Do pyroptosis, apoptosis, and necroptosis (PANoptosis) exist in cerebral ischemia? Evidence from cell and rodent studies

Some scholars have recently developed the concept of PANoptosis in the study of infectious diseases where pyroptosis,apoptosis and necroptosis act in consort in a multimeric protein complex,PANoptosome.This allows all the components of PANoptosis to be regulated simultaneously.PANoptosis provides a new way to study the regulation of cell death,in that different types of cell death may be regulated at the same time.To test whether PANoptosis exists in diseases other than infectious diseases,we chose cerebral ischemia/reperfusion injury as the research model,collected articles researching cerebral ischemia/reperfusion from three major databases,obtained the original research data from these articles by bibliometrics,data mining and other methods,then integrated and analyzed these data.We selected papers that investigated at least two of the components of PANoptosis to check its occurrence in ischemia/reperfusion.In the cell model simulating ischemic brain injury,pyroptosis,apoptosis and necroptosis occur together and this phenomenon exists widely in different passage cell lines or primary neurons.Pyroptosis,apoptosis and necroptosis also occurred in rat and mouse models of ischemia/reperfusion injury.This confirms that PANoptosis is observed in ischemic brain injury and indicates that PANoptosis can be a target in the regulation of various central nervous system diseases.

Involvement of the Wnt signaling pathway and cell apoptosis in the rat hippocampus following cerebral ischemia/reperfusion injury

We investigated the role of the Wnt signaling pathway in cerebral ischemia/reperfusion injury by examining β-catenin and glycogen synthase kinase-3β protein expression in the rat hippocampal CA1 region following acute cerebral ischemia/reperfusion. Our results demonstrate that cell apoptosis increases in the CA1 region following ischemia/reperfusion. In addition, β-catenin and glycogen synthase kinase-3β protein expression gradually increases, peaking at 48 hours following reperfusion. Dickkopf-1 administration, after cerebral ischemia/reperfusion injury, results in decreased cell apoptosis, and β-catenin and glycogen synthase kinase-3β expression, in the CA1 region. This suggests that β-catenin and glycogen synthase kinase-3β, both components of the Wnt signaling pathway, participate in cell apoptosis following cerebral ischemia/reperfusion injury.

Effects of L-Tetrahydropalmatine on Neuron Apoptosis during Acute Cerebral Ischemia-Reperfusion of Rats

To investigate the effects of L-Tetrahydropalmatine (L-THP ) on neuron apoptosis during acute cerebral ischemia-reperfusion of rats and explore the effects of heat shock protein (HSP) on neuron apoptosis, Wistar rats were randomly divided into 3 groups: normal group, ischemia- reperfusion group and treatment group. The condition of neuron apoptosis, the survival state of neuron, pathological changes under an electron microscope and the number of HSP70 positive cells were measured in all groups. Results showed that the apoptosis neuron number was increased obviously at the 24th h during reperfusion and was further increased at the 48th h, the 72th h. While the number of survival neurons was decreased gradually with the prolongation of reperfusion time. Treatment with L-THP could decrease the apoptosis neuron number but increase the survival neuron number and the HSP70 positive cell number. Our study suggested that L-THP could decrease apoptosis and necrosis of neuron, up-regulate the expression of HSP70 and protect the cerebral ischemic injury.

Inhibition of cerebral ischemia/reperfusion injuryinduced apoptosis:nicotiflorin and JAK2/STAT3 pathway

Nicotiflorin is a flavonoid extracted from Carthamus tinctorius.Previous studies have shown its cerebral protective effect,but the mechanism is undefined.In this study,we aimed to determine whether nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis through the JAK2/STAT3 pathway.The cerebral ischemia/reperfusion injury model was established by middle cerebral artery occlusion/reperfusion.Nicotiflorin（10 mg/kg） was administered by tail vein injection.Cell apoptosis in the ischemic cerebral cortex was examined by hematoxylin-eosin staining and terminal deoxynucleotidyl transferase d UTP nick end labeling assay.Bcl-2 and Bax expression levels in ischemic cerebral cortex were examined by immunohistochemial staining.Additionally,p-JAK2,p-STAT3,Bcl-2,Bax,and caspase-3 levels in ischemic cerebral cortex were examined by western blot assay.Nicotiflorin altered the shape and structure of injured neurons,decreased the number of apoptotic cells,down-regulates expression of p-JAK2,p-STAT3,caspase-3,and Bax,decreased Bax immunoredactivity,and increased Bcl-2 protein expression and immunoreactivity.These results suggest that nicotiflorin protects against cerebral ischemia/reperfusion injury-induced apoptosis via the JAK2/STAT3 pathway.

Optimal concentration and time window for proliferation and differentiation of neural stem cells from embryonic cerebral cortex: 5% oxygen preconditioning for 72 hours

Hypoxia promotes proliferation and differentiation of neural stem cells from embryonic day 12 rat brain tissue, but the concentration and time of hypoxic preconditioning are controversial. To address this, we cultured neural stem cells isolated from embryonic day 14 rat cerebral cortex in 5% and 10% oxygen in vitro. MTT assay, neurosphere number, and immunofluorescent staining found that 5% or 10% oxygen preconditioning for 72 hours improved neural stem cell viability and proliferation. With prolonged hypoxic duration （120 hours）, the proportion of apoptotic cells increased. Thus, 5% oxygen preconditioning for 72 hours promotes neural stem cell prolif- eration and neuronal differentiation. Our findings indicate that the optimal concentration and duration of hypoxic preconditioning for promoting proliferation and differentiation of neural stem cells from the cerebral cortex are 5% oxygen for 72 hours.

Ultra-early treatment of bone marrow-derived mesenchymal stem cells for focal cerebral ischemia/ reperfusion injury

The time point at which bone marrow-derived mesenchymal stem cells（BMSCs）can be used in transplantation for the treatment of ischemic brain injury remains unclear.In the present study,BMSCs were transplanted to the ischemic site 90 minutes post-ischemia.The results demonstrated that the transplanted BMSCs improved neurological function,reduced infarct volume,increased survivin expression,decreased caspase-3 expression and reduced apoptosis.This suggests that BMSCs transplanted at an ultra-early stage ameliorated brain ischemia by increasing survivin expression,decreasing caspase-3 expression and reducing apoptosis at the ischemia/reperfusion injury site.

Cerebral dopamine neurotrophic factor promotes the proliferation and differentiation of neural stem cells in hypoxic environments

Previous research found that cerebral dopamine neurotrophic factor(CDNF)has a protective effect on brain dopaminergic neurons,and CDNF is regarded as a promising therapeutic agent for neurodegenerative diseases.However,the effects of CDNF on the proliferation,differentiation,and apoptosis of neural stem cells(NSCs),which are very sensitive to hypoxic environments,remain unknown.In this study,NSCs were extracted from the hippocampi of fetal rats and cultured with different concentrations of CDNF.The results showed that 200 nM CDNF was the optimal concentration for significantly increasing the viability of NSCs under non-hypoxic environmental conditions.Then,the cells were cultured with 200 nM CDNF under the hypoxic conditions of 90%N_2,5%CO_2,and 5%air for 6 hours.The results showed that CDNF significantly improved the viability of hypoxic NSCs and reduced apoptosis among hypoxic NSCs.The detection of markers showed that CDNF increased the differentiation of hypoxic NSCs into neurons and astrocytes.CDNF also reduced the expression level of Lin28 protein and increased the expression of Let-7 mRNA in NSCs,under hypoxic conditions.In conclusion,we determined that CDNF was able to reverse the adverse proliferation,differentiation,and apoptosis effects that normally affect NSCs in a hypoxic environment.Furthermore,the Lin28/Let-7 pathway may be involved in this regulated function of CDNF.The present study was approved by the Laboratory Animal Centre of Southeast University,China(approval No.20180924006)on September 24,2018.

Electroacupuncture reduces apoptotic index and inhibits p38 mitogen-activated protein kinase signaling pathway in the hippocampus of rats with cerebral ischemia/reperfusion injury

Electroacupuncture attenuates cerebral hypoxia and neuronal apoptosis induced by cerebral ischemia/reperfusion injury.To further identify the involved mechanisms,we assumed that electroacupuncture used to treat cerebral ischemia/reperfusion injury was associated with the p38 mitogen-activated protein kinase（MAPK） signaling pathway.We established rat models of cerebral ischemia/reperfusion injury using the modified Zea-Longa＇s method.At 30 minutes before model establishment,p38 MAPK blocker SB20358 was injected into the left lateral ventricles.At 1.5 hours after model establishment,electroacupuncture was administered at acupoints of Chize（LU5）,Hegu（LI4）,Zusanli（ST36）,and Sanyinjiao（SP6） for 20 minutes in the affected side.Results showed that the combination of EA and SB20358 injection significantly decreased neurologic impairment scores,but no significant differences were determined among different interventional groups.Hematoxylin-eosin staining also showed reduced brain tissue injuries.Compared with the SB20358 group,the cells were regularly arranged,the structures were complete,and the number of viable neurons was higher in the SB20358 ＋ electroacupuncture group.Terminal deoxynucleotidyl transferase（Td T）-mediated d UTP nick-end labeling assay showed a decreased apoptotic index in each group,with a significant decrease in the SB20358 ＋ electroacupuncture group.Immunohistochemistry revealed reduced phosphorylated p38 expression at 3 days in the electroacupuncture group and SB20358 ＋ electroacupuncture group compared with the ischemia/reperfusion group.There was no significant difference in phosphorylated p38 expression between the ischemia/reperfusion group and SB20358 group.These findings confirmed that the electroacupuncture effects on mitigating cerebral ischemia/reperfusion injury are possibly associated with the p38 MAPK signaling pathway.A time period of 3 days could promote the repair of ischemic cerebral nerves.

Effects of Salvia miltiorrhiza Bge.f.alba on neuronal regeneration following cerebral ischemia/reperfusion

BACKGROUND： Subsequent to cerebral ischemic injury, endogenous neural stem cells are activated, but ischemia-induced neuronal loss is not compensated by ischemic injury-induced neural regeneration. Salvia （S.） miltiorrhiza Bge.f.alba （Baihua Danshen, a Chinese herbal medicine） could enhance learning and memory functions, as well as promote neural regeneration. OBJECTIVE： To observe the effects of S. miltiorrhiza Bge.f.alba on recovery from cerebral ischemia-reperfusion injury, and the influence on neuronal regeneration and differentiation. DESIGN, TIME AND SETTING： Randomized, controlled, animal experiments were performed at the Experimental Animal Center and Neurobiology Laboratory of Taishan Medical College in September of 2006. MATERIALS： S. miltiorrhiza Bge.f.alba was provided by Taishan Medical College Botanic Garden, Taian, China; dl-3n-butylphthalide （NBP） soft capsule was purchased from NBP Pharmaceutical, Shijiazhuang, China; mouse anti-bromodeoxyuridine antibody, rabbit anti-NF200 antibody, and bromodeoxyuridine were purchased from Sigma, Louis, MO, USA; Annexin V-fluorescein isothiocyanate/PI apoptosis kit was purchased from Nanjing Comissariado Biological Technology Development, Nanjing, China. METHODS： Adult Sprague Dawley rats were randomly assigned to sham surgery, model （cerebral ischemia and reperfusion, without administration）, S. miltiorrhiza Bge.f.alba, and NBP groups. Following establishment of the cerebral ischemia/reperfusion model, S. miltiorrhiza Bge.f.alba or NBP （1 mL/100 g） was respectively perfused at 30 minutes following cerebral ischemia/reperfusion. MAIN OUTCOME MEASURES： Alterations in cerebral blood flow before and after ischemia/reperfusion, NF200- and bromodeoxyuridine-double positive cells in striatum of affected tissues, as well as neuronal apoptosis rate at days 5 and 7 following cerebral ischemia/reperfusion. RESULTS： Subsequent to cerebral ischemia reperfusion, cerebral blood flow was reduced. Following treatment with S. miltiorrhiza Bge.f.alba, cerebral blood flow significantly increased （P 〈 0.05）. NBP treatment was inferior to S. miltiorrhiza Bge.f.alba with regard to stabilization of cerebral blood flow （P 〈 0.05）. S. miltiorrhiza Bge.f.alba significantly increased the number of newly formed neurons in rats following cerebral ischemia （P 〈 0.05） and significantly reduced neuronal apoptosis （P 〈 0.05）, with no significant difference compared with NBP treatment （P 〉 0.05）. CONCLUSION： S. miltiorrhiza Bge.f.alba significantly increased cerebral blood flow, reduced neuronal apoptosis, and promoted neuronal regeneration in rats with cerebral ischemia/reperfusion impairment.

Cerebroprotection with recombinant neuroglobin plasmid in a rat model of focal cerebral ischemia

BACKGROUND： Adenovirus has been used to develop neuroglobin （Ngb） vectors. Although transfection efficiency is high, induced gene mutation, cytotoxicity, inflammation, and low exogenous gene content have limited its application. OBJECTIVE： To observe the effects of recombinant Ngb plasmid in a rat model of focal cerebral ischemia. DESIGN, TIME AND SETTING： Genetically engineered, randomized, controlled, animal experiment was performed at the Laboratory of Chongqing Medical University from May 2006 and January 2007. MATERIALS： 2, 3, 5-triphenyltetrazolium chloride was purchased from Shanghai Sangon Biological Engineering Technology and Services. Rabbit anti-rat Bcl-2 polyclonal antibody, rabbit anti-rat β-actin monoclonal antibody, and FITC-labeled goat anti-rabbit IgG were purchased from Sigma, USA. TUNEL apoptosis kit was purchased from Roche, Germany. METHODS： A total of 54 male, adult, Wistar rats were randomly assigned to 3 groups （n=18）： normal saline, plasmid control, and recombinant Ngb （pCDNA3.1 （＋）/Ngb）. Normal saline, plasmid pCDNA3.1 （＋）, and recombinant plasmid pCDNA3.1 （＋）/Ngb were separately injected into two sites in the rat cerebral cortex, and models of focal ischemia were established by occlusion of the right middle cerebral artery after 24 hours. MAIN OUTCOME MEASURES： Local ischemic damage was detected by 2, 3, 5- triphenyltetrazolium chloride staining, apoptosis in the penumbra was confirmed using the TUNEL method, and Bcl-2 protein expression in the penumbra was determined by indirect immunofluorescent staining and Western blot analysis. RESULTS： Compared with the normal saline and plasmid control groups, cerebral infarction size and the number of apoptotic cells in the pCDNA3.1 （＋）/Ngb group were significantly reduced （P 〈 0.01）. The percentage of Bcl-2-positive cells in the penumbra of the pCDNA3.1 （＋）/Ngb group was significantly increased （P 〈 0.01）. The relative expression level of Bcl-2 protein was increased by 40%-50%. CONCLUSION： Recombinant plasmid pCDNA3.1/Ngb provides neuroprotection by upregulating Bcl-2 expression and inhibiting cell apoptosis in the penumbra.

Hypoxic preconditioning reduces NLRP3 inflammasome expression and protects against cerebral ischemia/reperfusion injury

Hypoxic preconditioning can protect against cerebral ischemia/reperfusion injury. However, the underlying mechanisms that mediate this effect are not completely clear. In this study, mice were pretreated with continuous, intermittent hypoxic preconditioning;1 hour later, cerebral ischemia/reperfusion models were generated by middle cerebral artery occlusion and reperfusion. Compared with control mice, mice with cerebral ischemia/reperfusion injury showed increased Bederson neurological function scores, significantly increased cerebral infarction volume, obvious pathological damage to the hippocampus, significantly increased apoptosis;upregulated interleukin-1β, interleukin-6, and interleukin-8 levels in brain tissue;and increased expression levels of NOD-like receptor family pyrin domain containing 3(NLRP3), NLRP inflammasome-related protein caspase-1, and gasdermin D. However, hypoxic preconditioning significantly inhibited the above phenomena. Taken together, these data suggest that hypoxic preconditioning mitigates cerebral ischemia/reperfusion injury in mice by reducing NLRP3 inflammasome expression. This study was approved by the Medical Ethics Committee of the Fourth Hospital of Baotou, China(approval No. DWLL2019001) in November 2019.

Anti-apoptotic effects of aspirin following cerebral ischemia-reperfusion injury in rats

BACKGROUND： The pharmacological effects of aspirin on apoptosis are complex. The underlying mechanisms have not been properly defined. OBJECTIVE： To observe the effect of different doses of aspirin on brain cell apoptosis following focal cerebral iscbemia-reperfusion injury （CIRI） in rats. DESING, TIME AND SETTING： A randomized, controlled, animal experiment, performed at the School of Medicine and Pharmaceutics, Jiangnan University between June and October 2006. MATERIALS： Twenty-six male, adult, Sprague Dawley rats （grade Ⅱ）, weighing 240-290 g, were obtained from Shanghai Experimental Animal Center, Chinese Academy of Sciences. Aspirin was provided by Sigma （USA）. METHODS： The rats were randomly divided into four groups： sham-operation （SO）, CIRI ＋ vehicle, CIRI ＋ aspirin （6 mg/kg）, and CIRI ＋ aspirin （60 mg/kg）. Rats in the lesion groups were intragastrically administrated saline, aspirin （6 mg/kg）, or aspirin （60 mg/kg）, respectively. MAIN OUTCOME MEASURES： The number of pyramidal neurons with normal appearance in the cerebral cortex at 24 mm from the midline; apoptotic cell death as measured by TUNEL; Bcl-2 and Bax protein localization was determined by immunohistochemistry; malondialdehyde （MDA） and super oxidation （SOD） content were determined by biochemistry method; adenosine triphosphate （ATP） content measured by capillary electrophoresis. RESULTS： Following CIRI, the following parameters were altered compared with sham-operated animals： the number of neurons with normal appearance was significantly reduced in the cerebral cortex; the number of apoptotic cells increased; Bax protein expression was enhanced; and the ratio between Bcl-2 and Bax decreased. In addition, MDA content increased significantly, whereas ATP content decreased （P 〈 0.01）. Aspirin ameliorated the loss of healthy pyramidal neurons. Both 6 and 60 mg/kg aspirin increased the ratio between Bcl-2 and Bax, with no significant difference between the treatment groups. In addition, 60 mg/kg aspirin decreased MDA content and increased ATP levels. However, 6 mg/kg aspirin did not have the same effect. CONCLUSION： Aspirin reduced the number of apoptotic cells following CIRI. These results suggest that the neuroprotective mechanism of aspirin could be related to elevated Bcl-2 protein levels or decreased Bax protein expression. The increase in the ratio of Bcl-2 to Bax appears to be a common anti-apoptotic mechanism of aspirin.

Expression of nerve growth factor precursor, mature nerve growth factor and their receptors during cerebral ischemia-reperfusion injury

We investigated nerve growth factor precursor （proNGF） and mature NGF expression in ischemic and non-ischemic cortices after cerebral ischemia-reperfusion injury. In both ischemic and non-ischemic cortices, proNGF was found to be present in the extracellular space and cytoplasm. In addition, mature NGF was expressed in extracellular space, but with a very low signal. In ischemic cortex only, proNGF was significantly decreased, reaching a minimal level at 1 day. Mature NGF was increased at 4 hours, then reached a minimal level at 3 days. The p75 neurotrophin receptor （p75NTR） was significantly decreased after ischemia, and increased at 3 days after ischemia. These results confirmed that proNGF was the predominant form of NGF during the pathological process of cerebral ischemia-repeffusion injury. In addition, our findings suggest that ischemic injury may influence the conversion of proNGF to mature NGF, and that proNGF/p75NTR may be involved in reperfusion injury.

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.

基于miR-153/TREM1探讨健神利水方对脑出血大鼠神经细胞凋亡的作用机制

目的探究健神利水方对脑出血大鼠神经细胞凋亡的作用机制。方法通过miRNA微阵列芯片和RT-PCR分析出脑出血中miR-153的表达,观察并分析miR-153与脑出血神经细胞凋亡关系;预测miR-153的靶基因,采用双荧光素酶报告基因实验观察其与靶基因的结合情况,观察过表达和抑制miR-153对靶基因的影响,随后,明确靶基因与脑出血神经细胞凋亡关系,最后观察健神利水方对miR-153、靶基因的影响,最终探究健神利水方对脑出血大鼠神经细胞凋亡的相关机制。结果微阵列芯片和RT-PCR检测表明miR-153在脑出血中是低表达的(P<0.05),miR-153与神经细胞凋亡呈负相关(R:-0.875,P=0.0002)。在线数据库TargetScan和miRDB显示miR-153与TREM1具有结合区域,双荧光素酶报告基因实验证明两者具有结合关系,当miR-153过表达时,TREM1表达量会下调,相反,当miR-153抑制时,TREM1表达量会上调,TREM1与神经细胞凋亡呈正相关(R:0.857,P<0.001)。健神利水方组的TREM1表达量、神经细胞凋亡数量、神经功能缺损评分均低于模型组(P<0.05),miR-153表达量高于模型组(P<0.05)。健神利水方+miR-153抑制组的TREM1表达量、神经细胞凋亡数量、神经功能缺损评分均高于健神利水方组(P<0.05)。结论健神利水方通过促进miR-153表达,抑制TREM1表达来达到抑制脑出血大鼠神经细胞凋亡,保护神经功能。

过表达BIRC5基因对氧糖剥夺/复氧诱导的脑微血管内皮细胞活性及VEGF表达的影响

目的探讨过表达BIRC5基因对氧糖剥夺/复氧(OGD/R)诱导的小鼠脑微血管内皮细胞损伤的保护作用,并分析其可能的机制。方法将小鼠源性脑微血管内皮细胞,根据不同干预方式分为正常对照组(细胞正常培养)、细胞损伤组(细胞正常培养24 h,随后OGD3h/R3h损伤细胞)、BIRC5干预组(细胞预先转染腺病毒-BIRC5质粒并培养24 h,随后OGD3h/R3h处理)和阴性对照组(细胞预先转染腺病毒空质粒并培养24 h,随后OGD3h/R3h处理)。采用激光共聚焦显微镜观察各组细胞形态学变化;用MTT法和流式细胞仪分别检测各组细胞存活率和凋亡率;用RT-PCR和免疫印迹法分别检测各组细胞BIRC5和VEGF mRNA及蛋白表达。结果正常对照组的细胞骨架微丝彼此连接,分布规则,丝网状有序排列;细胞损伤组和阴性对照组的细胞微丝断裂,收缩变短或移向周边,微丝网状排列紊乱,可见细胞外形皱缩,间隙加大,少部分微丝缺失出现空隙;BIRC5干预组的细胞微丝连接,形态成长梭形,排列较规则,可见细胞间隙缩小,显示过表达BIRC5基因能够减轻损伤细胞的骨架微丝紊乱。与正常对照组相比,细胞损伤组、BIRC5干预组及阴性对照组细胞存活率降低,而细胞凋亡率增高,差异均有统计学意义(P<0.05);与细胞损伤组相比,BIRC5干预组的细胞存活率增高,而细胞凋亡率降低,差异有统计学意义(P<0.05)。与正常对照组相比,细胞损伤组、BIRC5干预组和阴性对照组的BIRC5和VEGF的mRNA及蛋白表达降低,差异有统计学意义(P<0.05);与细胞损伤组相比,BIRC5干预组细胞BIRC5和VEGF的mRNA及蛋白表达增高,差异有统计学意义(P<0.05)。结论过表达BIRC5基因对OGD/R诱导的脑微血管内皮细胞损伤具有保护作用,机制可能与上调VEGF表达有关,提示BIRC5调控VEGF表达促进血管新生可能是脑侧支循环建立和形成的重要机制之一。

香叶醇通过调控Nrf2/HO-1途径调节氧化应激减轻大鼠脑缺血/再灌注损伤

目的研究香叶醇对脑缺血/再灌注(cerebral ischemia reperfusion injury,CIRI)后Nrf2/HO-1信号通路的调控作用。方法随机将雄性SD大鼠分成假手术组(sham)、假手术+200 mg·kg^(-1)香叶醇组、缺血/再灌注(I/R)组、I/R+50 mg·kg^(-1)香叶醇组、I/R+100 mg·kg^(-1)香叶醇组、I/R+200 mg·kg^(-1)香叶醇组、依达拉奉组,I/R+brusatol(Nrf2抑制剂)组、I/R+200 mg·kg^(-1)香叶醇+brusatol组。大鼠在MCAO术前5 d连续腹腔注射香叶醇,术后再次腹腔注射香叶醇。假手术组和假手术+200 mg·kg^(-1)香叶醇组只分离血管不插栓线,其余组别使用线栓法建立大鼠CIRI损伤模型。通过改良神经功能评分表评定大鼠神经功能受损情况;TTC脑片染色测定大鼠脑梗死体积;HE染色观察大鼠缺血侧皮层受损情况;TUNEL凋亡染色测定大鼠皮层细胞凋亡情况;测定氧化应激相关参数;免疫组织化学染色法检测Nrf2和HO-1蛋白的表达;Western blot检测受损侧皮层组织中目的蛋白表达水平。结果与模型组相比,香叶醇给药组能明显改善大鼠神经损伤症状、减少脑梗死体积和改善大鼠脑受损皮层的损伤情况;同时减少细胞凋亡的发生;并且香叶醇干预组能明显增加大鼠右侧皮质Nrf2/HO-1蛋白的表达,降低氧化应激水平。结论香叶醇通过激活Nrf2/HO-1信号途径,改善缺血/再灌注所致的大鼠缺血性脑损伤。

ST2825通过调节小胶质细胞极化减轻脑缺血-再灌注损伤的研究

目的研究ST2825对脑缺血-再灌注损伤小胶质细胞的作用。方法处于对数生长期小鼠小胶质细胞BV2随机分为对照组(Con)、模型组(Mod)和ST2825低剂量处理组(ST2825L)、ST2825高剂量处理组(ST2825H),采用氧糖剥夺/再复氧(OGD/R)诱导缺血-再灌注模型,对细胞进行ST2825低剂量(5μmol/L)、高剂量(10μmol/L)处理。采用cell counting kit-8(CCK-8)方法检测活细胞数量,采用流式细胞术检测细胞活性氧(ROS)水平、凋亡及细胞极化状态,采用qPCR检测TNF-α、IL-10基因表达水平,采用免疫印迹(Western blotting)方法检测Caspase-1、cleaced Caspase-1、NLRP3、iNOS、IL-1及IL-18蛋白表达水平。结果CCK-8显示,与Con组相比,OGD/R后Mod组细胞活力极显著降低(P<0.01);与Mod组相比,ST2825L组、ST2825H组细胞活力显著升高;Mod组较Con组ROS水平增加,ST2825处理后ROS有所下降;与Con组相比,Mod组细胞凋亡率增加,ST2825处理后凋亡率较Mod降低,且呈剂量依赖性。与Con组相比,Mod组CD86表达显著增加,CD163表达降低,提示Mod组细胞向M1型细胞极化;与Mod组相比,两种剂量ST2825处理后CD86表达降低,CD163表达增加,提示ST2825促进缺氧复氧的BV2细胞向M2型细胞极化。qPCR显示,与Con组相比,Mod组细胞TNF-α表达增加,IL-10表达降低,ST2825L组和ST2825H组TNF-α表达相较于Mod组降低,IL-10升高。Western blotting显示,与Con相比,Mod组ARG1、Caspase-1和cleaced Caspase-1表达显著降低,NLRP3、iNOS、IL-1及IL-18表达增加,ST2825低剂量和高剂量处理后ARG1、Caspase-1和cleaced Caspase-1水平均显著增加,NLRP3、iNOS、IL-1及IL-18水平均降低。结论ST2825通过调节小胶质细胞极化减轻脑缺血-再灌注损伤,降低氧化应激及炎症反应,这是减轻脑缺血-再灌注损伤的新途径。

神经干细胞源性外泌体对脑缺血再灌注损伤后大鼠氧化应激和细胞凋亡的影响

目的探讨神经干细胞源性外泌体(NSC-Exos)对脑缺血再灌注损伤(MCAO)模型大鼠氧化应激和神经细胞凋亡的影响。方法135只雄性SD大鼠随机分为Sham组(手术、不缺血、不微量注射)、MCAO组(手术、缺血、不微量注射)及NSC-Exos组(手术、缺血、侧脑室微量注射),于微量注射后大鼠脑缺血再灌注第1、7及14天时行神经功能缺陷评分,2,3,5-三苯基氯化四氮唑(TTC)检测脑组织相对梗死体积,HE染色和透射电子显微镜观察海马CA3区神经细胞形态及亚显微结构,比色法检测海马组织匀浆中谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)和丙二醛(MDA)的含量,Western blot检测海马组织中Bcl-2、Bax蛋白的表达。结果与Sham组相比,MCAO组大鼠神经功能缺陷评分增高(P<0.05),脑组织相对梗死体积显著增大(P<0.05),神经细胞形态及超微结构受损严重,海马组织匀浆中GSH-PX、SOD酶活性降低,MAD含量增高(P<0.05),Bcl-2含量降低、Bax蛋白含量增加(P<0.05);与MCAO组相比,NSC-Exos组大鼠神经功能缺陷评分降低(P<0.05),脑组织相对梗死体积减小(P<0.05),存活神经细胞形态较为完好,超微结构较为清晰,海马组织匀浆中GSH-PX、SOD酶活性均增高,MAD含量减小(P<0.05),Bcl-2蛋白随缺血再灌注时间的延长表达增高,蛋白Bax表达减少(P<0.05)。结论NSC-Exos可改善MCAO大鼠的神经功能,减轻神经元的病理损伤,其机理可能与抑制海马组织的氧化应激和细胞凋亡有关。

Cadmium Activates Reactive Oxygen Species-dependent AKT/mT OR and Mitochondrial Apoptotic Pathways in Neuronal Cells

Objective To examine the role of Cd-induced reactive oxygen species（ROS） generation in the apoptosis of neuronal cells. Methods Neuronal cells（primary rat cerebral cortical neurons and PC12 cells） were incubated with or without Cd post-pretreatment with rapamycin（Rap） or N-acetyl-L-cysteine（NAC）. Cell viability was determined by MTT assay, apoptosis was examined using flow cytometry and fluorescence microscopy, and the activation of phosphoinositide 3’-kinase/protein kinase B（Akt）/mammalian target of rapamycin（m TOR） and mitochondrial apoptotic pathways were measured by western blotting or immunofluorescence assays. Results Cd-induced activation of Akt/m TOR signaling, including Akt, m TOR, p70 S6 kinase（p70 S6K）, and eukaryotic initiation factor 4E binding protein 1（4E-BP1）. Rap, an m TOR inhibitor and NAC, a ROS scavenger, blocked Cd-induced activation of Akt/m TOR signaling and apoptosis of neuronal cells. Furthermore, NAC blocked the decrease of B-cell lymphoma 2/Bcl-2 associated X protein（Bcl-2/Bax） ratio, release of cytochrome c, cleavage of caspase-3 and poly（ADP-ribose） polymerase（PARP）, and nuclear translocation of apoptosis-inducing factor（AIF） and endonuclease G（Endo G）. Conclusion Cd-induced ROS generation activates Akt/m TOR and mitochondrial pathways, leading to apoptosis of neuronal cells. Our findings suggest that m TOR inhibitors or antioxidants have potential for preventing Cd-induced neurodegenerative diseases.