Resatorvid protects against hypoxic-ischemic brain damage in neonatal rats

Secondary brain damage caused by hyperactivation of autophagy and inflammatory responses in neurons plays an important role in hypoxic-ischemic brain damage(HIBD).Although previous studies have implicated Toll-like receptor 4(TLR4)and nuclear factor kappa-B(NF-κB)in the neuroinflammatory response elicited by brain injury,the role and mechanisms of the TLR4-mediated autophagy signaling pathway in neonatal HIBD are still unclear.We hypothesized that this pathway can regulate brain damage by modulating neuron autophagy and neuroinflammation in neonatal rats with HIBD.Hence,we established a neonatal HIBD rat model using the Rice-Vannucci method,and injected 0.75,1.5,or 3 mg/kg of the TLR4 inhibitor resatorvid(TAK-242)30 minutes after hypoxic ischemia.Our results indicate that administering TAK-242 to neonatal rats after HIBD could significantly reduce the infarct volume and the extent of cerebral edema,alleviate neuronal damage and neurobehavioral impairment,and decrease the expression levels of TLR4,phospho-NF-κB p65,Beclin-1,microtubule-associated protein l light chain 3,tumor necrosis factor-α,and interleukin-1βin the hippocampus.Thus,TAK-242 appears to exert a neuroprotective effect after HIBD by inhibiting activation of autophagy and the release of inflammatory cytokines via inhibition of the TLR4/NF-κB signaling pathway.This study was approved by the Laboratory Animal Ethics Committee of Affiliated Hospital of Yangzhou University,China(approval No.20180114-15)on January 14,2018.

Hyperbaric oxygen treatment promotes neural stem cell proliferation in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage

Hyperbaric oxygen therapy for the treatment of neonatal hypoxic-ischemic brain damage has been used clinically for many years, but its effectiveness remains controversial. In addition, the mechanism of this potential neuroprotective effect remains unclear. This study aimed to investigate the influence of hyperbaric oxygen on the proliferation of neural stem cells in the subventricular zone of neonatal Sprague-Dawley rats （7 days old） subjected to hypoxic-ischemic brain damage. Six hours after modeling, rats were treated with hyperbaric oxygen once daily for 7 days. Immunohistochemistry revealed that the number of 5-bromo-2＇-deoxyuridine positive and nestin positive cells in the subventricular zone of neonatal rats increased at day 3 after hypoxic-ischemic brain damage and peaked at day 5. After hyperbaric oxygen treatment, the number of 5-bromo-2＇- deoxyuddine positive and nestin positive cells began to increase at day 1, and was significantly higher than that in normal rats and model rats until day 21. Hematoxylin-eosin staining showed that hyperbaric oxygen treatment could attenuate pathological changes to brain tissue in neonatal rats, and reduce the number of degenerating and necrotic nerve cells. Our experimental findings indicate that hyperbaric oxygen treatment enhances the proliferation of neural stem cells in the subventricular zone of neonatal rats with hypoxic-ischemic brain damage, and has therapeutic potential for promoting neurological recovery following brain injury.

The role of pineal microRNA-325 in regulating circadian rhythms after neonatal hypoxic-ischemic brain damage

Circadian rhythm disorder is a common,but often neglected,consequence of neonatal hypoxic-ischemic brain damage(HIBD).However,the underlying molecular mechanisms remain largely unknown.We previously showed that,in a rat model of HIBD,up-regulation of microRNA-325(miR-325)in the pineal gland is responsible for the suppression of Aanat,a key enzyme involved in melatonin synthesis and circadian rhythm regulation.To better understand the mechanism by which miR-325 affects circadian rhythms in neonates with HIBD,we compared clinical samples from neonates with HIBD and samples from healthy neonates recruited from the First Affiliated Hospital of Soochow University(Dushuhu Branch)in 2019.We found that circulating miR-325 levels correlated positively with the severity of sleep and circadian rhythm disorders in neonates with HIBD.Furthermore,a luciferase reporter gene assay revealed that LIM homeobox 3(LHX3)is a novel downstream target of miR-325.In addition,in miR-325 knock-down mice,the transcription factor LHX3 exhibited an miR-325-dependent circadian pattern of expression in the pineal gland.We established a neonatal mouse model of HIBD by performing doublelayer ligation of the left common carotid artery and exposing the pups to a low-oxygen environment for 2 hours.Lhx3 mRNA expression was significantly down-regulated in these mice and partially rescued in miR-325 knockout mice subjected to the same conditions.Finally,we showed that improvement in circadian rhythm-related behaviors in animals with HIBD was dependent on both miR-325 and LHX3.Taken together,our findings suggest that the miR-325-LHX3 axis is responsible for regulating circadian rhythms and provide novel insights into the identification of potential therapeutic targets for circadian rhythm disorders in patients with neonatal HIBD.The clinical trial was approved by Institutional Review Board of Children’s Hospital of Soochow University(approval No.2015028)on July 20,2015.Animal experiments were approved by Animal Care and Use Committee,School of Medicine,Soochow University,China(approval No.XD-2016-1)on January 15,2016.

Effects of ephedrine on expression of Nogo-A and synaptophysin in neonatal rats following hypoxic-ischemic brain damage

BACKGROUND： Central nervous system axons regenerate poorly following neonatal hypoxic-ischemic brain damage （HIBD）, partly due to inhibitors, such as Nogo-A. Very few studies have addressed the regulation of Nogo-A in neonatal rats following HIBD. However, numerous studies have shown that ephedrine accelerates neuronal remodeling and promotes recovery of neural function in neonatal rats following HIBD. OBJECTIVE： To investigate the effects of ephedrine on expression of Nogo-A and synaptophysin in brain tissues of neonatal rats following HIBD. DESIGN, TIME AND SETTING： A completely randomized, controlled study was performed at the Immunohistochemistry Laboratory of the Research Institute of Pediatrics, Children＇s Hospital of Chongqing Medical University from August 2008 to March 2009. MATERIALS： Ephedrine hydrochloride （Chifeng Pharmaceutical Group, China）, rabbit anti-Nogo-A polyclonal antibody （Abcam, UK）, and rabbit anti-synaptophysin polyclonal antibody （Lab Vision, USA） were used in this study. METHODS： A total of 96 healthy, neonatal, Sprague Dawley rats were randomly assigned to three groups （n = 32）： sham operation, HIBD, and ephedrine. The HIBD model was established by permanent occlusion of the left common carotid artery, followed by 2 hours of hypoxia （8% oxygen and 92% nitrogen）. In the sham operation group, the left common carotid artery was exposed, but was not ligated or subjected to hypoxia. Rats in the ephedrine group were intraperitoneally injected with ephedrine immediately following HIBD, with 1.5 mg/kg each time. Rats in the sham operation and HIBD groups were injected with an equal volume of saline. All neonatal rats were treated once daily for 7 days. MAIN OUTCOME MEASURES： Histopathological damage to the cortex and hippocampus was determined by hematoxylin-eosin staining. Expression of Nogo-A and synaptophysin was detected using immunohistochemical staining. RESULTS： Neuronal degeneration and edema were observed in the hypoxJc-Jschemic cortex and hippocampus by hematoxylin-eosin staining. Compared with the sham operation group, the levels of Nogo-A significantly increased in the HIBD group at various time points （P 〈 0.01）. Nogo-A expression was significantly reduced in the ephedrine group compared with the HIBD group （P 〈 0.01）. Synaptophysin expression was significantly decreased in the hypoxic-ischemJc cortex, compared with the sham operation group （P 〈 0.01）. Synaptophysin levels were significantly increased in the ephedrine group, compared with the HIBD group （P 〈 0.01）. CONCLUSION： Altered Nogo-A expression was associated with inversely altered synaptophysin expression. The use of ephedrine normalized expression levels of Nogo-A and synaptophysin following HIBD.

Protective effects on acute hypoxic-ischemic brain damage in mfat-1 transgenic mice by alleviating neuroinflammation

Acute hypoxic-ischemic brain damage(HIBD)mainly occurs in adults as a result of perioperative cardiac arrest and asphyxia.The benefits of n-3 polyunsaturated fatty acids(n-3 PUFAs)in maintaining brain growth and development are well documented.However,possible protective targets and underlying mechanisms of mfat-1 mice on HIBD require further investigation.The mfat-1 transgenic mice exhibited protective effects on HIBD,as indicated by reduced infarct range and improved neurobehavioral defects.RNA-seq analysis showed that multiple pathways and targets were involved in this process,with the anti-inflammatory pathway as the most significant.This study has shown for the first time that mfat-1 has protective effects on HIBD in mice.Activation of a G protein-coupled receptor 120(GPR120)-related anti-inflammatory pathway may be associated with perioperative and postoperative complications,thus innovating clinical intervention strategy may potentially benefit patients with HIBD.

Estrogen inhibits lipid peroxidation after hypoxic-ischemic brain damage in neonatal rats

Sprague-Dawley neonatal rats within 7 days after birth were used in this study. The left common carotid artery was occluded and rats were housed in an 8% O2 environment for 2 hours to establish a hypoxic-ischemic brain damage model. 17β-estradiol （1 × 10-5 M） was injected into the rat abdominal cavity after the model was successfully established. The left hemisphere was obtained at 12, 24, 48, 72 hours after operation. Results showed that malondialdehyde content in the left brain of neonatal rats gradually increased as modeling time prolonged, while malondialdehyde content of 17β-estrodial-treated rats significantly declined by 24 hours, reached lowest levels at 48 hours, and then peaked at 72 hours after injury. Nicotinamide-adenine dinucleotide phosphate histochemical staining showed the nitric oxide synthase-positive cells and fibers dyed blue/violet and were mainly distributed in the cortex, hippocampus and medial septal nuclei. The number of nitric oxide synthase-positive cells peaked at 48 hours and significantly decreased after 17β-estrodial treatment. Our experimental findings indicate that estrogen plays a protective role following hypoxic-ischemic brain damage by alleviating lipid peroxidation through reducing the expression of nitric oxide synthase and the content of malondialdehyde.

Flunarizine and lamotrigine prophylaxis effects on neuron-specific enolase, S-100, and brain-specific creatine kinase in a fetal rat model of hypoxic-ischemic brain damage

BACKGROUND： Calcium antagonists may act as neuroprotectants, diminishing the influx of calcium ions through voltage-sensitive calcium channels. When administered prophylactically, they display neuroprotective effects against hypoxic-ischemic brain damage in newborn rats. OBJECTIVE： To investigate the neuroprotective effects of flunarizine （FNZ）, lamotrigine （LTG） and the combination of both drugs, on hypoxic-ischemic brain damage in fetal rats. DESIGN AND SETTING： This randomized, complete block design was performed at the Department of Pediatrics, Shenzhen Fourth People＇s Hospital, Guangdong Medical College. MATERIALS： Forty pregnant Wistar rats, at gestational day 20, were selected for the experiment and were randomly divided into FNZ, LTG, FNZ ＋ LTG, and model groups, with 10 rats in each group. METHODS： Rats in the FNZ, LTG, and FNZ ＋ LTG groups received intragastric injections of FNZ （0.5 mg/kg/d）, LTG （10 mg/kg/d）, and FNZ （0.5 mg/kg/d） ＋ LTG （10 mg/kg/d）, respectively. Drugs were administered once a day for 3 days prior to induction of hypoxia-ischemia. Rats in the model group were not administered any drugs. Three hours after the final administration, eight pregnant rats from each group underwent model establishment hypoxia-ischemia brain damage to the fetal rats. Cesareans were performed at 6, 12, 24, and 48 hours later; and 5 fetal rats were removed from each mother and kept warm. Two fetuses without model establishment were removed by planned cesarean at the same time and served as controls. A total of 0.3 mL serum was collected from fetal rats at 6, 12, 24, and 48 hours, respectively, following birth. MAIN OUTCOME MEASURES： Serum protein concentrations of neuron-specific enolase and S-100 were measured by ELISA. Serum concentrations of brain-specific creatine kinase were measured using an electrogenerated chemiluminescence method. RESULTS： Serum concentrations of neuron-specific enolase, S-100, and brain-specific creatine kinase were significantly higher in the hypoxic-ischemic fetal rats, compared with the non-hypoxic-ischemic group. Serum concentrations of neuron-specific enolase, S-100, and brain-specific creatine kinase were significantly less in the FNZ, LTG, and FNZ ＋ LTG groups following ischemia, compared with the model group （P 〈 0.01）. However, these values were significantly greater in the FNZ and LTG groups, compared with the FNZ ＋ LTG group, following ischemia （P 〈 0.01）. CONCLUSION： Preventive antenatal use of oral FNZ and LTG has positive neuroprotective effects on intrauterine hypoxic-ischemic brain damage. The combined effect of these two drugs is superior.

Environmental enrichment promotes neural remodeling in newborn rats with hypoxic-ischemic brain damage

We evaluated the effect of hypoxic-ischemic brain damage and treatment with early environmental enrichment intervention on development of newborn rats, as evaluated by light and electron microscopy and morphometry. Early intervention with environmental enrichment intelligence training attenuated brain edema and neuronal injury, promoted neuronal repair, and increased neuronal plasticity in the frontal lobe cortex of the newborn rats with hypoxic-ischemic brain damage.

660 nm red light-enhanced bone marrow mesenchymal stem cell transplantation for hypoxic-ischemic brain damage treatment

Bone marrow mesenchymal stem cell transplantation is an effective treatment for neonatal hy- poxic-ischemic brain damage. However, the in vivo transplantation effects are poor and their survival, colonization and differentiation efficiencies are relatively low. Red or near-infrared light from 600-1,000 nm promotes cellular migration and prevents apoptosis. Thus, we hypothesized that the combination of red light with bone marrow mesenchymal stem cell transplantation would be effective for the treatment of hypoxic-ischemic brain damage. In this study, the migra- tion and colonization of cultured bone marrow mesenchymal stem cells on primary neurons after oxygen-glucose deprivation were detected using Transwell assay. The results showed that, after a 40-hour irradiation under red light-emitting diodes at 660 nm and 60 mW/cmz, an increasing number of green fluorescence-labeled bone marrow mesenchymal stem cells migrated towards hypoxic-ischemic damaged primary neurons. Meanwhile, neonatal rats with hypoxic-ischemic brain damage were given an intraperitoneal injection of 1 x 106 bone marrow mesenchymal stem cells, followed by irradiation under red light-emitting diodes at 660 nm and 60 mW/cm2 for 7 successive days. Shuttle box test results showed that, after phototherapy and bone marrow mesenchymal stem cell transplantation, the active avoidance response rate of hypoxic-ischemic brain damage rats was significantly increased, which was higher than that after bone marrow mesenchymal stem cell transplantation alone. Experimental findings indicate that 660 nm red light emitting diode irradiation promotes cells, thereby enhancing the contribution ic-ischemic brain damage. the migration of bone marrow mesenchymal stem of cell transplantation in the treatment of hypox-

TP53-induced glycolysis and apoptosis regulator alleviates hypoxia/ischemia-induced microglial pyroptosis and ischemic brain damage

Our previous studies have demonstrated that TP53-induced glycolysis and apoptosis regulator(TIGAR)can protect neurons after cerebral ischemia/reperfusion.However,the role of TIGAR in neonatal hypoxic-ischemic brain damage(HIBD)remains unknown.In the present study,7-day-old Sprague-Dawley rat models of HIBD were established by permanent occlusion of the left common carotid artery followed by 2-hour hypoxia.At 6 days before induction of HIBD,a lentiviral vector containing short hairpin RNA of either TIGAR or gasdermin D(LV-sh_TIGAR or LV-sh_GSDMD)was injected into the left lateral ventricle and striatum.Highly aggressively proliferating immortalized(HAPI)microglial cell models of in vitro HIBD were established by 2-hour oxygen/glucose deprivation followed by 24-hour reoxygenation.Three days before in vitro HIBD induction,HAPI microglial cells were transfected with LV-sh_TIGAR or LV-sh_GSDMD.Our results showed that TIGAR expression was increased in the neonatal rat cortex after HIBD and in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Lentivirusmediated TIGAR knockdown in rats markedly worsened pyroptosis and brain damage after hypoxia/ischemia in vivo and in vitro.Application of exogenous nicotinamide adenine dinucleotide phosphate(NADPH)increased the NADPH level and the glutathione/oxidized glutathione ratio and decreased reactive oxygen species levels in HAPI microglial cells after oxygen/glucose deprivation/reoxygenation.Additionally,exogenous NADPH blocked the effects of TIGAR knockdown in neonatal HIBD in vivo and in vitro.These findings show that TIGAR can inhibit microglial pyroptosis and play a protective role in neonatal HIBD.The study was approved by the Animal Ethics Committee of Soochow University of China(approval No.2017LW003)in 2017.

Neuroprotective effects of autophagy inhibition on hippocampal glutamate receptor subunits after hypoxia-ischemia-induced brain damage in newborn rats

Autophagy has been suggested to participate in the pathology of hypoxic-ischemic brain damage（HIBD）.However,its regulatory role in HIBD remains unclear and was thus examined here using a rat model.To induce HIBD,the left common carotid artery was ligated in neonatal rats,and the rats were subjected to hypoxia for 2 hours.Some of these rats were intraperitoneally pretreated with the autophagy inhibitor 3-methyladenine（10 m M in 10 μL） or the autophagy stimulator rapamycin（1 g/kg） 1 hour before artery ligation.Our findings demonstrated that hypoxia-ischemia-induced hippocampal injury in neonatal rats was accompanied by increased expression levels of the autophagy-related proteins light chain 3 and Beclin-1 as well as of the AMPA receptor subunit GluR 1,but by reduced expression of GluR 2.Pretreatment with the autophagy inhibitor 3-methyladenine blocked hypoxia-ischemia-induced hippocampal injury,whereas pretreatment with the autophagy stimulator rapamycin significantly augmented hippocampal injury.Additionally,3-methyladenine pretreatment blocked the hypoxia-ischemia-induced upregulation of Glu R1 and downregulation of GluR2 in the hippocampus.By contrast,rapamycin further elevated hippocampal Glu R1 levels and exacerbated decreased GluR2 expression levels in neonates with HIBD.Our results indicate that autophagy inhibition favors the prevention of HIBD in neonatal rats,at least in part,through normalizing Glu R1 and GluR2 expression.

Human insulin-like growth factor 1-transfected umbilical cord blood neural stem cell transplantation improves hypoxic-ischemic brain injury

Human insulin-like growth factor 1-transfected umbilical cord blood neural stem cells were transplanted into a hypoxic-ischemic neonatal rat model via the tail vein. BrdU-positive cells at day 7 post-transplantation, as well as nestin- and neuron specific enolase-positive cells at day 14 were increased compared with those of the single neural stem cell transplantation group. In addition, the proportion of neuronal differentiation was enhanced. The genetically modified cell-transplanted rats exhibited enhanced performance in correctly crossing a Y-maze and climbing an angled slope compared with those of the single neural stem cell transplantation group. These results showed that human insulin-like growth factor 1-transfected neural stem cell transplantation promotes the recovery of the leaming, memory and motor functions in hypoxic-ischemic rats.

Neuroprotective effects of ginsenoside Rg1-induced neural stem cell transplantation on hypoxic-ischemic encephalopathy

Ginsenoside Rgl is the major pharmacologically active component of ginseng, and is reported to have various therapeutic actions. To determine whether it induces the differentiation of neural stem cells, and whether neural stem cell transplantation after induction has therapeutic effects on hypoxic-ischemic encephalopathy, we cultured neural stem cells in 10-80 ~tM ginsenoside Rgl. Immunohistochemistry revealed that of the concentrations tested, 20 mM ginsenoside Rgl had the greatest differentiation-inducing effect and was the concentration used for subsequent exper- iments. Whole-cell patch clamp showed that neural stem cells induced by 20 jaM ginsenoside Rgl were more mature than non-induced cells. We then established neonatal rat models of hypox- ic-ischemic encephalopathy using the suture method, and ginsenoside Rgl-induced neural stem cells were transplanted via intracerebroventricular injection. These tests confirmed that neural stem cells induced by ginsenoside had fewer pathological lesions and had a significantly better behavioral capacity than model rats that received saline. Transplanted neural stem cells expressed neuron-specific enolase, and were mainly distributed in the hippocampus and cerebral cortex. The present data suggest that ginsenoside Rgl-induced neural stem cells can promote the partial recovery of complicated brain functions in models of hypoxic-ischemic encephalopathy.

Dedifferentiated human umbilical cord mesenchymal stem cell reprogramming of endogenous hSDF-1a expression participates in neural restoration in hypoxic-ischemic brain damagerats

The transplantation of human umbilical cord mesenchymal stem cells(hUC-MSCs)can promote hypoxic-ischemic brain damage(HIBD)nerve repair,but finding suitable seed cells to optimize transplantation and improve treatment efficiency is an urgent problem to be solved.In this study,we induced hUC-MSCs into dedifferentiated hUC-MSCs(De-hUC-MSCs),and the morphology,stem cell surface markers,proliferation and tri-directional differentiation ability of the De-hUC-MSCs and hUC-MSCs were detected.A whole-gene chip was utilized for genome cluster,gene ontology and KEGG pathway analyses of differentially expressed genes.De-hUC-MSCs were transplanted into HIBD rats,and behavioral experiments and immunofluorescence assays were used to assess the therapeutic effect.A lentivirus vector for human stromal cell-derived factor-1(hSDF-1a)was constructed,and the role of hSDF-1a in the neuroprotective effect and mechanism of De-hUC-MSCs was verified.De-hUC-MSCs displayed similar cell morphology,stem cell surface marker expression,cell proliferation and even three-dimensional differentiation ability as hUC-MSCs but exhibited greater treatment potential in vivo.The reprogramming mechanism of hSDF-1a participated in the dedifferentiation process.By successfully constructing a stable hSDF-1a cell line,we found that De-hUC-MSCs might participate in nerve repair through the hSDF-1a/CXCR4/PI3K/Akt pathway.De-hUC-MSCs reprogramming of endogenous hSDF-1a expression may mediate the hSDF-1a/CXCR4/PI3K/Akt pathway involved in nerve repair in HIBD rats.

茶黄素通过抑制细胞过度自噬减轻新生大鼠缺氧缺血性脑损伤

目的基于沉默信息调节因子2相关酶1(SIRT1)/叉头盒蛋白O1(FoxO1)信号通路探讨茶黄素(Theaflavins,TFs)在新生大鼠缺氧缺血性脑损伤(HIBD)中的作用及机制。方法将7日龄Sprague-Dawley(SD)大鼠随机分为假手术组(sham组)、模型组(HIBD组)、茶黄素组(TFs+HIBD组)、SIRT1抑制剂组(TFs+HIBD+Ex-527组),每组40只。假手术组仅游离右侧颈总动脉,不进行缺血缺氧处理;模型组采用改良Rice-Vannucci法,游离并结扎右侧颈总动脉后缺氧制成HIBD模型;茶黄素组和SIRT1抑制剂组在建立HIBD模型前,给予茶黄素灌胃,SIRT1抑制剂组给予Ex-527侧脑室注射。各组于术后6,12,24,48,72 h对新生大鼠进行Longa评分、一般状态、行为学检测及脑组织称重;苏木素-伊红染色(HE)染色观察脑组织病理学改变;蛋白质印迹法(Western blotting)检测SIRT1、FoxO1、Ac-FoxO1、Beclin1、LC3-Ⅱ/Ⅰ在蛋白质水平的表达。结果与sham组比较,HIBD组新生大鼠精神不振,神经功能缺损评分显著升高(P<0.05),体质量增长迟缓(P<0.01),翻正反射时间明显延长(P<0.05),右侧脑组织质量增大(P<0.05),HE染色可见大脑皮层区神经元数目减少,SIRT1、FoxO1蛋白表达明显降低(P<0.01),Ac-FoxO1及自噬相关蛋白Beclin1、LC3Ⅱ/Ⅰ的表达量升高(P<0.01)。与HIBD组比较,TFs+HIBD组新生大鼠精神状态好转,神经功能缺损评分下降(P<0.05),体质量增长较快(P<0.01),翻正反射时间缩短(P<0.05),右侧脑组织质量减轻(P<0.05),HE染色可见脑组织神经元数目增多,SIRT1、FoxO1蛋白表达升高(P<0.01),Ac-FoxO1及自噬相关蛋白的表达量降低(P<0.01)。与TFs+HIBD组比较,TFs+HIBD+Ex-527组新生大鼠神经功能缺损评分升高(P<0.05),体质量增长迟缓(P<0.01),翻正反射时间延长(P<0.05),右侧脑组织质量增大(P<0.05),HE染色可见脑组织神经元细胞减少,SIRT1、FoxO1蛋白表达降低(P<0.01),Ac-FoxO1及自噬相关蛋白的表达量升高(P<0.01)。结论TFs可通过激活SIRT1/FoxO1信号转导通路抑制HIBD引起的过度细胞自噬,从而减轻神经元细胞的损伤。

天麻素对缺血缺氧诱导的小胶质细胞中TLR4表达的影响

目的:探究天麻素(GAS)对缺血缺氧性损伤(HIBD)后小胶质细胞toll样受体4(TLR4)表达的影响。方法:体内创建新生大鼠HIBD模型,将30只3 d龄SD大鼠随机组成3组:假手术组(sham)、HIBD模型组、HIBD模型+GAS干预组(HIBD+G);体外创建BV2细胞氧糖剥夺(OGD)模型,实验随机设置对照组(control)、OGD组、OGD+GAS干预组(OGD+G)。Western Blot和免疫荧光双标染色技术均检测体外各组细胞及体内大鼠模型左侧大脑胼胝体区TLR4的表达。结果:OGD诱导的小胶质细胞中TLR4表达显著增加;GAS干预后TLR4表达显著减少(P<0.05)。结论:GAS激活的小胶质细胞TLR4的表达具有抑制效应,从而对HIBD发挥神经保护作用。

EP对HIBD新生大鼠脑组织BCL-2及BAX表达的影响

目的:观察丙酮酸乙酯(EP)对缺血缺氧性脑损伤新生大鼠脑组织Bcl-2及Bax蛋白表达的影响,探讨EP在新生大鼠缺血缺氧性脑损伤脑组织中保护作用的可能机制。方法:90只Wistar新生大鼠,随机分为3组:A组为对照组,B组为模型组,C组为干预组。给动物吸入含有92%氮气和8%氧气混合气体建立新生大鼠缺氧缺血性脑损伤(HIBD)动物模型,免疫组化法观察大鼠海马区Bax、Bcl-2表达变化。结果:A组Bax、Bcl-2表达变化不明显;B组Bcl-2表达明显减少,与A组、C组比较差异有统计学意义(P<0.05);C组Bcl-2表达较B组明显增多(P<0.05)。B组Bax表达明显增多,与A组、C组比较差异有统计学意义(P<0.05),C组Bax表达较B组明显减少(P<0.05)。结论:丙酮酸乙酯对新生大鼠缺血缺氧性脑损伤脑组织有保护性作用,此作用可能与其调节Bcl-2和Bax表达水平有关。

白藜芦醇甙对HIBD新生大鼠海马c-Jun表达的影响

目的 探讨白藜芦醇甙对缺氧缺血性脑损伤（HIBD）新生大鼠大脑海马c Jun表达的影响.方法 选择新生7日龄SD大鼠52只,随机分为假手术对照组（NS组）、阴性对照组（NG组）、缺氧缺血组（HI组）、白藜芦醇甙干预组（PD组）.通过结扎左颈总动脉及通入8%的氧气2小时制备新生大鼠缺氧缺血性脑损伤模型,应用免疫组织化学及蛋白质免疫印迹法测定缺氧缺血后24小时大鼠海马c Jun表达.结果 免疫组织化学结果 显示,HI组海马CA1、CA3区c Jun表达明显高于NS组和NG组（CA1区NS组t=15.39,NG组t=14.88;CA3区NS组t=11.16,NG组t=11.88,均P〈0.01）,PD组海马CA1、CA3区c Jun表达明显低于HI组（CA1区t=12.61,CA3区t=10.22,均P〈0.01）.蛋白质免疫印迹法结果 显示,HI组c Jun表达明显高于NS组和NG组（NS组t=33.67,NG组t=32.97,均P〈0.01）,PD组c Jun表达明显低于HI组（t=29.78,P〈0.01）.结论 白藜芦醇甙可能降低缺氧缺血性脑损伤新生大鼠大脑海马c Jun的表达,对于缺氧缺血后的神经元可能具有早期保护作用.

青蒿琥酯通过抑制NLRP3炎性体激活和炎性细胞因子分泌减轻新生大鼠缺氧缺血性脑损伤

目的研究青蒿琥酯对新生大鼠缺血缺氧性脑损伤(HIBD)的保护作用及其作用机制。方法7日龄新生SD大鼠随机分为假手术组、模型组、5 mg/kg青蒿琥酯组、10 mg/kg青蒿琥酯组、20 mg/kg青蒿琥酯组、6 mg/kg地塞米松组,每组18只。除假手术组外,其余各组建立HIBD模型,假手术组只需分离左颈侧总动脉,不行结扎和氮氧混合气体通气处理。在手术后,各组立刻腹腔注射对应药物,假手术组和模型组大鼠注射等体积的生理盐水,之后每日一次,共给药5次。末次给药1 h后,对各组大鼠进行神经功能缺损评分,大鼠处死后检测脑含水量,观察大鼠海马CA1区脑组织病理学改变,原位末端转移酶标记技术(TUNEL)检测神经细胞凋亡情况,ELISA分别检测各组大鼠脑组织和外周血中白细胞介素1β(IL⁃1β)、IL⁃6、肿瘤坏死因子α(TNF⁃α)的水平,Western blot法检测各组大鼠海马CA1区脑组织含pyrin结构域核苷酸结合寡聚结构域样受体家族蛋白3(NLRP3)、含胱天蛋白酶募集结构域凋亡相关斑点样蛋白(ASC)、胱天蛋白酶1(caspase⁃1)蛋白表达。结果与模型组比较,(10、20)mg/kg青蒿琥酯组和地塞米松组大鼠神经功能缺损评分下降,脑组织病理损伤减轻,脑含水量明显减少,海马神经元细胞凋亡数明显减少,脑组织和外周血中IL⁃1β、IL⁃6、TNF⁃α水平明显降低,NLRP3、ASC、caspase⁃1水平明显降低。结论青蒿琥酯能够改善HIBD新生大鼠的神经功能、缓解脑部损伤、减轻脑水肿,对HIBD起保护作用,这可能与抑制NLRP3炎性体激活,减少炎性细胞因子的分泌有关。

天麻素对激活小胶质细胞miR-124和miR-155表达的影响

目的:研究天麻素对激活的小胶质细胞miR-124和miR-155表达含量的影响。方法:分为体内实验和体外实验,体内实验:将新生3 d的SD大鼠随机分为假手术组(sham)、缺血缺氧模型组(HIBD)、缺血缺氧+天麻素干预组(G+HIBD),体外实验:将BV2细胞随机分为对照组(control)、氧糖剥夺组(OGD)、天麻素+氧糖剥夺组(G+OGD),real time RT-PCR检测大鼠胼胝体及BV2细胞miR-124和miR-155的表达变化。结果:体内、体外real time RT-PCR结果显示:与sham、control组相比,HIBD组大鼠胼胝体及OGD处理的BV2细胞、OGD组的miR-155表达水平升高,miR-124表达水平降低(P<0.05);使用天麻素干预后,miR-155表达水平降低,miR-124表达水平升高(P<0.05)。结论:天麻素能促进激活的小胶质细胞miR-124的表达,抑制miR-155表达,从而发挥其神经保护作用。