IcarisideⅡ alleviates oxygen-glucose deprivation and reoxygenation-induced PC12 celloxidative injury by activating Nrf2 / SIRT3signaling pathway

OBJECTIVE To investigate icariside(ICS)Ⅱ protects against PC12 cel damage induced by oxygen-glucose deprivation and reoxygenation and explore its mechanism.METHODS The oxidative stress injury model was induced by oxygen-glucose deprivation/reoxygenation(OGD/R) 2 h/24 h in PC12 cells.N-acetyl-lcysteine(NAC),a classical anti-oxidant,was used as positive control.Pharmacodynamic experimental study groups as follows:control,control+ICS Ⅱ50 μmol·L^(-1),OGD/R,OGD/R+ICSⅡ 12.5 μmol·L^(-1),OGD/R + ICS Ⅱ 25 μmol·L^(-1),OGD/R + ICS Ⅱ50 μmol·L^(-1),and OGD/R+NAC 100 μmol·L^(-1) groups.Cell viability and lactate dehydrogenase(LDH) leakage rate were measured by MTT assay and LDH ELISA kit,respectively.Moreover,reactive oxygen species(ROS) ELISA kit was used for detection of intracellular ROS generation,Mito-SOX fluorescence staining was used for detecting production of ROS in mitochondria and mitochondrial membrane potential(MMP)was detected by rhodamine 123 dye.In addition,PC12 cells apoptosis was detected by one-step TUNEL assay.Furthermore,the expressions of nuclear factor erythroid 2-related factors(Nrf2),Keap1,HO^(-1),NQO^(-1),silent information regulator 3(SIRT3),IDH2,Bax,Bcl-2 and caspase 3 were detected by Western blotting analysis.RESULTS The results of MTT and LDH assay showed that OGD/R reduced the cell viability and improved LDH release compared with the control or ICSⅡ 50 μmol·L^(-1) alone(P<0.01).Meanwhile,OGD/R not only increased intracellular and mitochondrial ROS generation,but also elevated the fluorescence intensity of TUNEL staining,at the same time,the MMP was declined when challenged by OGD/R.Furthermore,the Western blotting results showed that OGD/R induced the increase in the expression of cytoplasm-Nrf2,Keap1,Bax and cleaved-caspase 3 level,while the decrease in the expression of nucleus-Nrf2,HO^(-1),NQO^(-1),SIRT3,IDH2 and Bcl-2(P<0.05).However,ICS Ⅱ significantly increased the viability of PC12 cells and reduced LDH leakage(P<0.01).Notably,ICS Ⅱ also suppressed ROS generation both in the intracellular and mitochondria,as well as restored MMP.It was also worthy to note that ICS Ⅱ decreased the expressions of cytoplasmNrf2,Keap1,Bax and the level of cleaved-caspase3,whereas,it increased the expressions of nucleus-Nrf2,HO^(-1),NQO^(-1),SIRT3,IDH2 and Bcl-2(P<0.05).CONCLUSION ICSⅡ reduced OGD/Rinduced oxidative damage in PC12 cells under the laboratory conditions,and its underlying mechanism may be related to the regulation of Nrf2/SIRT3 signaling pathway.

Protective mechanisms of micro RNA-27a against oxygen-glucose deprivation-induced injuries in hippocampal neurons

Hypoxic injuries during fetal distress have been shown to cause reduced expression of micro RNA-27a（mi R-27a）,which regulates sensitivity of cortical neurons to apoptosis.We hypothesized that miR-27 a overexpression attenuates hypoxia- and ischemia-induced neuronal apoptosis by regulating FOXO1,an important transcription factor for regulating the oxidative stress response.miR-27 a mimic was transfected into hippocampal neurons to overexpress miR-27 a.Results showed increased hippocampal neuronal viability and decreased caspase-3 expression.The luciferase reporter gene system demonstrated that mi R-27 a directly binded to FOXO1 3′UTR in hippocampal neurons and inhibited FOXO1 expression,suggesting that FOXO1 was the target gene for mi R-27 a.These findings confirm that mi R-27 a protects hippocampal neurons against oxygen-glucose deprivation-induced injuries.The mechanism might be mediated by modulation of FOXO1 and apoptosis-related gene caspase-3 expression.

Rac1 relieves neuronal injury induced by oxygen-glucose deprivation and re-oxygenation via regulation of mitochondrial biogenesis and function

Certain microRNAs(miRNAs)can function as neuroprotective factors after reperfusion/ischemia brain injury.miRNA-142-3p can participate in the occurrence and development of tumors and myocardial ischemic injury by negatively regulating the activity of Rac1,but it remains unclear whether miRNA-142-3p also participates in cerebral ischemia/reperfusion injury.In this study,a model of oxygen-glucose deprivation/re-oxygenation in primary cortical neurons was established and the neurons were transfected with miR-142-3p agomirs or miR-142-3p antagomirs.miR-142-3p expression was down-regulated in neurons when exposed to oxygen-glucose deprivation/re-oxygenation.Over-expression of miR-142-3p using its agomir remarkably promoted cell death and apoptosis induced by oxygen-glucose deprivation/re-oxygenation and improved mitochondrial biogenesis and function,including the expression of peroxisome proliferator-activated receptor-γcoactivator-1α,mitochondrial transcription factor A,and nuclear respiratory factor 1.However,the opposite effects were produced if miR-142-3p was inhibited.Luciferase reporter assays verified that Rac Family Small GTPase 1(Rac1)was a target gene of miR-142-3p.Over-expressed miR-142-3p inhibited NOX2 activity and expression of Rac1 and Rac1-GTPase(its activated form).miR-142-3p antagomirs had opposite effects after oxygen-glucose deprivation/re-oxygenation.Our results indicate that miR-142-3p down-regulates the expression and activation of Rac1,regulates mitochondrial biogenesis and function,and inhibits oxygen-glucose deprivation damage,thus exerting a neuroprotective effect.The experiments were approved by the Committee of Experimental Animal Use and Care of Central South University,China(approval No.201703346)on March 7,2017.

Curcumin pretreatment and post-treatment both improve the antioxidative ability of neurons with oxygen-glucose deprivation

Recent studies have shown that induced expression of endogenous antioxidative enzymes thr- ough activation of the antioxidant response element/nuclear factor erythroid 2-related factor 2 （Nrf2） pathway may be a neuroprotective strategy. In this study, rat cerebral cortical neurons cultured in vitro were pretreated with 10 ktM curcumin or post-treated with 5 pM curcumin, respectively before or after being subjected to oxygen-glucose deprivation and reoxygenation for 24 hours. Both pretreatment and post-treatment resulted in a significant decrease of cell injury as indicated by propidium iodide/Hoechst 33258 staining, a prominent increase of Nrf2 protein expression as indicated by western blot analysis, and a remarkable increase of protein expression and enzyme activity in whole cell lysates of thioredoxin before ischemia, after ischemia, and after reoxygenation. In addition, post-treatment with curcumin inhibited early DNA/RNA oxidation as indicated by immunocytochemistry and increased nuclear Nrf2 protein by inducing nuclear accumulation of Nrf2. These findings suggest that curcumin activates the expression of thi- oredoxin, an antioxidant protein in the Nrf2 pathway, and protects neurons from death caused by oxygen-glucose deprivation in an in vitro model of ischemia/reperfusion. We speculate that pharmacologic stimulation of antioxidant gene expression may be a promising approach to neu- roprotection after cerebral ischemia.

Activin A prevents neuron-like PC12 cell apoptosis after oxygen-glucose deprivation

In this study, PC12 cells were induced to differentiate into neuron-like cells using nerve growth factor, and were subjected to oxygen-glucose deprivation. Cells were treated with 0, 10, 20, 30, 50, 100 ng/mL exogenous Activin A. The 3-（4,5-dimethyl-2-thiazolyl）-2,5-diphenyl tetrazolium bromide assay and Hoechst 33324 staining showed that the survival percentage of PC12 cells significantly decreased and the rate of apoptosis significantly increased after oxygen-glucose deprivation. Exogenous Activin A significantly increased the survival percentage of PC12 cells in a dose-dependent manner. Reverse transcription-PCR results revealed a significant increase in Activin receptor IIA, Smad3 and Smad4 mRNA levels, which are key sites in the Activin A/Smads signaling pathway, in neuron-like cells subjected to oxygen-glucose deprivation, while mRNA expression of the apoptosis-regulation gene caspase-3 decreased. Our experimental findings indicate that exogenous Activin A plays an anti-apoptotic role and protects neurons by means of activating the Activin A/Smads signaling pathway.

Dynamic changes in proprotein convertase 2 activity in cortical neurons after ischemia/reperfusion and oxygen-glucose deprivation

In this study, a rat model of transient focal cerebral ischemia was established by performing 100 minutes of middle cerebral artery occlusion, and an in vitro model of experimental oxygen-glucose deprivation using cultured rat cortical neurons was established. Proprotein convertase 2 activity gradually decreased in the ischemic cortex with increasing duration of reperfusion. In cultured rat cortical neurons, the number of terminal deoxynucleotidyl transferase-mediated 2＇-deoxyuridine 5＇-triphosphate-biotin nick end labeling-positive neurons significantly increased and proprotein convertase 2 activity also decreased gradually with increasing duration of oxygen-glucose deprivation. These experimental findings indicate that proprotein convertase 2 activity decreases in ischemic rat cortex after reperfusion, as well as in cultured rat cortical neurons after oxygen-glucose deprivation. These changes in enzyme activity may play an important pathological role in brain injury.

Expression of hypoxia-inducible factor 1 alpha and oligodendrocyte lineage gene-1 in cultured brain slices after oxygen-glucose deprivation

Oligodendrocyte lineage gene-1 expressed in oligodendrocytes may trigger the repair of neuronal myelin impairment, and play a crucial role in myelin repair. Hypoxia-inducible factor la, a transcription factor, is of great significance in premature infants with hypoxic-ischemic brain damage There is little evidence of direct regulatory effects of hypoxia-inducible factor le on oligodendrocyte lineage gene-l. In this study, brain slices of Sprague-Dawley rats were cultured and subjected to oxygen-glucose deprivation. Then, slices were transfected with hypoxia-inducible factor la or oligodendrocyte lineage gene-1. The expression levels of hypoxia-inducible factor la and oligodendrocyte lineage gene-1 were significantly up-regulated in rat brains prior to transfection, as detected by immunohistochemical staining. Eight hours after transfection of slices with hypoxia-inducible factor la, oligodendrocyte lineage gene-1 expression was upregulated, and reached a peak 24 hours after transfection. Oligodendrocyte lineage gene-1 transfection induced no significant differences in hypoxia-inducible factor la levels in rat brain tissues with oxygen-glucose deprivation. These experimental findings indicate that hypoxia-inducible factor la can regulate oligodendrocyte lineage gene-1 expression in hypoxic brain tissue, thus repairing the neural impairment.

Chlorogenic acid alleviates hypoxic-ischemic brain injury in neonatal mice

Recent studies have shown that chlorogenic acid(CGA),which is present in coffee,has protective effects on the nervous system.However,its role in neonatal hypoxic-ischemic brain injury remains unclear.In this study,we established a newborn mouse model of hypoxic-ischemic brain injury using a modified Rice-Vannucci method and performed intraperitoneal injection of CGA.We found that CGA intervention effectively reduced the volume of cerebral infarct,alleviated cerebral edema,restored brain tissue structure after injury,and promoted axon growth in injured brain tissue.Moreover,CGA pretreatment alleviated oxygen-glucose deprivation damage of primary neurons and promoted neuron survival.In addition,changes in ferroptosis-related proteins caused by hypoxic-ischemic brain injury were partially reversed by CGA.Furthermore,CGA intervention upregulated the expression of the key ferroptosis factor glutathione peroxidase 4 and its upstream glutamate/cystine antiporter related factors SLC7A11 and SLC3A2.In summary,our findings reveal that CGA alleviates hypoxic-ischemic brain injury in neonatal mice by reducing ferroptosis,providing new ideas for the treatment of neonatal hypoxic-ischemic brain injury.

Upregulation of CDGSH iron sulfur domain 2 attenuates cerebral ischemia/reperfusion injury

CDGSH iron sulfur domain 2 can inhibit ferroptosis,which has been associated with cerebral ischemia/reperfusion,in individuals with head and neck cancer.Therefore,CDGSH iron sulfur domain 2 may be implicated in cerebral ischemia/reperfusion injury.To validate this hypothesis in the present study,we established mouse models of occlusion of the middle cerebral artery and HT22 cell models of oxygen-glucose deprivation and reoxygenation to mimic cerebral ischemia/reperfusion injury in vivo and in vitro,respectively.We found remarkably decreased CDGSH iron sulfur domain 2 expression in the mouse brain tissue and HT22 cells.When we used adeno-associated virus and plasmid to up-regulate CDGSH iron sulfur domain 2 expression in the brain tissue and HT22 cell models separately,mouse neurological dysfunction was greatly improved;the cerebral infarct volume was reduced;the survival rate of HT22 cells was increased;HT22 cell injury was alleviated;the expression of ferroptosis-related glutathione peroxidase 4,cystine-glutamate antiporter,and glutathione was increased;the levels of malondialdehyde,iron ions,and the expression of transferrin receptor 1 were decreased;and the expression of nuclear-factor E2-related factor 2/heme oxygenase 1 was increased.Inhibition of CDGSH iron sulfur domain 2 upregulation via the nuclear-factor E2-related factor 2 inhibitor ML385 in oxygen-glucose deprived and reoxygenated HT22 cells blocked the neuroprotective effects of CDGSH iron sulfur domain 2 up-regulation and the activation of the nuclear-factor E2-related factor 2/heme oxygenase 1 pathway.Our data indicate that the up-regulation of CDGSH iron sulfur domain 2 can attenuate cerebral ischemia/reperfusion injury,thus providing theoretical support from the perspectives of cytology and experimental zoology for the use of this protein as a therapeutic target in patients with cerebral ischemia/reperfusion injury.

miRNA-21-5p is an important contributor to the promotion of injured peripheral nerve regeneration using hypoxia-pretreated bone marrow-derived neural crest cells

Our previous study found that rat bone marrow–derived neural crest cells(acting as Schwann cell progenitors)have the potential to promote long-distance nerve repair.Cell-based therapy can enhance peripheral nerve repair and regeneration through paracrine bioactive factors and intercellular communication.Nevertheless,the complex contributions of various types of soluble cytokines and extracellular vesicle cargos to the secretome remain unclear.To investigate the role of the secretome and extracellular vesicles in repairing damaged peripheral nerves,we collected conditioned culture medium from hypoxia-pretreated neural crest cells,and found that it significantly promoted the repair of sensory neurons damaged by oxygen-glucose deprivation.The mRNA expression of trophic factors was highly expressed in hypoxia-pretreated neural crest cells.We performed RNA sequencing and bioinformatics analysis and found that miR-21-5p was enriched in hypoxia-pretreated extracellular vesicles of neural crest cells.Subsequently,to further clarify the role of hypoxia-pretreated neural crest cell extracellular vesicles rich in miR-21-5p in axonal growth and regeneration of sensory neurons,we used a microfluidic axonal dissociation model of sensory neurons in vitro,and found that hypoxia-pretreated neural crest cell extracellular vesicles promoted axonal growth and regeneration of sensory neurons,which was greatly dependent on loaded miR-21-5p.Finally,we constructed a miR-21-5p-loaded neural conduit to repair the sciatic nerve defect in rats and found that the motor and sensory functions of injured rat hind limb,as well as muscle tissue morphology of the hind limbs,were obviously restored.These findings suggest that hypoxia-pretreated neural crest extracellular vesicles are natural nanoparticles rich in miRNA-21-5p.miRNA-21-5p is one of the main contributors to promoting nerve regeneration by the neural crest cell secretome.This helps to explain the mechanism of action of the secretome and extracellular vesicles of neural crest cells in repairing damaged peripheral nerves,and also promotes the application of miR-21-5p in tissue engineering regeneration medicine.

Transplantation of human placental chorionic plate-derived mesenchymal stem cells for repair of neurological damage in neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic-ischemic encephalopathy is often associated with permanent cerebral palsy,neurosensory impairments,and cognitive deficits,and there is no effective treatment for complications related to hypoxic-ischemic encephalopathy.The therapeutic potential of human placental chorionic plate-derived mesenchymal stem cells for various diseases has been explored.However,the potential use of human placental chorionic plate-derived mesenchymal stem cells for the treatment of neonatal hypoxic-ischemic encephalopathy has not yet been investigated.In this study,we injected human placental chorionic plate-derived mesenchymal stem cells into the lateral ventricle of a neonatal hypoxic-ischemic encephalopathy rat model and observed significant improvements in both cognitive and motor function.Protein chip analysis showed that interleukin-3 expression was significantly elevated in neonatal hypoxic-ischemic encephalopathy model rats.Following transplantation of human placental chorionic plate-derived mesenchymal stem cells,interleukin-3 expression was downregulated.To further investigate the role of interleukin-3 in neonatal hypoxic-ischemic encephalopathy,we established an in vitro SH-SY5Y cell model of hypoxic-ischemic injury through oxygen-glucose deprivation and silenced interleukin-3 expression using small interfering RNA.We found that the activity and proliferation of SH-SY5Y cells subjected to oxygen-glucose deprivation were further suppressed by interleukin-3 knockdown.Furthermore,interleukin-3 knockout exacerbated neuronal damage and cognitive and motor function impairment in rat models of hypoxic-ischemic encephalopathy.The findings suggest that transplantation of hpcMSCs ameliorated behavioral impairments in a rat model of hypoxic-ischemic encephalopathy,and this effect was mediated by interleukin-3-dependent neurological function.

基于pgrmc1调控的黄体酮抑制氧糖剥夺/复氧新生小鼠神经元损伤机制分析

目的 基于黄体酮膜受体组件1(pgrmc1)调控,探讨黄体酮抑制氧糖剥夺/复氧(OGD/R)新生小鼠神经元损伤的作用机制。方法 选用出生12 h内的新生小鼠分离原代皮层神经元细胞,体外培养7 d,利用微管相关蛋白2检测进行鉴定后,随机分为对照组、二甲基亚砜(DMSO)组、AG205组、黄体酮组、AG205+黄体酮组。DMSO组、AG205组、黄体酮组、AG205+黄体酮组加入制备好的缺糖D-Hanks液、置于缺氧培养箱中培养2 h,换为神经元生长培养基;DMSO组在造模前1 h给予DMSO预处理,AG205组和AG205+黄体酮组在造模前1 h给予AG205(pgrmc1拮抗剂)10μmol/L预处理,黄体酮组和AG205+黄体酮组于造模后2 h给予黄体酮20μmol/L。复氧24 h后,采用CCK-8法检测细胞活力,流式细胞术检测凋亡细胞。结果 DMSO组、AG205组细胞存活率低于对照组,AG205组低于DMSO组;黄体酮组、AG205+黄体酮组细胞存活率高于AG205组,黄体酮组高于AG205+黄体酮组(P均<0.05)。DMSO组、AG205组细胞凋亡率高于对照组,AG205组高于DMSO组,黄体酮组、AG205+黄体酮组细胞凋亡率低于AG205组(P均<0.05)。结论 黄体酮可抑制OGD/R新生小鼠神经元损伤,抑制pgrmc1可降低OGD/R神经元活力、增加细胞凋亡,黄体酮抑制OGD/R神经元损伤的作用可能与调控pgrmc1有关。

Neuroprotective effect of penehyclidine hydrochloride on focal cerebral ischemia-reperfusion injury

Penehyclidine hydrochloride can promote microcirculation and reduce vascular permeability. However, the role of penehyclidine hydrochlodde in cerebral ischemia-reperfusion injury remains unclear. In this study, in vivo middle cerebral artery occlusion models were established in experimental rats, and penehyclidine hydrochloride pretreatment was given via intravenous injection prior to model establishment. Tetrazolium chloride, terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling and immunohistochemical staining showed that, penehyclidine hydrochloride pretreatment markedly attenuated neuronal histopathological changes in the cortex, hippocampus and striatum, reduced infarction size, increased the expression level of BcI-2, decreased the expression level of caspase-3, and inhibited neuronal apoptosis in rats with cerebral ischemia-reperfusion injury. Xanthine oxidase and thiobarbituric acid chromogenic results showed that penehyclidine hydrochloride upregulated the activity of superoxide dismutase and downregulated the concentration of malondialdehyde in the ischemic cerebral cortex and hippocampus, as well as reduced the concentration of extracellular excitatory amino acids in rats with cerebral ischemia-reperfusion injury. In addition, penehyclidine hydrochloride inhibited the expression level of the NR1 subunit in hippocampal nerve cells in vitro following oxygen-glucose deprivation, as detected by PCR. Experimental findings indicate that penehyclidine hydrochloride attenuates neuronal apoptosis and oxidative stress injury after focal cerebral ischemia-reperfusion, thus exerting a neuroprotective effect.

Essential role of MALAT1 in reducing traumatic brain injury

As a highly evolutionary conserved long non-coding RNA,metastasis associated lung adenocarcinoma transcript 1(MALAT1)was first demonstrated to be related to lung tumor metastasis by promoting angiogenesis.To investigate the role of MALAT1 in traumatic brain injury,we established mouse models of controlled cortical impact and cell models of oxygen-glucose deprivation to mimic traumatic brain injury in vitro and in vivo.The results revealed that MALAT1 silencing in vitro inhibited endothelial cell viability and tube formation but increased migration.In MALAT1-deficient mice,endothelial cell proliferation in the injured cortex,functional vessel density and cerebral blood flow were reduced.Bioinformatic analyses and RNA pull-down assays validated enhancer of zeste homolog 2(EZH2)as a downstream factor of MALAT1 in endothelial cells.Jagged-1,the Notch homolog 1(NOTCH1)agonist,reversed the MALAT1 deficiency-mediated impairment of angiogenesis.Taken together,our results suggest that MALAT1 controls the key processes of angiogenesis following traumatic brain injury in an EZH2/NOTCH1-dependent manner.

Inhibition of inflammatory mediator release from microglia can treat ischemic/hypoxic brain injury

Interleukin-1α and interleukin-1β aggravate neuronal injury by mediating the inf1αmmatory reaction following ischemic/hypoxic brain injury. It remains unclear whether interleukin-1α and interleukin-1β are released by microglia or astrocytes. This study prepared hippocampal slices that were subsequently subjected to oxygen and glucose deprivation. Hematoxylin-eosin staining verified that neurons exhibited hypoxic changes. Results of enzyme-linked immunosorbent assay found that interleukin-1α and interleukin-1β participated in this hypoxic process. Moreover, when hypoxic injury occurred in the hippocampus, the release of interleukin-1α and interleukin-1β was mediated by the P2X4 receptor and P2X7 receptor. Immunofluorescence staining revealed that during ischemia/hypoxia, the P2X4 receptor, P2X7 receptor, interleukin-1α and interleukin-1β expression was detectable in rat hippocampal microglia, but only P2X4 receptor and P2X7 receptor expression was detected in astrocytes. Results suggested that the P2X4 receptor and P2X7 receptor, respectively, mediated interleukin-1α and interleukin-1β released by microglia, resulting in hippocampal ischemic/hypoxic injury. Astrocytes were activated, but did not synthesize or release interleukin-1α and interleukin-1β.

Silencing miRNA-324-3p protects against cerebral ischemic injury via regulation of the GATA2/A1R axis

Previous studies have suggested that miR-324-3p is related to the pathophysiology of cerebral ischemia,but the mechanism underlying this relationship is unclea r.In this study,we found that miR-324-3p expression was decreased in patients with acute ischemic stroke and in in vitro and in vivo models of ischemic stro ke.miR-324-3p agomir potentiated ischemic brain damage in rats subjected to middle cerebral artery occlusion,as indicated by increased infarct volumes and cell apoptosis rates and greater neurological deficits.In a PC12 cell oxygen-glucose deprivation/reoxygenation model,a miR-324-3 p mimic decreased cell viability and expression of the anti-apoptotic protein BCL2 and increased expression of the pro-apoptotic protein BAX and rates of cell apoptosis,whereas treatment with a miR-324-3p inhibitor had the opposite effects.Silencing miR-324-3p increased adenosine A1 receptor(A1R)expression thro ugh regulation of GATA binding protein 2(GATA2).These findings suggest that silencing miR-324-3p reduces ischemic brain damage via the GATA2/A1R axis.

Krüppel-like factor 7 attenuates hippocampal neuronal injury after traumatic brain injury

Our previous study has shown that the transcription factor Krüppel-like factor 7(KLF7) promotes peripheral nerve regeneration and motor function recovery after spinal cord injury.KLF7 also participates in traumatic brain injury,but its regulatory mechanisms remain poorly understood.In the present study,an HT22 cell model of traumatic brain injury was established by stretch injury and oxygenglucose deprivation.These cells were then transfected with an adeno-associated virus carrying KLF7(AAV-KLF7).The results revealed that,after stretch injury and oxygen-glucose deprivation,KLF7 greatly reduced apoptosis,activated caspase-3 and lactate dehydrogenase,downregulated the expression of the apoptotic markers B-cell lymphoma 2(Bcl-2)-associated X protein(Bax) and cleaved caspase-3,and increased the expression of βIII-tubulin and the antiapoptotic marker Bcl-2.Furthermore,KLF7 overexpression upregulated Janus kinase 2(JAK2) and signal transducer and activator of transcription 3(STAT3) phosphorylation in HT22 cells treated by stretch injury and oxygenglucose deprivation.Immunoprecipitation assays revealed that KLF7 directly participated in the phosphorylation of STAT3.In addition,treatment with AG490,a selective inhibitor of JAK2/STAT3,weakened the protective effects of KLF7.A mouse controlled cortical impact model of traumatic brain injury was then established.At 30 minutes before modeling,AAV-KLF7 was injected into the ipsilateral lateral ventricle.The protein and m RNA levels of KLF7 in the hippocampus were increased at 1 day after injury and recovered to normal levels at 3 days after injury.KLF7 reduced ipsilateral hippocampal atrophy,decreased the injured cortex volume,downregulated Bax and cleaved caspase-3 expression,and increased the number of 5-bromo-2'-deoxyuridine-positive neurons and Bcl-2 protein expression.Moreover,KLF7 transfection greatly enhanced the phosphorylation of JAK2 and STAT3 in the ipsilateral hippocampus.These results suggest that KLF7 may protect hippocampal neurons after traumatic brain injury through activation of the JAK2/STAT3 signaling pathway.The study was approved by the Institutional Review Board of Mudanjiang Medical University,China(approval No.mdjyxy-2018-0012) on March 6,2018.

构建基于脱水的对比剂肾病大鼠模型

目的建立对比剂肾病(CIN)动物模型,通过肾功能检测判断模型构建成功,为CIN研究提供模型构建依据。方法选择SPF级7~8周龄的雄性SD大鼠为实验对象,正常饲养1周后,取健康雄性SD大鼠24只,用于药物诱导建立急性肾损伤大鼠模型。将24只大鼠随机分为A组(空白对照组)、B组(CIN组)、C组[对比剂(CM)组],每组8只。对A、B、C组大鼠禁水48 h后,分别静脉注射10 mL/kg生理盐水、消炎痛(吲哚美辛)+N-硝基-L-精氨酸甲酯+CM、CM,检测各组大鼠各时间点肾损伤标志物[血清肌酐(Scr)、尿素氮(BUN)、胱抑素C(Cys C)]并比较其变化。结果A组大鼠在干预后72 h内检测Scr、BUN、Cys C水平与同组0 h比较,差异均无统计学意义(P>0.05),而C组大鼠干预后24、48 h Scr水平较同组0 h显著升高,差异均有统计学意义(P<0.05),但B组干预后24 h Scr水平较同组0 h升高更加明显,差异有统计学意义(P<0.05)。B、C组大鼠干预后24 hBUN水平均高于同组0 h,差异均有统计学意义(P<0.05)。B、C组大鼠干预后24 h Scr水平均超过同组0 h的50%,而B组大鼠干预后24、48 h Scr水平较C组升高,差异均有统计学意义(P<0.05)。结论利用综合指标分析评估,建立了一种新的基于脱水和碘普罗胺暴露的CIN大鼠模型,并验证了该模型有助于了解CIN。

碘普罗胺联合禁水建立造影剂肾病大鼠模型及细胞凋亡表现

目的建立造影剂直接肾脏损伤的动物模型,通过综合指标判断模型成功,为造影剂肾病研究提供模型借鉴。方法对SD大鼠行禁水联合静脉给予含碘造影剂,通过检测肾损伤标志物变化,同时观察肾组织形态学及细胞凋亡改变得到较好的疾病表型。结果单纯禁水组在恢复饮水24h后检测肌酐、尿素氮水平几乎恢复基线值,而禁水联合造影剂组术后血清肌酐可观察到明显升高(54.45±14.39μmol/L vs.28.26±9.98μmol/L;P<0.01),尿素氮水平也持续升高(34.70±2.66μmol/L vs.10.75±5.45μmol/L;P<0.001)。HE染色提示造影剂肾病建模组组织受损主要集中在肾皮髓交界、外髓内带的近端小管;表现为小管上皮细胞空泡样变性,细胞扁平萎缩或坏死脱落,损伤评分差异显著(2.0±0.82 vs.0.46±0.49;P=0.02)。同时凋亡蛋白Bax在e组(禁水+造影剂)(P=0.02)及f组(禁水+速尿+造影剂)较对照组表达明显升高(P=0.015);TUNEL法检测细胞凋亡率在e组(16.2±5.2%vs.5.1±1.3%;P<0.01)及f组较对照组均明显增加(20.8±8.7%vs.5.1±1.3%;P<0.001)。结论利用综合指标分析评估,直接造影剂接触联合禁水预处理方法能稳定的建立造影剂肾病模型。

失笑散降低氧糖剥夺再灌注BV2细胞损伤及NLRP3的表达

目的:研究失笑散对BV2细胞氧糖剥夺再灌注(OGD/R)模型的保护作用及潜在机制。方法:将BV2细胞分为对照组,模型(OGD/R)组及失笑散组。失笑散组用不同浓度(1、10、20、50、100μg/mL)预处理BV2细胞2 h。对照组正常培养,不给药,不进行糖氧剥夺(OGD);模型组不给药,与失笑散组同时进行OGD,缺氧结束后再灌注24 h,收集细胞及其上清液。CCK-8法检测BV2细胞的活力;流式细胞术检测BV2细胞的凋亡;实时定量PCR和ELISA分别检测BV2细胞TNF-α、IL-6和NLRP3及相关蛋白Caspase-1、IL-1β、IL-18的mRNA和蛋白表达。结果:不同浓度失笑散并不影响BV2细胞活力。与对照组比较,模型组BV2细胞凋亡显著增多(P<0.01),而高浓度失笑散明显减少BV2细胞凋亡(P<0.05)。实时定量PCR和ELISA结果表明,与模型组比较,失笑散观察组BV2细胞TNF-α、IL-6和NLRP3炎性小体及相关蛋白Caspase-1、IL-1β、IL-18的mRNA和蛋白表达量明显减少(P<0.05)。结论:失笑散减轻OGD/R对BV2细胞的损伤及降低炎症介质的表达,机制可能与调控NLRP3炎性小体介导的炎症信号通路有关。