg SCR_15-18 protein. After 2 hours of MCAO and subsequent 24 hours of reperfusion, rats were evaluated for neurological deficits and cerebral infarction. Polymorphonuclear leukocyte accumulation, C3b deposition, and morphological changes in cerebral tissue were also estimated.

Results: SCR_15-18 pretreatment induced a 20% reduction of infarct size and an improvement of neurological function with 22·2% decrease of neurological deficit scores. Inhibition of cerebral neutrophils infiltration by SCR_15-18 was indicated from the reduction of myeloperoxidase activity in SCR_15-18+CI/R rats. Decreased C3b deposition and improved morphological changes were also found in cerebral tissue of SCR_15-18-treated rats.

Discussion: Our studies suggest a definitive moderately protective effect of SCR_15-18 against CI/R damage and provide preclinical experimental evidence supporting the possibility of using it as a small anti-complement therapeutic agent for CI/R injury therapy.     

动员自体骨髓干细胞对大鼠脑缺血／再灌注损伤及细胞凋亡的影响

目的 探讨应用G-CSF动员自体骨髓干细胞对大鼠脑缺血／再灌注损伤及细胞凋亡的影响。方法 应用线栓法制备大鼠局灶性大脑中动脉栓塞／再灌注(MCAO／R)模型，应用粒细胞集落刺激因子(G-GSF)刺激自体骨髓干细胞分裂增殖，并用5-溴脱氧尿核苷(Brdu)标记。观察大鼠神经病学评分，HE染色和免疫组化检测脑缺血区病理改变及CD34和Brdu阳性细胞，原位末端标记法(TUNEL法)观察细胞凋亡。结果 模型动员组大鼠脑缺血／再灌注后24h，大量炎症细胞浸润。再灌注后48h，缺血区可见CD34和Brdu阳性细胞；72h后CD34阳性细胞消失，而Brdu阳性细胞持续存在；模型未动员组缺血区无CD34和很少Brdu阳性细胞表达。48h缺血区新生毛细血管密度明显高于对照组。再灌注后24h细胞凋亡显著，1周时达高峰；与模型非动员组比较，模型动员组48h后细胞凋亡改善明显。结论 自体骨髓干细胞经G-CSF动员后可向大鼠脑缺血区趋化并可分化为神经元前体细胞，显著促进脑缺血区血管再生，降低脑神经功能评分，降低细胞凋亡率。     

Exosomes Released from Bone-Marrow Stem Cells Ameliorate Hippocampal Neuronal Injury Through transferring miR-455-3p

BackgroundThe neuroprotective roles of mesenchymal stem cells (MSCs) in brain injury are elicited at least partially through the secretion exosomes containing microRNAs (miRNAs). We herein investigate the protective function of bone marrow MSCs (BMSCs)-derived exosomes harboring miR-455-3p against hippocampal neuronal injury in mouse and N2a cell damage model.MethodsFirst, BMSC surface markers were detected by flow cytometry, followed by extraction of BMSCs-derived exosomes (BMSCs-Exos). A mouse model of neuronal injury was induced by middle cerebral artery occlusion/reperfusion (MCAO/R), and N2a cells were exposed to oxygen-glucose deprivation/reoxygenation (OGD/R) for in vitro experiments. BMSCs-Exos were administrated in mice and N2a cells. We subsequently determined viability- and apoptosis-features using EdU staining, CCK-8, flow cytometry and Caspase-3 kits. Subsequently, we used RT-qPCR to assess miR-455-3p expression in brain tissues as well as N2a cells, and bioinformatic tools to predict the targeting mRNA of miR-455-3p, which was validated by dual-luciferase assays.ResultsBMSCs-Exos improved hippocampal neuronal injury in MCAO/R-treated mice and OGD/R-induced injury to N2a cells. BMSCs-Exos upregulated miR-455-3p expression in brain tissues of mice and OGD/R-treated N2a cells. miR-455-3p targeted and conversely regulated PDCD7 expression. The protective effect of BMSCs-Exos on OGD/R-treated N2a cells was markedly mitigated following miR-455-3p downregulation. Moreover, overexpression of miR-455-3p contributed to increased N2a cell activity and decreased apoptosis, while the rescue experiment results were opposite.ConclusionMSCs-derived exosomal miR-455-3p targeted PDCD7 to alleviate hippocampal neuronal injury in MCAO/R-treated mice and injury of OGD/R-treated N2a cells.     

大鼠早期局灶性脑缺血再灌注损伤中USP10的表达水平变化及其与自噬的关系

目的 探讨早期局灶性脑缺血再灌注损伤大鼠模型中再灌注不同时间点USP10的表达水平变化及其与自噬的关系。方法 将36只成年雄性SD大鼠随机分成4组:假手术组、脑缺血2 h再灌注6 h模型组、脑缺血2 h再灌注12 h模型组、脑缺血2 h再灌注24 h模型组; 采用线栓法致大脑中动脉栓塞(middle cerebral artery occlusion, MCAO)制备大鼠局灶性脑缺血再灌注模型,给予神经行为学评分,用TTC染色法测定脑梗死体积,透射电镜观察梗死周边区皮层神经元自噬,Western blot 法检测梗死周边区皮层USP10和自噬相关蛋白LC3B的表达水平,免疫荧光双标法检测梗死周边区皮层神经元中USP10及LC3B的表达水平变化。结果 免疫荧光双标显示模型组自噬蛋白阳性细胞数与存活神经元数均于再灌注12 h最多(P<0.05),二者某种程度上趋势一致; Western blot免疫荧光双标均显示与假手术组相比,USP10及LC3B蛋白在模型组中表达上调(P<0.01),且于再灌注12 h组达到高峰(P<0.05); 透射电镜显示再灌注不同时间点自噬强度的变化与免疫荧光自噬蛋白表达水平的趋势基本一致。结论 早期脑I/R损伤中自噬的激活某种程度上可减轻神经元的损伤,而USP10可能通过某种机制调控脑I/R中自噬的发生发展。     

CircTLK1通过miR-424-5p/FBXO3轴对氧糖剥夺/复氧诱导的神经细胞损伤的影响

目的 探讨环状RNA TLK1(CircRNA TLK1,CircTLK1)对氧糖剥夺/复氧(Oxygen glucose deprivation/Reoxygenation,OGD/R)诱导的神经元HT22损伤的影响以及对微小RNA(microRNA,miR)-424-5p/F-box蛋白3(F-box protein 3,FBXO3)的调控作用。方法 将HT22细胞分为对照组、OGD/R组、sh-NC组、沉默环状RNA TLK1(Silencing circular RNA tlk1,sh-circTLK1)组、sh-circTLK1+抑制剂NC组、sh-circTLK1+miR-424-5p抑制剂组、sh-circTLK1+miR-424-5p抑制剂+sh NC组、sh-circTLK1+miR-424-5p抑制剂+sh FBXO3组,除对照组外其余各组细胞均行OGD/R操作,细胞计数试剂盒8(Cell counting Kit 8,CCK-8)法测定HT22细胞活力; 脂连蛋白V-异硫氰酸荧光素(Adiponectin V-fluorescein isothiocyanate,Annexin V-FITC)细胞凋亡试剂盒测定HT22细胞凋亡; 测定HT22细胞乳酸脱氢酶(Lactate dehydrogenase,LDH)漏出率; 实时荧光定量聚合酶链反应(Real time fluorescent quantitative polymerase chain reaction,RT-qRCR)法测定HT22细胞miR-424-5p,FBXO3 mRNA水平; 蛋白免疫印记法(Western Blot)检测B淋巴细胞瘤-2关联基因X(B lymphoma-2 gene association X,Bax)、活化半胱天冬酶-3(Cleaved caspase-3)、FBXO3水平; 双荧光素酶测定CircTLK1与miR-424-5p以及miR-424-5p与FBXO3靶向关系,并使用RNA下拉实验验证CircTLK1与miR-424-5p关系。结果 与对照组比较,OGD/R组miR-424-5p,HT22细胞活力降低(P<0.05),circTLK1,FBXO3 mRNA水平,HT22细胞凋亡率、Bax,Cleaved caspase-3水平、LDH漏出率升高(P<0.05); 与OGD/R组比较,sh-circTLK1组HT22细胞活力增加(P<0.05),HT22细胞凋亡率、Bax,Cleaved caspase-3水平,LDH漏出率降低(P<0.05); 与sh-circTLK1组比较,sh-circTLK1+miR-424-5p抑制剂组细胞活力降低(P<0.05),HT22细胞凋亡率、Bax,Cleaved caspase-3水平、LDH漏出率升高(P<0.05); 与sh-circTLK1+miR-424-5p抑制剂组比较,sh-circTLK1+miR-424-5p抑制剂+sh FBXO3组细胞活力升高(P<0.05),HT22细胞凋亡率、Bax,Cleaved caspase-3水平、LDH漏出率降低(P<0.05); CircTLK1与miR-424-5p以及miR-424-5p与FBXO3均存在靶向关系。结论 CircTLK1沉默可能通过调控miR-424-5p/FBXO3对OGD/R诱导的HT22细胞损伤来发挥保护作用。     

Protective action of B1R antagonist against cerebral ischemia-reperfusion injury through suppressing miR-200c expression of Microglia-derived microvesicles

Background and objective: Cerebral ischemia–reperfusion (I/R) injury is a common side-effect for cerebral ischemic disease and its therapeutic regimen is limited. Kinin is pro-inflammatory peptide that is released and acts at the site of injury and inflammation such as brain and it works through bradykinin 1 receptor (B1R). The present study was to examine the effect of B1R antagonist on cerebral I/R injury and the potential mechanism.

Methods: Cerebral I/R injury was induced in mice by transient middle cerebral artery occlusion (MCAO). Neurological function was assessed by Bederson score. Infarct volumes were measured using planimetry. In vitro cell model was made by oxygen-glucose deprivation-Hypoxia/Reoxygenation (OGD-H/R) treatment to N9 microglia cell; and the cultured medium was collected for microvesicles (MVs) isolation and subsequent co-cultured with HT22 cell for sake of assessing their function on neural cell. Relative expression of miR-200c was determined by real time quantitative PCR. Dual luciferase reporter assay was performed to detect the regulatory function of miR-200c to syntaxin-1A.

Results: R715 (B1R antagonist) treatment (500 μg/kg) improves neurologic function after cerebral I/R injury indicated by the decrease of Bederson score and infarct volume. MVs from OGD-H/R treated-N9 cell attenuated neural HT22 cell viability, treatment with LDBK (B1R agonist) accelerated the suppression of HT22 resulted from OGD-H/R; whereas this attenuation was partly weakened by B1R antagonist pretreatment (100 nmol/L). At the same time, B1R antagonist pretreatment caused downregulation of miR-200c in N9 cell and N9-derived MVs, and contributed to syntaxin-1A over expression in HT22 cell. Result of luciferase reporter assay suggested that miR-200c can regulate syntaxin-1A expression. MVs from miR-200c knockdown N9 cells medium had the same effect of B1R antagonist that caused the upregulation of syntaxin-1A and improved OGD-H/R-induced reduction of HT22 cell viability.

Conclusion: Our data suggested that blockage of B1R by B1R antagonist provides neuroprotection action through suppressing signaling delivery of microglia-MVs-miR-200c to neural cell.     

糖尿病小鼠加重脑缺血后认知障碍的相关机制研究

目的探讨氧化应激损伤对糖尿病小鼠局灶性脑缺血后认知功能的影响。方法制备糖尿病模型,参照Longa等方法制成大鼠局灶性大脑中动脉阻断(MCAO)模型,采用Longa法进行神经功能缺失评分,苏木精-伊红染色测定梗死体积,Western blotting法检测Nrf2/HO-1及认知相关性蛋白p-Ca MKII/Ca MKII、p-Synapain/Synapain、p-Glu R1/Glu R1的蛋白表达。结果糖尿病小鼠局灶性脑缺血-再灌注后神经功能缺失评分、梗死体积较非糖尿病组明显严重(P0.05),同时伴有脑组织Nrf2/HO-1、p-Ca MKII/Ca MKII、p-Synapain/Synapain、p-Glu R1/Glu R1蛋白表达下调(P0.05)。结论糖尿病小鼠局灶性脑缺血—再灌注后Nrf2/HO-1表达降低,且与神经功能缺失及p-Ca MKII/Ca MKII、p-Synapain/Synapain、p-Glu R1/Glu R1表达下调一致,提示Nrf2/HO-1是糖尿病脑梗死后导致认知障碍的关键环节。     

Exosomes containing miR-451a is involved in the protective effect of cerebral ischemic preconditioning against cerebral ischemia and reperfusion injury

AimTo study the role of exosomes in the protective effect of cerebral ischemic preconditioning (cerebral‐IPC) against cerebral I/R injury.MethodMouse models of cerebral‐IPC and MCAO/R were established as described previously, and their behavioral, pathological, and proteomic changes were analyzed. Neuro‐2a subjected to OGD/R were treated with exosomes isolated from the plasma of sham‐operated and cerebral‐IPC mice. The differentially expressed miRNAs between exosomes derived from sham‐operated (S‐exosomes) and preconditioned (IPC‐exosomes) mice were identified through miRNA array, and their targets were identified through database search. The control and OGD/R cells were treated with the IPC‐exosomes, miRNA mimic or target protein inhibitor, and their viability, oxidative, stress and apoptosis rates were measured. The activated pathways were identified by analyzing the levels of relevant proteins.ResultsCerebral‐IPC mitigated the cerebral injury following ischemia and reperfusion, and increased the number of plasma exosomes. IPC‐exosomes increased the survival of Neuro‐2a cells after OGD/R. The miR‐451a targeting Rac1 was upregulated in the IPC‐exosomes relative to S‐exosomes. The miR‐451a mimic and the Rac1 inhibitor NSC23766 reversed OGD/R‐mediated activation of Rac1 and its downstream pathways.ConclusionCerebral‐IPC ameliorated cerebral I/R injury by inducing the release of exosomes containing miR‐451a.     

丁苯酞预处理对大鼠脑缺血再灌注损伤的神经保护作用

目的研究丁苯酞预处理对大鼠局灶性脑缺血再灌注损伤的神经保护作用。方法健康成年SD雄性大鼠48只,随机分为假手术组、缺血再灌注组、丁苯酞预处理组,每组各16只。各组均灌胃5d后,采用线栓法制作大鼠局灶性脑缺血再灌注(MCAO)模型,缺血2h、再灌注24h,进行神经功能缺损评分,TTC染色及图像分析观察脑梗死体积,免疫组化法检测脑组织caspase-3、bcl-2表达的变化。结果与缺血再灌注组相比,丁苯酞预处理组神经缺损程度改善,梗死灶体积减少,caspase-3阳性细胞数量减少,bcl-2表达上调。结论丁苯酞可减轻缺血性脑血管病的发作,具有一定的神经保护作用。     

敲低miR-103b对氧葡萄糖剥夺/复氧诱导的神经元损伤的保护作用研究

目的 神经元损伤是脑梗死(cerebral infarction,CI)疾病发生发展的关键因素.微小RNA(miRNAs)在神经功能恢复中起主要作用.本研究旨在探讨miR-103b对人皮质神经元细胞(human cortical neuron,HCN)细胞增殖和凋亡的调节作用和机制.方法 HCN暴露于氧葡萄糖剥夺/复氧...