Dexmedetomidine protects cardiomyocytes against hypoxia/reoxygenation injury via multiple mechanisms

BackgroundMyocardial infarction (MI) is a serious cardiovascular disease associated with myocardial ischemia/reperfusion (I/R) injury. Dexmedetomidine (Dex), an α2‐adrenoceptor agonist, has been reported to protect against I/R injury. We examined the cardioprotective effects of Dex on cardiomyocytes under hypoxia/reoxygenation (H/R) conditions and explored the underlying mechanisms.Materials and methodsA H/R model was established to mimic the MI injury. The CCK‐8 assay was performed to measure cell viability. Cellular apoptosis was measured using the Annexin V fluorescein isothiocyanate (FITC)‐propidium iodide (PI) staining. The levels of interleukin (IL)‐1α and tumor necrosis factor (TNF)‐α, and the activity of lactate dehydrogenase (LDH) were measured using a commercial enzyme‐linked immunosorbent assay (ELISA) kit. Reactive oxygen species (ROS) were measured using the 2''‐7’ dichlorofluorescein diacetate (DCFH‐DA) staining assay. In addition, the levels of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD), catalase (CAT), and caspase‐3 were measured using a commercial kit. siRNA was used to silence Bcl‐2, catalase, or STAT3. Western blotting was used to measure the change in the levels of proteins.ResultsDex improved the cell viability and inhibited the inflammatory response in H9c2 cells exposed to H/R treatment. In addition, Dex inhibited apoptosis and alleviated the endoplasmic reticulum (ER) stress and oxidative stress in H9c2 cells under the H/R treatment. Mechanism investigation showed that Dex inhibited the intrinsic pathway of apoptosis. Moreover, Dex enhanced the activation of the JAK2/STAT3 signaling pathway in H/R‐treated H9c2 cells.ConclusionAltogether, our findings suggested Dex as a promising therapeutic agent for myocardial I/R.     

Scoparone protects neuronal cells from oxygen glucose deprivation/reoxygenation injury

Ischemic stroke is one of the leading causes of death and disability in the world. The cerebral ischemia/reperfusion (I/R) injury is considered as the major molecular mechanism in the pathogenesis of ischemic stroke. Scoparone, a major constituent of Artemisia capillaries, has been found to exhibit protective effects against I/R-induced myocardial injury. However, the role of scoparone in cerebral I/R injury has not been elucidated. In the current study, the hippocampal neurons were subjected to oxygen-glucose deprivation/reperfusion (OGD/R) to simulate I/R injury in vitro. The results showed that scoparone improved OGD/R-induced inhibitory effect on cell viability of hippocampal neurons. Scoparone displayed anti-oxidative activity as proved by the decreased levels of reactive oxygen species (ROS) and malondialdehyde (MDA), and increased activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) in OGD/R-induced hippocampal neurons. In addition, cell apoptosis was markedly decreased after scoparone treatment in OGD/R-induced hippocampal neurons. The expression of bax was significantly decreased, while bcl-2 expression was increased in the scoparone pretreated hippocampal neurons. Furthermore, the expressions of nuclear factor E2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) were obviously induced by scoparone. Knockdown of Nrf2 by siRNA transfection dramatically attenuated the protective effects of scoparone on OGD/R-induced hippocampal neurons. Collectively, scoparone protected hippocampal neurons from OGD/R-induced injury via activating Nrf2/HO-1 signaling pathway, suggesting that scoparone might be a potential agent for the ischemic stroke therapy.

Ischemic stroke is one of the leading causes of death and disability in the world.     

Andrographolide up-regulates cellular-reduced glutathione level and protects cardiomyocytes against hypoxia/reoxygenation injury

Recent studies revealed that the herb Andrographis paniculata possesses cardioprotective activities. Using neonatal rat cardiomyocytes, the cardioprotective actions of several diterpene lactones derived from A. paniculata including andrographolide, 14-deoxyandrographolide, 14-deoxy-11,12-didehydroandrographolide, and sodium 14-deoxyandrographolide-12-sulfonate were investigated. Pretreatment with andrographolide but not with the other compounds protected the cardiomyocytes against hypoxia/ reoxygenation injury and up-regulated the cellular-reduced glutathione (GSH) level and antioxidant enzyme activities. The cardioprotective action of andrographolide was found to coincide in a time-dependent manner with the up-regulation of GSH, indicating the important role of GSH. The cardioprotective action of andrographolide was also completely abolished by buthionine sulfoximine, which acts as a specific gamma-glutamate cysteine ligase (GCL) inhibitor to deplete cellular GSH level. It was subsequently found that the mRNA and protein levels of the GCL catalytic subunit (GCLC) and modifier subunit (GCLM) were up-regulated by andrographolide. Luciferase reporter assay also demonstrated that andrographolide activated both the GCLC and the GCLM promoters in the transfected rat H9C2 cardiomyocyte cell line. The 12-O-tetradecanoylphorbo-13-acetate response element or the antioxidant response element may be involved in the transactivating actions of andrographolide on the GCLC and GCLM promoters. The present study pinpoints andrographolide as a cardioprotective principle in A. paniculata and reveals its cytoprotective mechanism.     

腺病毒介导的热休克蛋白70在神经元和胶质细胞中的抗缺氧研究

目的 探讨重组腺病毒介导的热休克蛋白70(HSP70)表达对神经元和胶质细胞缺氧/再复氧损伤的保护作用.方法 制备携带全长HSP70基因的重组腺病毒vAd-HSP70.感染体外培养的神经元和胶质细胞,检测靶细胞中外源性HSP70的表达.感染vAd-HSP70 24、48、72 h组和感染vAd-GFP对照组的细胞经缺氧/再复氧处理后,分别测定细胞活性、细胞培养上清液中乳酸脱氢酶(LDH)活性及线粒体和胞质内细胞色素C含量.结果 感染vAd-HSP70的神经细胞可检测到外源性HSP70基因表达.经缺氧/再复氧处理,感染vAd-HSP70组细胞活性较感染vAd-GFP对照组明显增强(P均＜0.05);感染vAd-HSP70 24、48、72 h组细胞培养上清液中LDH活性[(1 480±121)、(1 023士106)、(1 132±197)U/L]均明显低于感染vAd-GFP对照组[(1 976±190)U/L],线粒体中细胞色素C含量(0.986±0.012、1.028±0.007、1.014±0.008)均明显高于感染vAd-GFP对照组(0.970±0.003),而胞质中的细胞色素C含量(0.987±0.008、0.960±0.005、0.964±0.003)则低于感染vAd-GFP对照组(1.011±0.005,P＜0.05或P＜0.01),其中以感染48 h最为理想(P均＜0.01).结论 腺病毒介导的外源性HSP70表达可保护神经元和胶质细胞抵抗缺氧/再复氧损伤,具有明确的细胞保护作用.     

油茶皂苷C对脐静脉内皮细胞缺氧及复氧损伤时的影响

目的:研究脐静脉内皮细胞(HUVEC)缺氧/复氧损伤(A/R)时,单核细胞与内皮细胞黏附及细胞间黏附分子-1(ICAM-1)mRNA表达并观察油茶皂苷C(SQS-C)对此的影响。方法:内皮细胞A/R前3h,分别加入终浓度为0.1,1.0和10.0μmol/LSQS-C,再A/R5h,比色法测定内皮细胞与单核细胞的黏附率,RT-PCR法检测内皮细胞ICAM-1mRNA的表达。结果:A/R时,单核细胞与内皮细胞的黏附显著增加(P<0.01);SQS-C能明显降低细胞黏附率,减少内皮细胞ICAM-1mRNA的表达(P<0.05),并呈剂量依赖性。结论:SQS-C能抑制缺氧/复氧损伤的内皮细胞与单核细胞的黏附,减少内皮细胞ICAM-1mRNA的表达。     

人近曲肾小管上皮细胞缺氧/复氧损伤模型的建立

目的 建立一种新的人近曲肾小管上皮细胞HK-2缺氧／复氧损伤模型。方法 本实验使用人近曲HK-2。实验分为缺氧4、12和24h及缺氧24h后复氧4、12和24h组，每个实验组均设立空白对照组。采用经高温灭菌的液体石蜡覆盖法造成缺氧环境；苔盼兰摄取法进行细胞计数及检测细胞存活率，生化法检测培养基中的乳酸脱氢酶（LDH）含量。结果 人肾小管上皮细胞经过缺氧／复氧处理后，苔盼兰摄取率显著提高，细胞存活率显著下降，LDH含量升高。说明缺血-再灌注损伤导致了细胞膜的完整性破坏，甚至细胞发生了不可逆转的损伤。结论 采用液体石蜡覆盖法建立人近曲肾小管上皮细胞缺氧／复氧损伤模型，较其他制模方法操作简单、易行、可靠。     

缺氧/复氧损伤人脐静脉内皮细胞黏附分子表达与新型植物雌激素α-玉米赤霉醇的影响

目的:探讨新型植物雌激素α-玉米赤霉醇对缺氧/复氧损伤后人脐静脉内皮细胞黏附分子表达的干预,并与内源性动物雌激素雌二醇的作用进行比较。方法:实验于2005-10/2006-01在首都医科大学完成。①健康产妇的婴儿脐带由首都医科大学附属宣武医院妇产科提供,产妇及其家属签署捐赠同意书。α-玉米赤霉醇(中国农业大学提纯,纯度99%以上,以乙醇作为溶剂),雌二醇(Sigma公司)。②脐静脉内皮细胞原代培养后,用质量浓度为1.25g/L的胰蛋白酶 0.1g/L的乙二胺四乙酸混合消化液进行传代,传至2～3代后用于实验。细胞以3×105/孔接种于24孔培养板,待生长至80%～90%融合后,设立10组:正常对照组、模型对照组、α-玉米赤霉醇1,10,100,1000nmol/L组、雌二醇1,10,100,1000nmol/L组,6孔/组。③除正常对照组外,其余各组细胞均复制缺氧/复氧损伤模型,置于体积分数为0.93的N2 0.05的CO2 0.02的O2缺氧环境中3h,然后恢复正常氧供应1h。α-玉米赤霉醇各组于造模前20min分别加入α-玉米赤霉醇,使细胞培养液中α-玉米赤霉醇终浓度分别达到1,10,100,1000nmol/L;雌二醇各组于造模前20min分别加入雌二醇,使细胞培养液中雌二醇终浓度分别达到1,10,100,1000nmol/L;正常对照组、模型对照组不予任何药物处理。④吸取各组上清液,按酶联免疫吸附试剂盒说明操作分别测定各孔可溶性E-选择素、细胞间黏附分子1、血管细胞黏附分子1的含量。结果:①缺氧/复氧后各组细胞E-选择素含量的比较:与正常对照组比较,缺氧3h/复氧1h后模型对照组脐静脉内皮细胞上清液中的E-选择素含量明显升高[(1.77±0.36),(5.62±0.74)pg/L,P<0.01]。与模型对照组比较,α-玉米赤霉醇1,10,100,1000nmol/L组E-选择素含量均明显降低[(5.62±0.74),(3.53±1.21),(3.16±0.94),(2.79±1.78),(2.18±0.75)pg/L,P<0.05或0.01],雌二醇1,10,100,1000nmol/L组E-选择素含量亦均明显降低[(5.62±0.74),(3.72±0.42),(2.99±0.61),(2.45±0.99),(2.34±0.70)pg/L,P<0.01],且呈剂量依赖性。相同质量浓度的α-玉米赤霉醇与雌二醇作用差异无显著性意义(P>0.05)。②缺氧/复氧后各组细胞间黏附分子1、血管细胞黏附分子1含量的比较:与E-选择素含量情况相似。结论:①人脐静脉内皮细胞给予α-玉米赤霉醇预处理后,可显著抑制由缺氧/复氧损伤所引起的黏附分子高表达,且呈剂量依赖性,保护内皮细胞免受炎症递质损伤。②与相同浓度的雌二醇抑制作用相似,是一种有一定应用前景的雌激素替代药物。     

Protective role of retinoid X receptor in H9c2 cardiomyocytes from hypoxia/reoxygenation injury in rats

BACKGROUND:

Retinoid X receptor (RXR) plays a central role in the regulation of intracellular receptor signaling pathways. The activation of RXR has protective effect on H₂O₂-induced apoptosis of H9c2 ventricular cells in rats. But the protective effect and mechanism of activating RXR in cardiomyocytes against hypoxia/reoxygenation (H/R)-induced oxidative iniury are still unclear.

METHODS:

The model of H/R injury was established through hypoxia for 2 hours and reoxygenation for 4 hours in H9c2 cardiomyocytes of rats. 9-cis-retinoic acid (9-cis RA) was obtained as an RXR agonist, and HX531 as an RXR antagonist. Cultured cardiomyocytes were randomly divided into four groups: sham group, H/R group, H/R+9-cis RA -pretreated group (100 nmol/L 9-cis RA), and H/R+9-cis RA+HX531-pretreated group (2.5 μmol/L HX531). The cell viability was measured by MTT, apoptosis rate of cardiomyocytes by flow cytometry analysis, and mitochondrial membrane potential (ΔΨm) by JC-1 fluorescent probe, and protein expressions of Bcl-2, Bax and cleaved caspase-9 with Western blotting. All measurement data were expressed as mean±standard deviation, and analyzed using one-way ANOVA and the Dunnett test. Differences were considered significant when P was <0.05.

RESULTS:

Pretreatment with RXR agonist enhanced cell viability, reduced apoptosis ratio, and stabled ΔΨm. Dot blotting experiments showed that under H/R stress conditions, Bcl-2 protein level decreased, while Bax and cleaved caspase-9 were increased. 9-cis RA administration before H/R stress prevented these effects, but the protective effects of activating RXR on cardiomyocytes against H/R induced oxidative injury were abolished when pretreated with RXR pan-antagonist HX531.

CONCLUSION:

The activation of RXR has protective effects against H/R injury in H9c2 cardiomyocytes of rats through attenuating signaling pathway of mitochondria apoptosis.KEY WORDS: Retinoid X receptor, Cardiomyocytes, Apoptosis, Mitochondria, Hypoxia reoxygenation     

氢气预处理对乳鼠心肌细胞缺氧/复氧损伤的影响

目的:探讨氢气对乳鼠心肌细胞缺氧/复氧损伤的影响及其机制。方法:原代培养的SD乳鼠心肌细胞,随机分3组即对照组、缺氧/复氧组、氢气预处理组。对照组常规培养;缺氧/复氧组预先在100%N2环境中培养60min,复氧30min;氢气预处理组预先在2%H2+98%N2环境中培养60min,复氧30min。采用TUNEL法、MDA试剂盒法和MTT法分别检测乳鼠心肌细胞细胞凋亡率、丙二醛(MDA)含量和细胞活力。结果:氢气预处理能够降低乳鼠心肌细胞的凋亡率(P<0.05),减少MDA的生成(P<0.05),增强细胞活力(P<0.05)。结论:氢气预处理对心肌细胞缺氧/复氧损伤具有保护作用,可能机制是抗脂质过氧化抑制细胞凋亡提高细胞活力。     

氟伐他汀对缺氧复氧处理的猪颈总动脉内皮细胞氧化还原功能及ICAM-1表达的影响

目的探讨3-羟-3-甲基戊二酸单酰辅酶A(HMG-CoA)还原酶抑制剂在缺血再灌注过程中的内皮保护作用。方法培养猪颈动脉血管内皮细胞(PCAEC),以0.1μmol/L、0.2μmol/L、0.5μmol/L、1.0μmol/L的氟伐他汀(来适可)共生长44 h,经缺氧1 h复氧3 h处理,以血清免疫学及细胞免疫化学方法测定MTT、GSH-PX、MDA、SOD、ICAM-1的值,观察氟伐他汀对缺氧复氧(H/RI)处理的猪颈总动脉内皮细胞氧化还原功能及细胞间黏附因子-1(ICAM-1)表达的影响。结果0.5μmol/L氟伐他汀干预的H/RI后细胞活力与单纯H/RI组有明显差别(P=0.01);H/RI可明显降低培养细胞的SOD活性,产生MDA较氟伐他汀组及正常对照组间有明显升高(P=0.001),正常对照组及氟伐他汀组与H/RI组间GSH-PX对照有明显差别(P=0.002);ICAM-1细胞免疫化学染色各组间均有显著差别(P=0.018)。结论适当浓度的氟伐他汀对缺氧复氧的内皮细胞功能具有保护作用。     

Uqcrc1的 RNA 干扰片段筛选及其对 H9C2心肌细胞耐受缺氧/复氧损伤的影响

目的：筛选泛醇-细胞色素c还原酶核心蛋白（Ubiquinol-cytochrome c reductase core protein 1, Uqcrc1）高效的 RNA 干扰片段,探讨 Uqcrc1基因沉默对大鼠 H9C2心肌细胞耐受缺氧/复氧（hypoxia/reoxygenation,H/R）损伤的影响。方法制备三种针对Uqcrc1的RNA干扰片段,采用RT-PCR和Western blot检测Uqcrc1 RNA干扰片段转染后Uqcrc1基因和蛋白的表达,从中筛选出最有效的RNA干扰片段及转染浓度,采用MTT法和LDH试剂盒分别检测H/R损伤后H9C2心肌细胞的存活率和LDH漏出率。结果靶序列为CCGUUGCUGUAGCUAACAAdTdT的siUqcrc1片段对Uqcrc1 mRNA的抑制作用最明显,在转染浓度为200 nmol/L时对Uqcrc1蛋白表达抑制最明显。靶向Uqcrc1的RNA干扰片段转染降低了H9C2心肌细胞耐受H/R损伤的能力。与阴性对照组相比,Uqcrc1基因沉默组H9C2心肌细胞H/R损伤后的存活率显著降低,LDH漏出率升高（P＜0.01）。结论 Uqcrc1在心肌细胞耐受H/R损伤中起了重要作用,它可能是心肌保护的又一个关键靶点。     

地高辛抗血清对老龄大鼠心肌缺氧复氧损伤影响的体外实验

目的:观察内洋地黄素水平在老龄大鼠心肌细胞缺氧复氧损伤中的变化以及地高辛抗血清的保护作用。方法:实验于2005-04/05在皖南医学院病理生理教研室完成。取10只24月龄和10只6月龄雄性普通级SD大鼠,分别制备青年和老龄大鼠心肌细胞匀浆,老龄和成年大鼠为两大组,每组分为7小组,即每只大鼠心肌随机分到各小组中,共计14小组,每组10支试管。正常对照组:给予CO2和O2的混合气体(1∶19)通气40min;缺氧复氧组:CO2,O2,N2混合气体(5∶4∶91)通气20min后换成CO2和O2的混合气体(1∶19)通气20min;阴性对照组:同缺氧复氧组,但于再给氧前加入0.1mL的非特异性灭活兔血清;地高辛抗血清组:同缺氧复氧组,但于再给氧前加入0.1mL的非特异性地高辛抗血清(分别为1∶90000,60000,30000,10000)。观察大鼠心肌细胞钠-钾-三磷酸腺苷酶活性和线粒体内钙聚集程度,分析其剂量-效应关系。结果:①缺氧复氧时,青年组和老龄组大鼠心肌分泌内洋地黄素均显著升高,但老龄组显著低于青年组[(0.081±0.03),(0.153±0.06);(0.074±0.04),(0.125±0.05)ng/g;P<0.05]。②缺氧复氧时,老龄组与青年组心肌细胞钠-钾-三磷酸腺苷酶活性显著受抑制[(0.239±0.015),(0.778±0.050);(0.350±0.047),(0.836±0.044)μkat/g;P<0.05],老龄组与青年组相比,其抑制效应显著增强(P<0.05)。③缺氧复氧时,老龄组线粒体内钙与青年组比较明显增强[(0.082±0.011),(0.495±0.095);(0.075±0.008),(0.412±0.084)mmol/L,P<0.05]。④老龄组和青年组相比,地高辛抗血清呈剂量依赖性的恢复钠-钾-三磷酸腺苷酶活性(r=0.695,0.797,n=5,P<0.05),减轻线粒体内钙聚集(r=-0.565,-0.649,n=5,P<0.05);经直线回归分析发现,老龄鼠回归系数大于青年组(酶活性抑制K=1.50,0.94,线粒体内钙K=-7.43,-6.46)。结论:心肌细胞缺氧复氧时,老龄鼠损伤较青年大鼠更显著,其机制与老龄大鼠心肌细胞钠-钾-三磷酸腺苷酶对内洋地黄素敏感性增加有关,地高辛抗血清对老龄大鼠心肌细胞缺氧复氧保护作用更有效。     

促红细胞生成素对心肌细胞缺氧/复氧损伤的保护作用

目的探讨促红细胞生成素（EP0）对心肌细胞缺氧／复氧（HR）损伤的保护作用及其机制。方法对乳鼠心肌细胞进行原代分离培养,并缺氧2h,复氧1h,建立HR损伤模型。心肌细胞随机分为四组：正常细胞培养组（空白组）,HR组,HR＋EPO 10U／ml组（EPO组）,HR＋EPO10U／ml＋U0126 10μmol／L组（U0126组）。全自动生化分析仪检测各组细胞培养液LDH活性;MTT法检测心肌细胞活性;TUNEL法：流式细胞仪Annexin—V—FITC法检测凋亡心肌细胞;Westem—blot法测定各组心肌细胞ERK1/2和磷酸化ERK1/2蛋白含量。结果EPO显著降低心肌细胞HR损伤后LDH的漏出,增强细胞的活性,减少细胞的凋亡比例,提高ERK。蛋白磷酸化水平;而经过U0126（MAPK的阻滞剂）的处理,心肌细胞LDH外溢量增加,细胞活性显著下降,凋亡细胞的比例明显增加,且ERK1/2蛋白磷酸化水平显著降低。结论EPO对心肌细胞HR损伤有一定的保护作用,其机制与ERK1/2信号通路的激活及抑制心肌细胞凋亡有关。     

Exogenous NAD+ supplementation protects H9c2 cardiac myoblasts against hypoxia/reoxygenation injury via Sirt1‐p53 pathway

Nicotinamide adenine dinucleotide (NAD⁺) not only transfers electrons in mitochondrial respiration, but also acts as an indispensable cosubstrate for Sirt1, the class III histone/nonhistone deacetylase. However, NAD⁺ is depleted in myocardial ischemia/reperfusion (IR) injury. The objective of this study was to investigate the role of exogenous NAD⁺ supplementation in hypoxia/reoxygenation (HR)‐stressed H9c2 cardiac myoblasts. Firstly, the effects of distinct treating time points and doses of NAD⁺ supplementation on the viability of HR‐stressed H9c2 cells were detected. Secondly, intracellular NAD⁺ levels in HR‐stressed H9c2 cells at various extracellular NAD⁺ concentrations were determined. Thirdly, the role of NAD⁺ supplementation in HR‐induced cell apoptosis and its relevance to Sirtuin 1‐p53 pathway were investigated. Exogenous NAD⁺ supplementation elevated intracellular NAD⁺ level and reduced HR‐induced cell death in both time‐ and concentration‐dependent manners. It appeared that NAD⁺ supplementation exerted the greatest protection when extracellular concentration ranged from 500 to 1000 μm and when NAD⁺ was added immediately after reoxygenation began. NAD⁺ replenishment restored Sirt1 activity, reduced the acetylation level of p53 (Lys373 & 382), and attenuated cell apoptosis in HR‐stressed H9c2 cells, whereas inhibition of Sirt1 activity alleviated the effects of NAD⁺ replenishment. These results indicated that exogenous NAD⁺ supplementation attenuated HR‐induced cell apoptosis, which was at least partly mediated by restoring Sirt1 activity and subsequently inhibiting p53 activity via deacetylating p53 at lysine 373 and 382.     

Retracted Article: Long noncoding RNA ANRIL protects cardiomyocytes against hypoxia/reoxygenation injury by sponging miR-195-5p and upregulating Bcl-2

Long noncoding RNAs have been widely accepted to play important roles in acute myocardial infarction (AMI). The dysregulation of cyclin-dependent kinase inhibitor 2B antisense RNA 1 (ANRIL) was discovered in AMI patients. Nevertheless, the detailed role and molecular mechanisms of ANRIL in AMI remain indistinct. The levels of ANRIL, miR-195-5p and Bcl-2 mRNA were determined by qRT-PCR. western blot was performed to assess the expression of Bcl-2, Bax, Cyclin D1 and p21. Cell proliferation was detected by CCK-8 assay, and cell apoptosis was measured by flow cytometry. The targeted correlation between ANRIL and miR-195-5p was confirmed by the dual-luciferase reporter and RNA pull-down assays. Our data revealed that ANRIL was downregulated and miR-195-5p was upregulated in the serum of AMI patients and hypoxia/reoxygenation (H/R)-induced myocardial cells. ANRIL upregulation or miR-195-5p knockdown alleviated H/R-induced myocardial cell injury. Moreover, ANRIL sequestered miR-195-5p by acting as a sponge of miR-195-5p. ANRIL upregulated Bcl-2 expression by sponging miR-195-5p. Additionally, ANRIL overexpression alleviated H/R-induced myocardial cell injury by upregulating Bcl-2. In conclusion, our study indicated that ANRIL upregulation alleviated H/R-induced myocardial cell injury partially through sponging miR-195-5p and upregulating Bcl-2, highlighting its role as a promising mediator for new therapies for AMI treatment.

Long noncoding RNAs have been widely accepted to play important roles in acute myocardial infarction (AMI).     

高压氧对缺氧/复氧模型下大鼠骨髓间充质干细胞的影响及其相关机制

目的:探讨高压氧对缺氧/复氧模型下大鼠骨髓间充质干细胞的影响及其相关机制。方法:选取3—4周龄SD雄性大鼠,采用全骨髓贴壁法培养至P3代,随机分为正常组A(细胞置于常规培养箱内培养)、缺氧/复氧组B(置于95%N2、5%CO_2密闭培养箱中培养9h,复氧6h)、缺氧/复氧+高压氧组C(90%O_2,2.5ATA、90min)、缺氧/复氧+高压氧+YC-1组D,实验组其余时间处理和正常组相同。A、B、C、D组均于处理结束12h后行CCK-8比色法、流式细胞仪检测细胞存活率及凋亡率。Western blot检测HIF-1α、β-catenin、LEF-1蛋白表达水平。结果:(1)与A组相比,缺氧/复氧后B、C、D组细胞存活率明显降低,差异具有显著性意义(P0.05),给予高压氧后C组存活率比B组升高,D组存活率较C组降低(P0.05)。(2)实验组B、C相比,C组中HIF-1α、β-catenin、LEF-1蛋白表达水平升高(P0.05)。(3)实验组C、D组相比,给予YC-1阻断剂后HIF-1α、β-catenin、LEF-1蛋白表达减少(P0.05)。结论:高压氧能够提高缺氧环境下骨髓间充质干细胞存活率,其机制可能与调控HIF-1α介导的Wnt通路有关。     

缺氧预适应对缺氧复氧诱导内皮细胞-中性粒细胞黏附的影响

目的：观察缺氧预适应对缺氧／复氧后血管内皮细胞表面黏附分子的表达以及中性粒细胞－内皮细胞黏附的影响。方法：采用β－N－乙酰氨基己糖苷酶比色法检测黏附率;流式细胞术检测内皮细胞表面黏附分子E－选择素、细胞间黏附分子－1（ICAM－1）的表达;苔盼蓝摄取法检测细胞存活率;常规生化法检测乳酸脱氢酶活性。结果：血管内皮细胞经缺氧／复氧处理后,苔盼蓝摄取率,乳酸脱氢酶活性均明显增高,E－选择素、ICAM－1表达明显上调,其表面中性粒细胞的黏附增加,缺氧预适应显著抑制缺氧／复氧的上述作用。结论：缺氧预适应通过调节内皮细胞表面黏附分子的表达,抑制缺氧／复氧诱导的内皮细胞－中性粒细胞黏附。     

黄芩素通过抗氧化及调节细胞内钙离子浓度抑制大鼠缺氧/复氧诱导的心肌细胞凋亡

背景:黄芩素对缺氧复氧损伤的心血管有保护作,但机制至今不清。目的:探讨中药黄芩素对心肌细胞缺氧/复氧损伤导致心肌细胞凋亡的保护作用机制。方法:体外培养大鼠乳鼠心肌细胞培养。实验分3组:正常对照组为正常培养的心肌细胞未做处理;缺氧/复氧组为应用缺氧/复氧方法诱导心肌细胞凋亡损伤;黄芩素预处理组为经黄芩素预处理30min后经缺氧/复氧诱导的心肌细胞。通过检测培养基上清液中乳酸脱氢酶活力检测细胞损伤程度及黄芩苷保护作用;应用原位末端标记细胞法标记细胞后,流式细胞检测心肌细胞凋亡率;应用免疫印迹方法检测心肌细胞凋亡蛋白Bax与抗凋亡蛋白Bcl-2的蛋白表达水平;应用Fura-2-AM负载心肌细胞,实时检测心肌细胞内Ca2+浓度变化。结果与结论:与正常对照组相比,缺氧/复氧组上清液乳酸脱氢酶活性、心肌细胞凋亡率、Bax蛋白含量、心肌细胞Ca2+浓度均增加(P<0.05),Bcl-2蛋白含量降低(P<0.05)。与缺氧/复氧组相比,黄芩素预处理组乳酸脱氢酶含量、心肌细胞凋亡率、Bax蛋白含量及心肌细胞Ca2+浓度均降低(P<0.05),Bcl-2蛋白含量增加(P<0.05)。证实黄芩素能抑制缺氧/复氧导致的心肌细胞凋亡,其作用机制可能与抗氧化与调节心肌细胞内钙离子浓度有关     

环磷酸腺苷和一氧化氮在后适应保护缺氧/复氧损伤心肌细胞中的作用

背景:周期性的环磷酸腺苷浓度改变参与了预适应对缺血心脏的保护作用.目的:观察环磷酸腺苷和一氧化氮在缺氧/复氧心肌细胞后适应保护机制中的可能作用.方法:原代培养SD乳鼠心肌细胞,随机分为11组分别处理:正常对照组、缺氧/复氧组、心肌缺血后适应组、心肌缺血后适应+咯利普兰组、心肌缺血后适应+SQ22536或左旋精氨酸+心肌缺血后适应组,咯利普兰、SQ22536或各浓度Nω-硝基精氨酸+缺氧/复氧组.结果与结论:心肌缺血后适应能显著改善缺氧/复氧损伤造成的心肌细胞活力下降,减少乳酸脱氢酶、肌酸激酶的释放,降低一氧化氮、肿瘤坏死因子α和白细胞介素β的mRNA表达;咯利普兰能进一步增强后适应对心肌细胞的保护作用,而腺苷酸环化酶抑制剂SQ22536可显著减弱该作用;20,100 μmol/L 非选择性一氧化氮合酶抑制剂Nω-硝基-左旋精氨酸能发挥类似于后适应的保护作用,而在1 000 μmol/L时则损伤心肌细胞(P < 0.05).证实心肌缺血后适应对缺氧/复氧损伤心肌细胞的保护,可能是通过增强环磷酸腺苷信号抑制炎症过程实现的.     

环磷酸腺苷和一氧化氮在后适应保护缺氧/复氧损伤心肌细胞中的作用

背景：周期性的环磷酸腺苷浓度改变参与了预适应对缺血心脏的保护作用。目的：观察环磷酸腺苷和一氧化氮在缺氧/复氧心肌细胞后适应保护机制中的可能作用。方法：原代培养SD乳鼠心肌细胞,随机分为11组分别处理：正常对照组、缺氧/复氧组、心肌缺血后适应组、心肌缺血后适应＋咯利普兰组、心肌缺血后适应＋SQ22536或左旋精氨酸＋心肌缺血后适应组,咯利普兰、SQ22536或各浓度Nω-硝基精氨酸＋缺氧/复氧组。结果与结论：心肌缺血后适应能显著改善缺氧/复氧损伤造成的心肌细胞活力下降,减少乳酸脱氢酶、肌酸激酶的释放,降低一氧化氮、肿瘤坏死因子α和白细胞介素β的mRNA表达;咯利普兰能进一步增强后适应对心肌细胞的保护作用,而腺苷酸环化酶抑制剂SQ22536可显著减弱该作用;20,100μmol/L非选择性一氧化氮合酶抑制剂Nω-硝基-左旋精氨酸能发挥类似于后适应的保护作用,而在1000μmol/L时则损伤心肌细胞（P〈0.05）。证实心肌缺血后适应对缺氧/复氧损伤心肌细胞的保护,可能是通过增强环磷酸腺苷信号抑制炎症过程实现的。